RTI PMX-III X-Ray User manual

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PMX-III

X-ray multimeter version 6.0

oRTIgo version 3.0

Declaration of conformity

We, RTI Electronics AB, Göteborgsvägen 97 / 50, SE-431 37 MÖLNDAL, Sweden,

declare under our sole responsibility that the product:

Product name:

Type of equipment:

PMX-III

X-ray multimeter; kVp, exposure time, and dose meter

Intended use of this product:

Accessory to diagnostic X-ray equipment, to be used

Model name:

R/M, R/CT, PH

for service and quality control.

is in conformity with the following standards:

Medical electrical equipment Part 1: General requirements for safety (COUNCIL DIRECTIVE 93/42/EEC, Annexes V and VII) Part 2: Collateral standard: Electromagnetic compatibility - Requirements and tests (EN 60601-1-2: 1993)

following the provisions of the 93/42/EEC Medical Devices Directive.

Mölndal, 1998-11-13, ……………………………………

Lars Herrnsdorf, Vice President

Address: RTI Electronics AB  Göteborgsvägen 97 / 50  SE-431 37 MÖLNDAL  Sweden Phone: +46 (0)31 746 36 00  Fax: +46 (0)31 27 05 73  E-mail: info@rti-e.se  Web: www.rti-e.se

2-CE-03000-2 Tillverkardeklaration PMX-III.DOC

NOTICE

RTI Electronics AB reserves all rights to make changes in the PMX-III family of meters and the information in this document without notice. RTI Electronics AB assumes no responsibility for any errors or consequential damages that may result from the use or misinterpretation of any information contained in this document.

NOTE! This user manual is valid for PMX-III with the following version: 6.0

IBM is a registered trademark of International Business Machines Corporation. HP is a registered trademark of Hewlett-Packard Company. Appletalk and Macintosh are registered trademarks of Apple Computer, Incorporated. Microsoft, Windows and Windows 95 are registered trademarks of Microsoft Corporation. Pentium is a registered trademark of Intel Corporation

RTI Electronics AB Göteborgsvägen 97 / 50 SE-431 37 MÖLNDAL Sweden Phone: Int +46 31 746 36 00 Fax: Int +46 31 270 573 E-mail: info@rti-e.se Web: http://www.rti-e.se

PMX-III Manual 1999-03/6.0B I-1

PREFACE

Chapter 1 Gives an introduction to the PMX-III.

Description of ADI, applications and typical use

Chapter 2 Describes general functions and connectors

Chapter 3 Set up the system for measurements

Chapter 4 Learn to make basic QC measurements.

Chapter 5 Service and Maintenance related measurements

II,, Dose/frame, DSI, and light measurements.

PREFACE

Chapter 6 Remote control of the PMX-III using oRTIgo.

Chapter 7 Display code list and kVp correction graph.

Chapter 8 Precautions and maintenance.

Chapter 9 Detector range and detector selection guide,

problem report document.

Chapter 10 Hints and troubleshooting, backup of calibration data

Index Important words are listed in alphabetical order.

It is advisable to read through the user manual at least once to gain familiarity with the terms used and the capabilities of the PMX-III. It is possible to make measurements quickly with a minimum of reading. To do this read the instructions on the top panel of the instrument.

Consult the PMX-III reference manual for more specific information.

Note! The PMX-III is intended for service and quality control of diagnostic X-ray equipment. It is not intended for for use during or together with diagnostic examinations of patients.

I-2 1999-03/6.0B PMX-III Manual

I-NOTICE ............................1

I-PREFACE ...........................2

1-INTRODUCTION .......................7

1.1 Overview .........................7

1.2 Package Information and Changes Version 6.0 ....8

1.3 Options and Accessories ................8

1.4 Application Notes ....................8

1.5 About oRTIgo Version 3.0................8

1.6 About ADIs ........................9

1.6.1 What is the Function of an ADI ............9

1.6.2 What to do when Changing an ADI..........9

1.6.3 Any Precautions? ...................9

TOC

1.6.4 How to Choose the Correct ADI Module .......9

1.7 Shortform Detector Selection Guide ..........10

1.8 Typical Use .......................11

2-DESCRIPTION OF PMX-III ..................13

2.1 Front Panel ........................13

2.2 The Display........................13

2.3 The LED Indicators ...................14

2.4 Front Panel Keys ....................16

2.5 Back Panel and AMP-1 .................17

2.6 The Battery Case ....................18

2.7 Top Panel.........................19

2.8 Special Remarks for Use of ADI 8/A(P1) ........20

2.9 AMP-1 Front Panel....................21

2.10 Operation of Principle of the Electrometer .....21

3-HOW TO SET UP THE SYSTEM ..............23

4-BASIC QC MEASUREMENTS ................25

4.1 kVp and Time (Multimeter Mode) ...........25

PMX-III Manual 1999-03/6.0B 3

4.1.1 PARAMETER.....................25

4.1.2 MODE ........................25

4.1.3 When to use SET and LOCK modes .........25

TOC

4.1.4 When and how to use manual LOCK mode .....26

4.1.5 When to use LF and HF: ...............26

4.1.6 TUBE/FILTER ....................27

4.1.7 Measurement with the MAM/RAD version ......28

4.1.8 Default values for F3-F5 (MAM/RAD version) ....29

4.1.9 CT kVp Measurement with the CT/RAD version ...29

4.2 Dose and Dose Rate (Dosimeter Mode)........31

4.2.1 When and How to Use Manual LOCK Mode .....32

4.2.2 How to Use Free Run/Trig Mode ...........32

4.2.3 Active Keys ......................33

4.2.4 How to Make a Measurement ............35

4.3 The Waveform Analyzer ................36

4.3.1 Examples of waveforms ...............37

4.3.2 Waveform flowchart .................38

4.4 Using preamplifier AMP-1 ................39

4.5 Measurements with the AMP-1 ............41

4.5.1 General .......................41

4.5.2 Detector Range and Identification Codes ......42

5-SERVICE / MAINTENANCE .................43

5.1 Introduction .......................43

5.1.1 New Version of Firmware for PMX-III. ........43

5.1.2 Extension Cable Added. ...............44

5.1.3 Probe Holder Added. .................44

5.1.4 ADIs Removed from Detector Cables. ........44

5.1.5 Maintenance. .....................44

5.2 Entrance Dose Rate Measurements ..........45

5.2.1 Very Low Entrance Dose Rate to an Image Intensifier 45

5.2.2 Hints .........................47

5.2.3 Example of Dose Rate Waveforms .........48

5.3 Fluoroscopy low mA ..................48

5.3.1 II-Entrance Dose Rate (µGy/s) ............48

4 1999-03/6.0B PMX-III Manual

5.4 Exposure Dose .....................49

5.4.1 Fluorography and Radiography............49

5.5 Measurement of kVp...................50

5.5.1 Long Exposure time, Skin Dose, and Dose Rate

(SET MODE) ........................50

5.5.2 Short Exposure Time, Skin Dose and Dose Rate

(MANUAL LOCK MODE) ..................51

5.6 Light Measurements, Detector and Adapters .....52

5.6.1 Introduction ......................52

5.6.2 Measurement of Luminance (cd/m²) .........55

5.6.3 Measurements on CRTs and Film Viewing Boxes . . 56

5.6.4 Ambient Light and Other Sources of Error ......57

5.7.3 Measurement of Illuminance (lx) ...........59

5.7 Examples of Field Measurements ...........60

5.7.1 Check the total Contrast Range for the System,

From the Image Intensifier to the Monitor. .........60

5.7.2 Check that the Dose and Dose Rate Level is within

Specification for all II Formats. ...............61

6-REMOTE CONTROL USING ORTIGO ............63

6.1 Introduction .......................63

TOC

6.2 oRTIgo version 3.0....................64

6.3 Connecting PMX-III to a Computer ...........65

6.4 Start oRTIgo 3.0 .....................66

6.5 What is a Record.....................67

6.6 Application example...................68

6.7 List of Hotkeys and Short Cuts .............76

6.7.1 General ........................76

6.7.2 Waveform Analyzer..................78

6.7.3 Text Editor and NotePad ...............79

7-DISPLAY CODES, SENSITIVITY AND FILTRATION ....81

7.1 Display codes ......................81

7.1.1 Most Common Display Codes ............81

7.1.2 Description of the Display Codes ...........82

7.2 KVp Sensitivity Graph ..................85

PMX-III Manual 1999-03/6.0B 5

7.3 Filtration Dependence ..................86

7.4 KVp Correction Graphs .................88

7.4.1 Radiographic - CA-1, 2.0-5.5 mm Al .........88

TOC

7.4.2 Radiographic CA-1, 3.0, 4.0, and

5.0 mm Al+0.1 mm Cu ...................89

8-PRECAUTIONS AND MAINTENANCE............91

8.1 Safety Rules .......................91

8.2 Precautions .......................91

8.3 Maintenance .......................92

9-Notes and Reports .....................93

9.1 Application Notes Related to PMX-III..........93

9.2 Problem report ......................98

10-HINTS AND TROUBLESHOOTING .............99

10.1 Hints...........................99

10.1.1 General Info .....................99

10.1.2 oRTIgo Measurement ................99

10.2.1 Dose Measurements ................101

10.2.2 Questions on kV Measurements ..........104

10.2.3 Light Measurements.................104

10.2.4 General Questions .................105

10.2 Troubleshooting ....................106

10.3 Save EEPROM and ADI data..............108

10.3.1 Backup of internal EEPROM and ADI Modules . . 108

10.4 Restoring data from backup ..............110

10.4.1 Restore the content of PMX-III internal EEPROM . 110

INDEX ..............................113

6 1999-03/6.0B PMX-III Manual

INTRODUCTION Overview

1 INTRODUCTION

1.1 Overview

PMX-III is a combined dosimeter and multimeter with a waveform analyzer for both stand alone and remote control use.

PMX-III operates in four different main modes:

As a dosimeter, measuring dose and dose rates simultaneously.

• The PMX-III can be operated from the control room. Functions as hold, normalize, auto range, and auto reset are available. Use of light detectors or current detectors makes it possible to measure , cd/m

As a multimeter measuring kVp, time, dose, and dose rate simultaneously.

•

As a waveform analyzer

•

• Remote controlled by the oRTIgo software.

, lx , mA, and mAs.

PMX-III can be used to measure the following:

• Dose, dose rate, and dose/frame

• Light output from monitors and film viewing boxes using L100 light detector

• mA and mAs using optional current probes

Chapter

•

Mammo kVp and diagnostic kVp accuracy

•

Exposure time accuracy

•

Reproducibility of kVp, time, and output

•

mAs-linearity

•

HVL

•

kV and radiation output waveform

•

Dose rate, mA and light waveforms

•

Dose/frame, frame/s and monitor frequency (Hz) automatically using waveform analyzer

PMX-III version 6.0 can be programmed to always start up in dosimeter mode or multimeter mode or what mode was used when last powered off.

PMX-III Manual 1999-03/6.0B 7

About oRTIgo Version 3.0 INTRODUCTION

1.2 Package Information and Changes Version 6.0

Please read the addendum to the reference manual.

1.3 Options and Accessories

Please study the RTI’s product catalogue that should be included in the

Chapter

package. The latest information can be found on RTI’s web site www.rti-e.se.

1.4 Application Notes

For A list of available application notes, see chapter 9 “Notes and Reports”. All application notes can be downloaded from our web page . They are stored as pdf files.

1.5 About oRTIgo Version 3.0

This manual briefly describe oRTIgo version 3.0 in chapter 6, for detail information please study the oRTIgo user manual.

Example of dose rate waveform with automatic calculation of dose/frame and frame/s

8 1999-03/6.0B PMX-III Manual

INTRODUCTION About ADIs

1.6 About ADIs

1.6.1 What is the Function of an ADI

The ADI contains the calibration factors for the detector with the same serial number. It also informs the PMX which detector is being used and transfers data to PMX-III for optimize the use of the detector. As an example the selected ADI can inform if PMX-III should display dose rate or dose values after power on.

Chapter

ADI multi module (replaces the need for up to 5 separate R100 ADIs, option)

1.6.2 What to do when Changing an ADI

The PMX reads the ADI at power on, after each exposure in multimeter mode and when pressing Reset. The display will indicate the type of ADI. Pressing reset longer than2sindosimeter mode will make a new offset calibration. A “c” is displayed after reset to indicate calibration. Do not expose during the time “c” is displayed.

1.6.3 Any Precautions?

The ADI contains an EEPROM with the probe calibration data. The calibration data can be downloaded to your PC by the oRTIgo program delivered with the PMX. In case of deletion (Er.30 message) this data can then be restored again. Also the internal Eeprom can be restored the same way. See chapter 10 “Hints and Troubleshooting” for more information.

1.6.4 How to Choose the Correct ADI Module

See the Short form Detector Selection Guide below.

PMX-III Manual 1999-03/6.0B 9

Shortform Detector Selection Guide INTRODUCTION

1.7 Shortform Detector Selection Guide

Chapter

Type

ADI

Code

R100 8/A

R100 8/A(P1)

R100 8/A(P2)

R25 7/B

R100 8/D

L100 6/U

Beam Quality Typical Use

50-150 kV

W/23 mm Al

50-150 kV

W/23 mm Al

50-150 kV

W/23 mm Al

50-150 kV

W/3mmAl

25-35 kV

Mo/ 30m Mo

Luminance

CIE filter

film dose / rate 0,001-40 mGy/s

II dose rate input 0,03-0,46 µGy/s

II dose rate input 0,10-46 µGy/s

Skin dose / rate 0,004-160 mGy/s

skin dose to breast 0,002-90 mGy/s

Monitor adapter

Film viewing box

Typical Range

(rate)

0,1 cd>1000 cd/ m 0,5 cd>9999 cd/ m

L100 6/Y Illuminance, diffusor LUX adapter 0,25 - 4000 lx

Invasive mA & mAs

MAS-1 5

(use the mA

mA and mAs 0,10-2000 mA

test socket)

MAS-2 4

MAS-3 J

The R25 and R100 are ideal for field service situations. They do not need corrections for temperature or pressure an need no bias voltage.

Non-invasive mA &

mAs

State of the art

non-invasive mA &

mAs

mA and mAs 50-2000 mA

mA and mAs 0,10-2000 mA

10 1999-03/6.0B PMX-III Manual

INTRODUCTION Typical Use

1.8 Typical Use

(ADI=Automatic Detector Identification)

Application

Cont. fluoroscopy 3/6

DSI/spotfilm fixed

current

DSI/spotfilm falling

load

Ambient light level 6/Y Illuminance, (lx)

Skin dose

Monitor light output

with test pattern

mA, mAs, and mA

waveform check

ADI

8/A(P1) Dose rate only

8/A(P2)

8/A

7/B

6/U Luminance (cd/m

Measurements

Dose rate & dose rate

Dose rate & dose (less

sensitive)

Unfiltered beam (3mm

Al.)

with MAS-1 current

probe

Power on

Display

rate

dose

rate

dose

)

rate

dose

PMX

Display

code

8.AP1

8.A.P2

8.-A-

6.-y-

7.-B-

6.-Y-

MAS.1

Chapter

Determine dose/frame

and number/frames per

second

Determine monitor

vertical frequency

8/A(P2)

6/U

oRTIgo waveform

analyzer (see record

news1.dta)

oRTIgo waveform

analyzer (see record

news1.dta)

- Not valid

PMX-III Manual 1999-03/6.0B 11

Chapter

Typical Use INTRODUCTION

This page is intentionally blank.

12 1999-03/6.0B PMX-III Manual

DESCRIPTION OF PMX-III The Display

2 DESCRIPTION OF PMX-III

2.1 Front Panel

PMX-III is equipped with a membrane switch panel with 9 different switches, one LCD display, and 8 LED indicators,4. Each time a key is pressed a beep is generated to indicate that PMX-III has recognized the key.

Chapter

2.2 The Display

The display is a four digit LCD (liquid crystal display). The display is used to show digits and text and to indicate dose and dose rate units. Dose and dose rate are indicated at the top and bottom of the display. The character “c” in the first position indicates that PMX-III is performing internal calibrations. This is done after each exposure in multimeter mode and when RESET is pressed in dosimeter mode.

When PMX-III operates in multimeter mode and is turned upside-down the display information is automatically turned around. This function can be turned off by means of the programming feature.

PMX-III Manual 1999-03/6.0B 13

Chapter

The LED Indicators DESCRIPTION OF PMX-III

2.3 The LED Indicators

Eight LED indicators are used to indicate different parameters and modes of operation. The LED indicators are turned on each time a measurement is performed or a function is selected. In multimeter mode the LEDs are on for 10 seconds and then turned off to save power. If the LEDs are off, they can be turned on again by pressing the upper cursor key.

In dosimeter mode the LEDs are on continuously.

The following LED indicators are on the front panel:

kVp Indicates tube voltage.

sec Indicates exposure time, measured in seconds.

msec Indicates exposure time, measured in

milliseconds.

pulse Indicates exposure time, measured in pulses.

14 1999-03/6.0B PMX-III Manual

DESCRIPTION OF PMX-III The LED Indicators

Chapter

MAMMO ON: Indicates that the selected tube/fil

ter combination corresponds to a mammo X-ray unit, i.e. the MAM sensor area is used.

OFF: Indicates that the selected tube/fil-

ter combination corresponds to a conventional X-ray unit, i.e. the RAD sensor area is used.

HF ON: Indicates high frequency mode.

OFF: Indicates low frequency mode.

LOCK ON: Indicates LOCK or manual LOCK

mode.

OFF: Indicates SET mode.

PRO ON: Indicates PROGRAMMING mode

(the ON/OFF key acts as ENTER key) or that the dosimeter is acti vated.

DOSIMETER OFF Indicates multimeter measuring

mode.

PMX-III Manual 1999-03/6.0B 15

Chapter

Front Panel Keys DESCRIPTION OF PMX-III

2.4 Front Panel Keys

The front panel keys are used to choose different operating modes. The same key may have different functions in multimeter and dosimeter modes.

The following keys are on the front panel, see figure.

ON/OFF (ENTER) Power on/off and enter key in programming mode.

PARAMETER Multimeter:

ter an exposure.Dosimeter: No function.

MODE Changes operating mode

TUBE/FILTER Multimeter: Selects tube/filter combination.

Dosimeter:

F3/RESET Multimeter: Activates a setup table.

Dosimeter: Performs reset of the electrometer.

F4/DOSE Multimeter:

Dosimeter: Selects dose.

F5/RATE Multimeter: Activates a setup table.

Dosimeter: Selects rate.

Selects parameter to be displayed af

No function

Activates a setup table.

UPARR and DNARR

16 1999-03/6.0B PMX-III Manual

Select different entries when moving around in the menus.

DESCRIPTION OF PMX-III Back Panel and AMP-1

2.5 Back Panel and AMP-1

On the back panel the AMP-1 preamplifier/serial interface, there are four connectors:

Detector connector input

•

9-pin ADI connector

•

8- pin MINI-DIN serial connector

•

BNC output

•

Chapter

A BNC connector for connection to an oscilloscope or voltmeter.

PMX-III Manual 1999-03/6.0B 17

Chapter

The Battery Case DESCRIPTION OF PMX-III

2.6 The Battery Case

Two high power alkaline “6LR61” 9 V batteries should be used if battery is used. Preferable a Battery Replacement Box “BRB” for mains power could be used instead of the two batteries.

18 1999-03/6.0B PMX-III Manual

DESCRIPTION OF PMX-III Top Panel

2.7 Top Panel

On the top you will find indications for two sensor areas for MAM and RAD and indication where to place the dose detector (in multimeter mode), and user instructions for PMX-III

Chapter

PMX-III Manual 1999-03/6.0B 19

Chapter

Special Remarks for Use of ADI 8/A(P1) DESCRIPTION OF PMX-III

2.8 Special Remarks for Use of ADI 8/A(P1)

The remarks are valid for PMX-III working in dosimeter mode:

Check that the correct ADI and detector is connected and that the detector is not

• radiated during the time RESET is pressed.

Always press RESET until "c" appears, when a detector has been connected, to read

• the ADI information. PMX-III then automatically selects Range 3 and then makes a check that the correct offset level exists before the instrument is ready to measure.

A few picoampere current spike can create a doserate overflow that make the dose

• display indication show HI.SI. This situation can typically happen when the user connects or changes detector and ADI with power on, and the preamplifier circuitry at the same time is activated. Press RESET to clear. This is not seen if the user selects RATE before changing to 8/A(P1) ADI since the current spike happens only once, and when the display updates the value is back to zero again. In the new release of PMX-III version 6.0 PMX-III automatically starts up in dose-rate mode for 8/A(P1) and therefore the message HI.SI is not seen anymore.

• The offset adjustment potentiometer hole on the back is only for service purposes for detectors where the detector offset level can change dramatically between different types. This is not the case for the R100, R25, and L100 detectors. The hole should normally be sealed.

If the offset value is negative the PMX-III cannot work properly. If the offset value is to high then the measuring range value will be limited. A voltmeter have to be connected to BNC output on the back panel to be able to test the offset level correctly. Normal working levels for R100 using 8/A(P1) is between 100 and 300 mV.

A correct value is 200 ±30 mV after reset and normal working condition . (Without any ADI connected and after Reset the normal level is 100 ±20 mV.)

Only adjust the potentiometer if you are sure that the real offset level is outside the accepted range that is valid for the ADI used.

20 1999-03/6.0B PMX-III Manual

DESCRIPTION OF PMX-III Operation of Principle of the Electrometer

2.9 AMP-1 Front Panel

Chapter

2.10 Operation of Principle of the Electrometer

PMX-III Manual 1999-03/6.0B 21

Chapter

Operation of Principle of the Electrometer DESCRIPTION OF PMX-III

This page is intentionally blank.

22 1999-03/6.0B PMX-III Manual

HOW TO SET UP THE SYSTEM

3 HOW TO SET UP THE SYSTEM

Place PMX-III in the X-ray field for multimeter measurements.

•

For dosimeter measurements place the PMX-III as convenient for you as

• possible and use the 8 meter extension cable and the probe holder to put the detector in the measurement field.

If a computer is used, connect the interface cable between your PMX-III

• AMP-1 and the computer (com l or Com 2), use serial extension cable if needed.

Connect the ADI-module and detector, use detector extension cable if

• needed.

Connect the power supply to the BRB-1.

•

• Power on the PMX-III, start oRTIgo or follow instructions on top panel.

Chapter

Figure 1. Correct connection of the serial cable, the detector cable, and ADI.

PMX-III Manual 1999-03/6.0B 23

Chapter

HOW TO SET UP THE SYSTEM

Figure 2. Detail picture of connection of the serial cable, the detector cable, and ADI Multi module (option).

Figure 3. Correct connection of the serial cable, and ADI for the old serial interface.

24 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS kVp and Time (Multimeter Mode)

4 BASIC QC MEASUREMENTS

4.1 kVp and Time (Multimeter Mode)

4.1.1 PARAMETER

This key selects the measuring parameter to be displayed. Each time the key is pressed the display changes between kVp, exposure time, dose, and dose rate.

4.1.2 MODE

This key selects the type of measuring mode: SET or LOCK mode, manual LOCK mode, LF or HF mode, waveform analyzer , or dosimeter mode.

Chap

4.1.3 When to use SET and LOCK modes

SET basic measuring mode (>50 ms exposure times).

LOCK- kVp and time measurements for short exposure

times. (See also manual LOCK mode)

Two exposures must be done when using LOCK Mode. One to set PMX gain and range and one to get the values.

Chapter

Use LOCK Mode to

•

Study the beginning of the exposure waveform using the BNC output

•

Measure exposure time by counting pulses.

PMX-III Manual 1999-03/6.0B 25

kVp and Time (Multimeter Mode) BASIC QC MEASUREMENTS

4.1.4 When and how to use manual LOCK mode

Chapter

When it is impossible to make a set exposure because of too short

• exposure time.

When the user wants to control how PMX-III selects kV-range and gain:

•

Press DNARR to select between:

F1:G1 to F1:G4 - F2:G1 to F2:G4

F1= kV range 45-90 kV F2= kV range 85-155 kV G1= Very low X-ray output G2= Low X-ray output G3= Average X-ray output G4= High X-ray output

The electrometer always uses range rA:3 .

4.1.5 When to use LF and HF:

LF - single phase

- three phase 6-pulse

- 12-pulse, DC, and mammo units

- HF > 5 kHz and ripple less than 5 %

- Most modern DC/DC X-ray units.

HF - 0.8-5 kHz, only when ripple>5%.

The analog output bandwidth for PMX-III is 800 Hz in LF mode and 10 kHz in HF mode.

26 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS kVp and Time (Multimeter Mode)

4.1.6 TUBE/FILTER

This button selects valid calibration tables for different tube/filter combinations.

Up to 16 different calibration tables can be selected. 1-4 are dedicated for the diagnostic 45-155 kV range. 5-12 are dedicated for mammo use. 13-16 for CT.

Calibration table numbers which are stored into PMX-III are indicated after the text CA in the display (Ex. CA -1). Use cursor keys to select correct tube/filter combination from the existing calibration table. Store with the ENTER key.

F3, F4, and F5.

Factory set function keys for direct setup of measuring conditions. The keys can also be user defined.

y+F3

Press UPARR and while still pressing UPARR, press F3, use cursors to select delay 0-9999 ms.

Press ENTER to store the new value.

Chapter

PMX-III Manual 1999-03/6.0B 27

kVp and Time (Multimeter Mode) BASIC QC MEASUREMENTS

4.1.7 Measurement with the MAM/RAD version

Connect the dose detector/ADI module.

•

Each ADI module holds information for one beam quality only (See also

• the “Detector Selection Guide” chapter 9 if you need additional help).

Power on PMX-III. The “DOSIMETER” indicator must be off. If the

• indicator is on, press the MODE key and enter “MuLt”.

Choose a calibration table with the TUBE/FILTER key, or press a

• function key to upload a setup table.

Position the sensor area (MAM or RAD) in the X-ray beam, and

• collimate the light field.

Put the dose detector on top of the PMX-III, and add desired additional

• filtration.

Chapter

• Set desired generator values and make an exposure.

• Read the measured values from the display.

• After the results have stopped flashing, and the character “c” has disappeared, PMX-III is ready for another exposure.

• Press the PARAMETER key to alter between kVp, exposure time, dose, dose rate, or light.

28 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS kVp and Time (Multimeter Mode)

4.1.8 Default values for F3-F5 (MAM/RAD version)

F3 Setup table #1; (CA:1 diagnostic)

W/Al 3.0 mm, 45 - 155 kV

F4 Setup table #4; (CA:5 mammo)

Mo/Mo 30 um, 23 - 35 kV)

F5 Setup table #5; (CA:6 mammo)

Mo/Al 2.0 mm, 30 - 46 kV

Setup table #1 is always uploaded when the PMX-III is powered on.

4.1.9 CT kVp Measurement with the CT/RAD version

Power on PMX-III. The “DOSIMETER” indicator must be off. If the

• indicator is on, press the MODE key and enter “MuLt”.

• Choose a calibration table with the TUBE/FILTER key, or press a function key to upload a setup table.

• Press F4 or F5 according to the table below:

• F4 Setup table #13; (CA:13 CT without comp.filter) W/see calibration record,75-145 kV

• F5 Setup table #14; (CA:14 CT with comp.filter) W/see calibration record, 75-145 kV

Chapter

PMX-III Manual 1999-03/6.0B 29

kVp and Time (Multimeter Mode) BASIC QC MEASUREMENTS

Open the beam width to 10 mm. Use the patient positioning light to

• align the CT sensor area horisontally within the beam.

Disable the motion of the tube and table. Place the tube in the top

• position.

Make the exposure, both kVp and time will be displayed after the

• exposure is finished. Use the PARAMETER key to select kVp and time.

Make corrections of the kVp value for the filtration dependence if

• needed,

Consult the PMX-III reference manual, Appendix E for more information how to correct for filtration depencence and how to make kVp measurements with rotating CT units and oRTIgo

Chapter

30 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS Dose and Dose Rate (Dosimeter Mode)

4.2 Dose and Dose Rate (Dosimeter Mode)

PMX-III is normally supplied with two small durable and accurate solid state detectors for X-ray and light measurements, and a number of ADI modules.

(See the “Detector Selection Guide; Chapter 9” if you need additional help.)

In dosimeter mode dose and dose rate are measured simultaneously. Press the DOSE key and the measured dose value is displayed. Press the RATE key and the measured dose rate is displayed. Rate is indicated on the display with a “:” sign.

MODE The MODE key is used to select manual LOCK,

free run, or trig level, or return to multimeter mode.

Chapter

PMX-III Manual 1999-03/6.0B 31

Dose and Dose Rate (Dosimeter Mode) BASIC QC MEASUREMENTS

4.2.1 When and How to Use Manual LOCK Mode

Press DNARR to manually select electrometer range if manual LOCK mode is selected:

RA:1 This is the most sensitive range for low dose rate

measurements.

RA:2 Middle range.

Chapter

RA:3 This range should be used for high dose rate mea

surements.

It is recommended to use the manual LOCK mode when the exposure time is less than 50 ms.

Press MODE , select Auto to select auto range.

4.2.2 How to Use Free Run/Trig Mode

In the free run mode no trig levels exist. This makes it possible to measure down to zero signal in the display. In trig run mode, measured dose rate value is started to be displayed when the signal is above a set trig level determined by the selected ADI. Please note that PMX-III is not powered down automatically when “Free run” is activated.

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BASIC QC MEASUREMENTS Dose and Dose Rate (Dosimeter Mode)

4.2.3 Active Keys

DOSE Press to read measured dose in specified

dose unit.Press again to display dose unit.

RATE Press to read measured dose rate value

in specified dose unit. Press again to display dose unit.

RESET Press <1 s to reset display to zero.

Press >1 s for internal zero-adjustment.

The ADI code X.-Y- where X= Detector identification 1, 2, 3 .6.7.8 .. and Y= Beam quality A, b, C, d, U,Y. is displayed for 1 s to indicate valid ADI.

The ADI code for AMP is XY.PZ where X and Y is defined as above . P indicate AMP-1 Z =1 for range 1 , Z=2 for range 2

y+MODE Press to normalize the display value to a prede-

fined value. Can be used to calculate a ratio between two detector signals. Abort normalize mode by pressing y+MODE again.

y+RESET Press to toggle between manual and auto-

reset modes. Manual: Dose values are accumu lated Auto: Previous dose value is cleared

y+DOSE Press to hold display value. Abort by pressing

y+DOSE again.

Chapter

PMX-III Manual 1999-03/6.0B 33

Dose and Dose Rate (Dosimeter Mode) BASIC QC MEASUREMENTS

y+RATE Press to select the dose/frame menu:

Use the cursor keys to select:

1.5-63.5

Chapter

OFF Normal dose and dose rate measurement

Fr Selects the frame mode.

Press ENTER and current number of frames during the exposure is shown in the display. Use the cursor keys to select a new value. Press ENTER to store the new value,measuring mode is activated again.

The measured and displayed dose is divided with the number of frames.

Fr.: Selects the frames/second mode.

Press ENTER and current number of frames dur ing one second is shown in the display. Use the cursor keys to select a new value. Press ENTER to store the new value, measuring mode is activated again.

The measured and displayed dose rate is divided with the number of frames/s.

It is recommended to use the manual LOCK mode when using the frame mode.

An alternative method is to use the waveform analyzer and oRTIgo. The number of pulses, number of frames/s or Hz, and dose/frame are automatically calculated from the stored dose rate wave form.

34 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS Dose and Dose Rate (Dosimeter Mode)

4.2.4 How to Make a Measurement

Connect the dose detector/ADI module.

• Each ADI module holds information for one beam quality only.

Power on PMX-III. The “DOSIMETER” indicator must be on. If the

• indicator is off, press the MODE key, scroll with the cursor keys and select “dOSI” with the ENTER key.

Position the dose detector in the X-ray beam.

•

Set desired generator values and make an exposure.

•

• Read measured values on the display. Both dose rate and dose value are stored after the exposure.

Chapter

PMX-III Manual 1999-03/6.0B 35

The Waveform Analyzer BASIC QC MEASUREMENTS

4.3 The Waveform Analyzer

It is strongly recommended to use oRTIgo to collect waveform if possible since it is much easier to handle. If used without computer it is recommended to read sections 6.1 to 6.3 in the reference manual at least once before using the analyzer:

Chapter

Connect a BNC cable between the connector on the rear of the PMX-III

• and your oscilloscope (amplification: 0.5 V/div, time: 5 ms/div).

Use the MODE key to enter the mode menu and be able to switch the

• waveform analyzer on and off.

The waveform analyzer has three main levels indicated on the display:

•

“Set”: All PMX-III keys are valid. The PMX-III waits for an exposure to adjust gain and filter to current generator settings.

• “SAMP”: Waiting for an exposure. Gain and filter adjustment are set from an earlier exposure or by the user if manual lock mode is selected. The PMX-III samples the detector to be able to measure the initial part of the exposure.

“PA:1":

Sending sampled kV and radiation waveforms to the oscilloscope.

“RY:1”: Sending sampled electrometer and radiation waveforms to the oscilloscope

•

Make exposures, and the PMX-III automatically adapts to the measurement situation.

•

Use the:

-PARAMETER key to toggle between kV and radiation or electrometer

waveforms.

-cursor keys to select different memory parts of the measured exposure.

-F3 key to calibrate the kV or electrometer rate waveform on the

oscilloscope.

-ENTER key to go to “SEt” level.

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BASIC QC MEASUREMENTS The Waveform Analyzer

Please consult Section 6.3.2 and 6.5 in the reference manual to use the programming features.

4.3.1 Examples of waveforms

Dose rate response from a dental unit at two bandwidth 60 kV, 3 mA, 23 mm Al, SSD=30cm, 8/A(P2) 45 Hz and 1 Hz are selected using the AMP-1 filter knob.

Chapter

Upper: Dental kV, compressed mode Lower: Dental output, simultaneously sampled

PMX-III/PH Manual 1999-03/6.0B 37

The Waveform Analyzer BASIC QC MEASUREMENTS

4.3.2 Waveform flowchart

Sa mp lin g ra te

Chapter

The flo w c ha rt is va lid for PMX-III firmware 6.0

Wa v f lo w 4 . c d r

38 1999-03/6.0B PMX-III/PH Manual

BASIC QC MEASUREMENTS Using preamplifier AMP-1

4.4 Using preamplifier AMP-1

AMP-1 consists of a preamplifier for the PMX-III electrometer and a serial interface. See Chapter 2 for an overview of the AMP-1 functions.

AMP-1 makes it possible to increase the sensitivity 100 times when used with PMX-III. This sensitivity is needed for acceptance test and adjustment of modern Image Intensifier systems.

AMP-1 should only be used with the PMX-III in Dosimeter mode.

The AMP-1 is specially designed to measure the very low entrance dose rate levels to an Image Intensifier (II). An optimised range for II of 0.030 µGy/s to about 46 µGy/s is obtained when the detector R25/R100 is used together with AMP-1. The preamplifier is simply “piggy backed” directly on the PMX-III back panel, eliminating connecting cables. The AMP-1 is powered by the PMX-III.

Furthermore there is no need to disconnect the AMP-1 and the detector from PMX-III since the AMP-1 only is activated when a special made AMP-1 ADI is used. The special AMP-1 ADI (Automatic Detector Identification) combines the features of storing the detector data in use into the ADI and simultaneously activate and select range of the AMP-1. The AMP-1 has two measurement ranges, P1 and P2.

AMP-1 has a built-in second order low-pass filter with two ranges, DC-1 Hz and DC-45 Hz.

Chapter

The special ADI connected to the AMP-1 makes it possible to read directly in µGy/s (or µR/s) and µGy (µR) on the display depending on AMP-1 range and detector. The II dose rate waveform can also be collected and displayed using the oRTIgo wave form analyser or with an oscilloscope. A handy method to adjust the II entrance dose rate level (typically 0.10-0.50 µGy/s) is to look at the dose rate level with an oscilloscope. The scale factor is 1 µGy/s / V, if the AMP-1 and R100 is used and the oscilloscope is connected to PMX-III BNC output.

PMX-III Manual 1999-03/6.0B 39

Using preamplifier AMP-1 BASIC QC MEASUREMENTS

Example:

The picture below shows a measurement with a dose rate of 0.13 µGy/s ocilloscope settings: 0.05 µGy/s /div. 1 s/div.

Chapter

Using oRTIgo a certain portion of the dose rate waveform can be selected using the radiation waveform as reference. This part of the dose rate waveform is then integrated and the dose/frame, dose rate value and number of frames/s value is automatically calculated and displayed.

40 1999-03/6.0B PMX-III Manual

BASIC QC MEASUREMENTS Measurements with the AMP-1

4.5 Measurements with the AMP-1

4.5.1 General

It is recommended that only dosimeter mode is used with the AMP-1. Select reading in dose rate by pressing the RATE knob.

Be aware that the limited bandwidth of 1 Hz is optimised for Image Intensifier measurements measuring the dose rate signal. If pulsed fluoroscopy should be measured you must select higher bandwidth. Select range 2 and 45 Hz or deactivate the AMP-1 to get 700 Hz bandwidth to be able to follow the individual pulses.

The PMX-III starts to measure when the dose rate signal is greater than approximately 0.050 µGy/s when using the AMP-1 8/A(P1) ADI (0.030-4.600 µGy/s for R100).

Select “Free” run mode if the AMP-1 should start to measure all the way from zero.

For short exposure times or pulsed radioscopy please deactivate the AMP-1 by selecting the appropriate ADI and select multimeter mode or use the waveform analyzer to be able to measure the individual dose rate pulses. When selecting multimeter mode you should and must “gate” the dose rate signal by using the PMX-III kV detector as a trigger. This method makes the measurement easy to do. You can even combine the dose rate and dose reading with kVp and exposure time measurements.

Chapter

PMX-III Manual 1999-03/6.0B 41

Measurements with the AMP-1 BASIC QC MEASUREMENTS

4.5.2 Detector Range and Identification Codes

On the above display the colon indicates that rate mode is selected.

As long as the RATE key is pressed, the sign above µGy/s is shown to indicate that the unit is µGy/s. The reading is 0.278 µGy/s. The measuring range and unit is indicated on the ADI.

Chapter

An identification code for the selected conversion factor is shown during approximately one second after reset and zero adjust.

X.-Y- Standard ADI, for detector X and beam quality Y.

XY.PZ AMP ADI, for detector X, beam quality Y,

range Z (1 or 2).

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SERVICE / MAINTENANCE Introduction

5 SERVICE / MAINTENANCE

5.1 Introduction

The default function of PMX-III was earlier to start up with Multimeter or Dosimeter mode, depending on the mode used when it was powered off. This is sometimes inconvenient, especially when having specific written instructions for certain measurements. You can now program the PMX-III to start up in either Multimeter or Dosimeter mode. You activate this function by pressing the MODE and ENTER key when choosing the measuring mode you want to be default after power on. It is done in the following way:

Activate the measuring mode, Multimeter or Dosimeter, you don’t want to have as

• default. Use the MODE menu if you have to change measuring mode.

• Press MODE to activate the MODE menu.

• Move to the entry corresponding to the mode you want to have as default, i.e. “Mult” or “dOSI".

• While keeping the MODE key pressed, press the ENTER key.

• Release both keys.

The PMX-III will now start up with the measuring mode you selected.

To disable the above described function:

• Press the MODE key.

•

Move to the entry End.

•

While pressing the MODE key, press Enter.

5.1.1 New Version of Firmware for PMX-III.

•

Automatically selects dose rate when ADI 7A(P1) or 7A(P2) is detected

•

All dose rate measurements with ADI 7A(P1) and 7A(P2) will be displayed in the same unit (µGy/sec or µR/sec )

•

The measured dose rate is "freezed" in the display until a new exposure starts or reset is pressed (not in Free Run mode, without trig level)

Chapter

•

Possibility to select half of frame number, for example 12.5 (consequently the maximum value will be 63.5 instead of 125)

•

The Hi-YES-Lo message related to the offset adjustment (when AD 7A(P1) is used) is removed (see: "Offset potentiometer" chapter 2)

PMX-III Manual 1999-03/6.0B 43

Introduction SERVICE / MAINTENANCE

5.1.2 Extension Cable.

An extension cable (8m) connected to the R25/R100 probe enables the engineer to position the PMX-III at a conve nient place (i.e. near to control desk in control room of the PMS system). This makes PMX-III frontpanel operation and reading of the display eas ier during testing. Furthermore the engineers radiation load is kept as low as possible. Avoid work near the radiation field.

Chapter

5.1.3 Probe Holder.

The R25/ R100 probe is attached to the probe holder. This support makes positioning of the probe in the X-ray beam much more easy (i.e. in Scopomat). It also prevents the probe to rotate by the force of the cable which can result in consid erable measuring inaccuracy.

5.1.4 ADIs Removed from Detector Cables.

Since there are too many ADIs connected to the cable-chain of the detector cables (both R100 and L100) they are removed and stored in a separate storage area in the case.

5.1.5 Maintenance.

In order to prevent damage to the probes during trans port a protection cover is supplied with the R25/R100 dose probe and L100 light probe.

44 1999-03/6.0B PMX-III Manual

SERVICE / MAINTENANCE Entrance Dose Rate Measurements

5.2 Entrance Dose Rate Measurements

5.2.1 Very Low Entrance Dose Rate to an Image Intensifier

See also on top of PMX-III for a very short instructions

Put 20 mm Al or equivalent copper filter (appr. 1.4 -2.1 mm Cu plate) to

• simulate a patient thickness. Use the probe holder to fixate the R100 so it is easy to move it over the II input area. Place it on the II so that is not affecting the feedback system. As a guideline, do not place the detector in the centre of the field, rather somewhere near a circle with half the the diameter of the field diameter.

Use the EXT-1 extension cable if needed.

•

Select high dose rate bandwidth with the little tiny red button on the rear

• panel (the button should be “out”

• For continuos fluoro select ADI 8/A (P1) The range is now 0,030-4,600 µGy/s and the reading is directly in µGy/s, on the PMX-III.

For pulsed fluoro measurements select 8/A (P2) The range is now 0,1-46 µGy/s range instead and also the higher bandwidth (DC to 45 Hz).

• Power on PMX-III and select free run mode (see section 2.3), then select RATE. By selecting free run mode PMX-III deactivates the trig level so the user is able to measure all the way down to zero .

•

Verify by pressing RESET that the correct ADI is selected.

•

Start the fluoro exposure. The dose rate is updated on the display during the exposure. You can freeze the display during the measurements using the hold mode, see Chapter 4 but since the display values are stored after the exposure both for dose rate and dose there are normally no need to use this function anymore. Pressing the RATE button during or after the measurements displays the measuring unit.

Chapter

Note: Other detectors and measuring units are also supported. In this chapter the dose detector R100 and use of Gray units have been used. See Chapter 9 and the Shortform Detector Selection Guide for use of other units.

PMX-III Manual 1999-03/6.0B 45

Entrance Dose Rate Measurements SERVICE / MAINTENANCE

Hints:If the dose rate output also needs to be monitored during adjustment, please connect an oscilloscope to the PMX-III BNC connector. Select 100 mV/Div. and 1s/Div. on the scope. A change of the dose rate of 0.1µGy/s is then equal to 1 Div. on the y-axis. The bandwidth is approximately 1 Hz or 45 Hz.

Chapter

Dose rate measurement on II fluoro system with PMX-III/AMP-1.

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SERVICE / MAINTENANCE Entrance Dose Rate Measurements

5.2.2 Hints

Use the probe holder

• together with R25/R100 to be able to place the detector in a suitable place on the II input screen. By observing the dose rate measured during slow movement of the detector above the II you can check if the detector is altering the feedback system or not.

Use the “free” run mode in

• dosimeter mode to deactivate the internal trig level. This makes it possible to measure linearly all the way down to

The R100 on rod in image intensifier field.

the display reading will not suddenly change to zero or freeze.

zero in the display. It is therefore easier to adjust small dose rate values since

• If no dose rate can be measured, please check that the current is greater than 0.05 µGy/s or select “free” run mode.

• The AMP-1 can be mounted all the time on the PMX-III. The AMP-1 is only activated when the special ADI that “power on” the AMP-1 mechanically is used. When a normal ADI is used the current signal is passed directly to the PMX-III electrometer input without using AMP-1’s signal amplification.

•

Use the 8 meter extension cable EXT-1 to be able to place PMX-III in the control room for easy readout and change of ADI.

•

Use the BRB-1 and AC/DC adapter to avoid battery drain.

•

Select “free” run mode to avoid PMX-III to power off. It is recommended to use BRB-1 in this situation.

•

Use High bandwidth (45 Hz)allways if possible .

•

Test have been done with R100 8A(P2) 45 Hz on pulsed fluoro/dental system indicating that measurements with pulse rate of up to approximately 30 pulses/s can be measured.

•

The AMP-1 ADI automatically selects gain 3 on PMX-III electrometer. This is indicated by the “Manual Lock” LED. Trying to use gain 1 or gain 2 easily result in a"HI.Si" message.

Chapter

•

If problems should appear with the serial communication transfer, please check that the PMX-III BRB power supply and the computer power supply is connected to the same power outlet.

PMX-III Manual 1999-03/6.0B 47

Fluoroscopy low mA SERVICE / MAINTENANCE

5.2.3 Example of Dose Rate Waveforms

An oscilloscope was connected to the analog output of the PMX-III.

The external detector R100 was placed in the X-ray field so dose rate waveform could be collected using the PMX-III waveform analyzer. Only the dose rate waveform was displayed on the oscilloscope. 100 nGy/s was measured. (50 nGy/s/div and 1s/div)

Chapter

5.3 Fluoroscopy low mA

5.3.1 II-Entrance Dose Rate (µGy/s)

• Connect dose detector R100 and ADI 8/A(P1) to the input on the rear panel of the PMX . Make sure that the range 1 or 2 switches are correctly depressed.

•

Select high bandwidth with tiny red button (pull out) on rear panel.

•

Add 1.5 mm Cu or 20 mm Al filtration.

•

Power on the PMX and wait until the internal checks are completed.

•

The dosimeter LED should be on now and PMX-III is ready to measure dose rate. A “:” in the middle of the display indicates that dose rate is selected (1).

•

Press select Free run with the cursor keys, and press Enter to activate “Free”run mode.

•

Give fluoroscopy command, wait for stable reading.

•

Read desired value during or after the exposure

•

The unit of measurement is shown when pressing or .

48 1999-03/6.0B PMX-III Manual

(2)

SERVICE / MAINTENANCE Exposure Dose

(1) The lower third dot indicates the deciml dot !

(2) y+RESET

Press to toggle between manual and auto reset modes. Manual: Dose values are accumulated Auto: Previous dose value is cleared

y+DOSE

Press to hold display value. Abort by pressing y+DOSE again.

Note: If the display indicates a dash (-) or (Hi Si) ,then press reset longer then 1 second until c appears and now PMX corrects for internal zero-adjustment., It is normal that the display still indicates a dash(-) after reset sometimes if the drift is slightly negative.

5.4 Exposure Dose

5.4.1 Fluorography and Radiography

• Connect dose detector R100 and ADI for: Falling load ADI: 8A Fixed current ADI: 8A(P2) (1)

• Select high bandwidth by releasing the tiny red button on the rear panel.

• Add 1.5 mm Cu or 20 mm Al filtration.

•

Select an appropriate exposure time >=50 ms (2)

•

Power on the PMX and wait until the internal checks are completed, this means the dosimeter LED is on.

•

Make a single exposure Both the measured dose and dose rate value have been collected and are

available on the display. Use or to move between measured rate or dose value. By holding down the same key the unit of measurement is indicated.

Chapter

(1) In case of Hi Si display code, take the less sensitive ADI 8A (2) If exposure time is less than 50 ms, program manual lock mode. (Section 4.2)

PMX-III Manual 1999-03/6.0B 49

Measurement of kVp SERVICE / MAINTENANCE

5.5 Measurement of kVp

5.5.1 Long Exposure time, Skin Dose, and Dose Rate (SET MODE)

Connect dose detector R25 and ADI 7/B (this means no extra filtration

• in the beam) to the input on the rear panel of the PMX .

Power on the PMX and wait until the internal checks are completed, this

• means the character “c” has disappeared.

If dosimeter LED stays on after power on, press Mode. The display

• shows “M.LO”. Select “MuLt” with the cursor keys and press Enter to activate multi meter mode.

Place dose detector on the velcro strip on top of the PMX and position it

• in the beam.

Chapter

• Select for the RAD sensor area a beam quality of 3 mm( ADI:8/B)

• Set kVp, mA.

• Exposure time (1) may be as low as: 50 ms for good kV measurement. 10 ms for good exposure time measurement.

• Make an exposure.

• Read the values which are displayed automatically in the following sequence: kVp time unit for dose(rate) skin-dose(rate)

“c” indicating auto reset performed after each exposure

After this the display returns to one of the values measured .

Press PARAMETER button to scroll measured values.

Note: collimate X-ray field to protect the AMP-1 module at rear of PMX against direct radiation! It is important to irradiate the complete RAD field on top of the PMX.

Note: If the total filtration is not 3.0 mm Al, measured kV should be corrected to achieve maximal accuracy, see chapter 7.

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SERVICE / MAINTENANCE Measurement of kVp

5.5.2 Short Exposure Time, Skin Dose and Dose Rate (MANUAL LOCK MODE)

Select manual LOCK mode, in

• this mode the internal filter and gain range combination are user selectable.

Make an exposure.

•

Exposure time

•

may be as low

(1)

as: 3 ms for good kV measurement.

0.3 ms for good exposure time measurement.

In case of over- or under flow the

• default filter/gain combination for PMX is not correct.

• Press DNARR to select between:

F1:G1 to F1:G4 F2:G1 to F2:G4

F1= kV range 45-90 kV F2= kV range 85-155 kV G1= Very low X-ray output G2= Low X-ray output G3= Average X-ray output G4= High X-ray output

Chapter

The electrometer always uses range rA:3 .

(1) Exposure times are specified for HF and DC generators, for 12 pulse (or lower) generator types see Reference manual page 7-4

If you only want to use the PMX-III as an exposure timer, you can select a display mode (disp) and parameter (Par) that only display the exposure time after each exposure, see reference manual chapter 4 section 4.9.4.

PMX-III Manual 1999-03/6.0B 51

Light Measurements, Detector and Adapters SERVICE / MAINTENANCE

5.6 Light Measurements, Detector and Adapters

5.6.1 Introduction

For more general information about light measurements a separate L100 manual can be ordered from RTI Electronics AB

L100

The L100 detector is the fundamental part of the light meter system from RTI Electronics AB. On top of the actual detector a filter house is attached. This is shown in below. The filter house contains the CIE filter that makes the silicon chip have the same response as the human eye. The purpose of the filter house is also to fit the different adapters that make the L100 measure the desired quantity. The actual L100 without any adapters is not calibrated for any quantity.

Chapter

The basic L100 detector which include the CIE filter house

Monitor Adapter

The monitor adapter is intended for luminance measurements on CRTs and film viewing boxes, i.e. to measure cd/m², and it is referenced to as L100-M. It consists of two parts: a metal tube with a light shutter and an ambient light shield made of rubber. This is shown on next page. A luminance meter must have a limited field of view. In the case of L100-M this is accomplished by

pressing the tube against the surface to be measured.

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SERVICE / MAINTENANCE Light Measurements, Detector and Adapters

The purpose of the ambient light shield is to prevent non-wanted light to interfere with the measurements. This could otherwise be a problem when measuring on not so bright sources like e.g. a CRT. Without the ambient light shield non-wanted light, e.g. from the room, would be reflected via the glass surface of the CRT and would be added to the measured light. A smaller shield is also included to make the easier to position the monitor when the

ambient light level is not a big error source.This is also a part of the reason why RTI Electronics AB has chosen not to design a traditional luminance meter, with optics that let you measure at a distance. Such a measurement would obviously be a measurement of not only the source itself but also of the ambient light reflected by e.g. the

The monitor adapter with light shutter and ambient light shield..

glass surface of the CRT.

Chapter

Lux Adapter

To measure illuminance the detector must be able to collect light from every direction in a half sphere. The contribution from an incidence light beam must follow the cosine function. This is quite natural if we consider how we apprehend the surface of a spot on e.g. a desk. Seen from above at an

incidence angle of 0° the projected area of the spot is the same as the real one. When we increase the angle of incidence to 60° the projected area decreases by a factor of 0,5, just like cosine 60° equals 0,5. When we have increased the angle of incidence to 90° we of course cannot see the spot, just as cosine 90°

equals 0.

In theory this sounds easy but in practice there are a few things to consider when designing a lux detector.

53 1999-03/6.0B PMX-III Manual

Chapter

Light Measurements, Detector and Adapters SERVICE / MAINTENANCE

First: The surface of the silicon chip will always be shiny. This means

• that light that hits the detector from a very large angle of incidence will be reflected by the surface of the silicon chip, thus neglecting the cosine function.

Second: The actual silicon chip can in most cases not be placed at the

• surface of the detector. An example of this is the L100 with its CIE filter.

The solution to these problems is the lux adapter, see figure below. The white plastic inside the aluminium is called a cosine diffuser.

The surface of the cosine diffuser is, as the name implies, diffuse. Thus preventing light with a large angle of incidence from being reflected by the surface. The cosine diffuser also leads the light down to the silicon chip, more or less in the same way as an optical fibre can

The Lux adapter with its cosine diffuser

lead light. The lux adapter is referenced to as L100-L.

Collimator Adapter

The collimator adapter is a piece of plastic witha1mmhole, and it is referenced to as L100-C. Its purpose is to allow you to check the contrast ratio of the edge of the collimator light field. You measure the “light level” just inside the edge of the light field and divide this value with the “light level” outside the edge of the light field. This ratio should be sufficiently large.

Since this is a relative measurement there is no need to define what the quantity “light level” means. You simply measure the current that the L100-C produces. This also means that there is no need for a calibration of the collimator adapter.

Contact RTI Electronics AB for further information about the collimator adapter.

PMX-III Manual 1999-03/6.0B 54

SERVICE / MAINTENANCE Light Measurements, Detector and Adapters

5.6.2 Measurement of Luminance (cd/m²)

Connecting the L100-M to the PMX-III

Follow these steps to prepare a measurement.

If it is not already done, attach the monitor adapter tube to the detector

• housing. It is important that the monitor adapter is pressed all way down in the detector housing when the screw fixate the tube.

Connect the light detector L100-M to the input on the rear panel of the

• PMX-III.

Connect the Monitor Adapter ADI module marked 6/U to the connector

• on the rear panel of the PMX-III

Power on the PMX-III and select DOSIMETER mode, then choose

• RATE mode. That is normally done automatically for firmware 6.0 and later.

Make an Reset

•

You have to perform a reset before you can start to measure. It is VERY IMPORTANT that no light reaches the detector during the

reset procedure. To ensure that the instrument is reset while the detector is held in complete darkness you must press the light detector to a completely black surface, e.g. the surface of the ambient light shield, while pressing the reset key on the instrument. With the new monitor adapter with light shutter this is a easy task since the monitor adapter signal is zero until the shutter knob is pressed down. To perform a reset (actually a zero level adjustment) on the PMX-III you have to:

•

Press the reset key and keep it pressed until the character “c” is shown on the display.

•

Wait until the character “c” has disappeared.

•

Start to measure Move the light detector to the measuring point and open the shutter by pressing the knob to stop, hold to collect a light value. After you have released the knob, the PMX-III is stored the value in the display until next measurement.

Chapter

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Light Measurements, Detector and Adapters SERVICE / MAINTENANCE

5.6.3 Measurements on CRTs and Film Viewing Boxes

Attach the ambient light shield to the monitor adapter. You can select between a small and big shield. Place the light detector on the CRT or the film viewing box. Make sure the ambient light shield is held flat on to the surface to prevent ambient light from reaching the detector. Press and hold the shutter knob. Read the value on the display of the instrument. Two sample measurements are shown in below.

Chapter

Checking the luminance of a monitor, in this case different grey-level areas.

SMPTE Test Pattern

A common test pattern used when testing CRT is the test pattern specified by the Society of Motion Picture and Television Engineers, SMPTE. This test pattern has, among other features, 11 different areas of grey-scale intensity, ranging from0%to100%.

PMX-III Manual 1999-03/6.0B 56

SERVICE / MAINTENANCE Light Measurements, Detector and Adapters

When measuring on these different grey-scale areas you should have in mind that the luminance of an area NOT is proportional to its grey-scale value.

Instead the luminance (L) is related to the grey-scale level (G) by:

L ∝ G

(Equation 1 )

Equation is equivalent to:

log(L) = γ log(G) + C (Equation 2 )

In equation 2, C is a constant and γ is the gamma value of the monitor that

characterises the relationship between luminance and grey-scale value.

5.6.4 Ambient Light and Other Sources of Error

As mentioned above ambient light will strongly affect the measurement if it is not taken care of in an appropriate way. To examine how much the ambient light effects the measurements you could perform a simple experiment and measure without the ambient light shield. Measure on a CRT that is completely black, i.e. not powered on, and compare the result with measurements performed with the ambient light shield attached. Also measure with and without reduced room illumination. You will notice that the values achieved without the ambient light shield and with normal room illumination differ considerably from the ideal value. Imagine the percentage error you would achieve if you were to measure in this way on the 10 % grey-scale area!

Chapter

Other sources of error are fingerprints and dust on the CRT. Investigations have shown that these smudges can decrease the luminance by as much as 10 %.

If the CRT is not sufficiently warmed up the luminance can vary during the measurements. Some monitors need several hours to stabilise. Even if the monitor has stabilised its output luminance will vary over different areas of the surface. To exclude this error source from your grey-scale measurements you can perform the measurements from the same location on the screen. Zoom the test pattern as large as possible and pan the selected grey-scale area to the centre of the screen. If necessary you can mark the place to put the ambient light shield with a piece of adhesive tape. The tape must of course be placed in such a way that it does not affect the measurements.

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Light Measurements, Detector and Adapters SERVICE / MAINTENANCE

Chapter

Example of very compact monitor test system based on oRTIgo.

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SERVICE / MAINTENANCE Light Measurements, Detector and Adapters

5.7.3

Measurement of Illuminance (lx)

Follow these steps to prepare a measurement.

If it is not already done, attach the lux adapter tube to the detector

• housing. It is important that the lux adapter is pressed all way down in the detector housing when the screw fixate the lux adapter.

Connect the light detector L100-L to the input on the rear panel of the

• PMX-III

Connect the LUX Adapter ADI module marked 6/Y to the connector on

• the rear panel of the PMX-III.

Power on the PMX-III and select DOSIMETER mode, then choose

• RATE mode. That is normally done automatically for firmware 6.0 and later.

Make a reset

•

You have to perform a reset before you can start to measure. It is VERY IMPORTANT that no light reaches the detector during the

reset procedure. To ensure that the instrument is reset while the detector is held in complete darkness you must press the light detector to a completely black surface while pressing the reset key on the instrument.

To perform a reset (actually a zero level adjustment) on the PMX-III you have to:

• Press the reset key and keep it pressed until the character “c” is shown on the display.

•

Wait until the character “c” has disappeared.

•

Start to measure Remove the light detector from the black surface , place the detector where you want to measure and read the value on the display.

Chapter

PMX-III/PH Manual 1999-03/6.0B 59

Examples of Field Measurements SERVICE / MAINTENANCE

5.7 Examples of Field Measurements

5.7.1 Check the total Contrast Range for the System, From the Image Intensifier to the Monitor.

Setup:

Chapter

Grid mounted

Table-top mounted

SID grid mark ±1 cm

1,5 mm Cu on the X-ray collimator

Contrast phantom is placed in front of II covering the whole entrance screen.

Light is measured on the monitor with the L100 light monitor adapter.

Measuring Results:

Measuring

Field

Phantom

II=17 cm

A1 2,2 3,0 2,7

A2 3,5 4,2 4,0

A3 4,8 5,5 5,4

A4 10,3 10,6 10,7

A5 23,3 22,2 19,9

A6 47,1 49,7 47,8

A7 92,7 98,7 92,5

Continuous

fluoro

IQ APR Low

(cd/m²)

Pulsed fluoro

IQ APR

Normal

(cd/m²)

Exposure

IQ APR

25 frames/s

(cd/m²)

A8 144,6 155,7 144,6

A9 222,6 240,5 221,5

A10 279,5 281,0 273,0

Centre 28,3 28,4 28,7

Continuous fluoro

Measuring field number

Monitor adapter with light shutter to simplify the collecting of the luminance values to PMX-III and oRTIgo.

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SERVICE / MAINTENANCE Examples of Field Measurements

5.7.2 Check that the Dose and Dose Rate Level is within Specification for all II Formats.

Setup:

Grid not mounted

Table-top mounted

SID grid mark ±1 cm

2.0 mm Cu on the X-ray collimator

R100 detector is placed in front of II outside measuring field.

Please make kV and Cu correction according to calibration record.

Measuring results

ADI 8/A(P1) 8/A(P2) 8/A

II Format

Continuous fluoro IQ APR

Low

(µGy/s)

Pulsed fluoro IQ APR Normal (µGy/frame)

Exposure IQ APR 25 frames/s (µGy/frame)

23 0,70 0,026 0,10

Chapter

18 1,06 0,040 0,14

13 1,37 0,058 0,22

Example made for Philips MedicalSystem by RTI, Sweden BasedonprotocolmadebyRolandCarneborn,PMSSweden

PMX-III/PH Manual 1999-03/6.0B 61

Examples of Field Measurements SERVICE / MAINTENANCE

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REMOTE CONTROL USING ORTIGO Introduction

6 REMOTE CONTROL USING

ORTIGO

6.1 Introduction

oRTIgo is a Quality Assurance software package which offers you maximum freedom in managing and documenting X-ray measurements. Using the software is simple, just choose predefined measurement templates or create them to suit your own specifications.

Main Features

Customized measurement records with user selected template structure

•

Fully user designable templates.

•

Automatic calculations: % or

• mGy/mAs, linearity, mean value, and more

• kVp reading are automatically compensated for total filtration

• Dose and dose reading are automatically compensated for the energy response of the dose detector

• Min/Max acceptance limits for all data, with automatic warnings

• Waveform analysis of kVp, radiation output, and dose rate

• Waveform analysis of light and tube current

• User designable print-out formats

•

Can be run from a DOS shell in WINDOWS

•

Export of data

•

Built-in notepad for adding comments to your measurements

•

Text editor

•

Pull-down menus

•

Context-sensitive help texts

•

Hotkeys for easy access to different functions

∆ error, variation of coefficient, reproducibility, HVL,

Chapter

•

DOS file structure for all storage of data

•

Personal password for protection of data and template structure

•

Interface to PMX-III for automatic measurements

PMX-III Manual 1999-03/6.0B 63

oRTIgo version 3.0 REMOTE CONTROL USING ORTIGO

6.2 oRTIgo version 3.0

A new version of the DOS based oRTIgo software was released in November

1998.

Major difference, compared to version 2.20:

Improved user interface, Information about the template settings for detector ,

• detector range, beam quality and PMX-III is now displayed on a “template screen” to assist the user for the measurement.

Improved communication interface with PC

•

Autoread of dose and dose rate values in dosimeter mode

• (Pressing INS stores the value in the active template)

Set dose, set dose rate, % dose and % dose rate (mA, Cd/m²..)

•

The display is continuously updated in multimeter mode during exposure

• (kVp, time, dose, dose-rate (mA, Cd/m²..))

Chapter

• Start up of oRTIgo directly from window explorer by double-clicking the appropriate *.DTA file

• Installation procedure under Windows (W 3.1 / W '95)

• Manual Trig in the waveform analyzer The possibility to manually trig the waveform analyzer is added. This new function is available when measuring the electrometer signal (dose, dose rate, light, mA and mAs) and in combination with MANUAL LOCK mode. There is sometimes a need for the ability to start the sampling manually, for example when measuring a very low signal, using the light detector L100, or when the signal you want to measure need a certain time to stabilize. You can activate this by changing measuring mode in the build mode before entering the waveform analyzer. You can also change measuring mode by pressing "M" after entering the waveform analyzer. You start the sampling by pressing the INS key.

•

Calculation of frames and frames/s or pulses and Hz in the waveform Analyzer The possibility to calculate frames has been changed to give more possibilities when measuring on fluoroscopy and with the light detector L100. It is now possible to use Frame mode to calculate the total number of frames or frame rate frames/s between the two cursors. When enabling frame mode you can now choose between: "ON (Frames)", "ON Frames/s" for dose detectors "ON (Pulses)", "ON (Hz)" for all other detectors and probes. The trig level (Calculation level) can be set between 5 % and 95 %.

•

Possibility to print to COM1, COM2, LPT1, LPT2,and FILE.

•

Bugfix on printout and use of the waveform.

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REMOTE CONTROL USING ORTIGO Connecting PMX-III to a Computer

6.3 Connecting PMX-III to a Computer

Place the PMX-III in the X-ray field for multimeter measurements

•

Connect the interface cable between PMX-III AMP-1 and the computer

• (COM l or COM 2), use serial extension cable if needed.

Connect the ADI-module and detector, use detector extension cable if

• needed.

Power on the PMX-III

•

Start oRTIgo (see next page)

•

Figure 2. Correct connection of the serial cable, the detector cable, and the ADI.

PMX-III Manual 1999-03/6.0B 65

Chapter

Start oRTIgo 3.0 REMOTE CONTROL USING ORTIGO

6.4 Start oRTIgo 3.0

Power on the computer.

•

Place the PMX-III in the X-ray field for multimeter measurements

•

Connect the interface cable between PMX-III AMP-1 and the computer

• (COM l or COM 2), use serial extension cable if needed.

Connect the ADI-module and detector, use detector extension cable if

• needed.

Power on the PMX-III

•

Navigate to the directory where you have stored the oRTlgo software,

• normally “C:\windows\program\ORTIGO30" for windows installation (normally pressing the oRTIgo icon) or ”C:\ortigo30" for dos installation

Start by typing “ORTIGO’ followed by < Enter >.

•

Chapter

• Press < ^L > Move the cursor to a record name, press <Enter> to load it.

The < Fl > key is always available for instant help on current action.

•

Press < Enter > to accept record.

•

Press < Alt M> to activate the Measure menu You can now start to select a measured template from the menu. Follow the instructions on the screen to start to measure.

Please observe that “old” set records with the extension *.set must be renamed to *.std to be able to read in version 3.0

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REMOTE CONTROL USING ORTIGO What is a Record

6.5 What is a Record

The data structure, that oRTIgo uses for data storage, is called a “record”. A record can be divided into the following parts, see figure below:

An oRTIgo record

Template #0

Templates

#1 to #6

Waveform data

Note pad

Template with general information about the measuring conditions.

A template performs a specific measurement. Set values for the X-ray generator and PMX-III and results are stored here. The templates, except for the waveform template, are fully user- design able. A record has six templates and one dedi cated waveform template.

Measured waveforms are stored here. Up to six teen different waveform measurements can be stored in each record.

Text entered in the note pad is stored here.

Chapter

PMX-III Manual 1999-03/6.0B 67

Application example REMOTE CONTROL USING ORTIGO

6.6 Application example

The record file NEWS1 contains templates that show how the new features can be used. The templates are:

Template name Function

I.I test µGy/s 8/A(P2) Shows how the new measuring

text “% unit” has been used to cal culate the accuracy of measured dose rate.

Monitor light level Shows how the light detector L100

and the monitor adapter has been used to measure the light output from a monitor screen.

Chapter

Dose rate, pulsed fluoro Shows how the accuracy of dose

rate has been measured during pulsed fluoro.

Fluoro kV, dose rate, time Shows how the new measuring

mode “Fluoro” is used to measure kVp, time and dose rate during fluoroscopy.

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REMOTE CONTROL USING ORTIGO Application example

PMX-III Manual 1999-03/6.0B 69

Chapter

Application example REMOTE CONTROL USING ORTIGO

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REMOTE CONTROL USING ORTIGO Application example

In the waveform template you find the following waveforms:

Waveform name Function

I.I Pulse simulation Shows a pulse waveform,

25 frames/s

P.fluoro 5 frames/s Shows a pulsed waveform,

5 frames/s

Rad. M.Lock/A.trig Shows kV and radiation output

waveform (manual lock mode)

Rad output, standard Shows kV and radiation output

waveform (standard measuring mode)

Room light, 100 Hz Shows the light output from a light

source. Use part mode (Ctrl-G) when you look at this waveform.

D.rate M.Lock/M.Trig The same as above, but manual

lock mode and manual trig has been used. Use part mode (Ctrl-G) when you look at this waveform.

Monit. Vert.Fr 60 Hz Shows the output from a monitor

with a vertical frequency of 60 Hz.

Test of room strip light Shows the light output from a light

source.

Test of R100 waveform Shows the dose rate waveform

measured with a R100.

Chapter

Test of R100 dose rate Shows the dose rate waveform

measured with a R100.

PMX-III Manual 1999-03/6.0B 71

Application example REMOTE CONTROL USING ORTIGO

P.flu. M.Lock/M.Trig Shows pulsed fluoro, measured

with manual lock mode and man ual trig.

Video monitor 50 Hz Shows measurement of light out

put from a video monitor with a vertical frequency of 50 Hz.

Monitor luminance Same as above.

Monitor cd/m

,70Hz Shows measurement of light out

put from a monitor with a vertical frequency of 70 Hz.

Chapter

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REMOTE CONTROL USING ORTIGO Application example

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Chapter

Application example REMOTE CONTROL USING ORTIGO

Chapter

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REMOTE CONTROL USING ORTIGO Application example

PMX-III Manual 1999-03/6.0B 75

Chapter

List of Hotkeys and Short Cuts REMOTE CONTROL USING ORTIGO

6.7 List of Hotkeys and Short Cuts

6.7.1 General

← , ®

 , ↓

PgUp/PgDn

Home.End

Esc

Enter

Alt D

Alt M

Alt B

Alt X

Move cursor

Within a template: Move the cursor 5 rows up/down

Within a template: Move cursor to top/bottom of template

Within the menu system: Move to previous menu level Within a template: Return to

the menu system

Within the menu system: Select menu item

Pull down the DISK menu

Pull down the MEASURE menu

Pull down the BUILD menu

Pull down the EXPORT menu

Chapter

Alt P

Alt E

Alt O

TAB

F2/Ctrl F2

F3/CtrlF3

F4/Ctrl F4

F5/Ctrl F5

Pull down the PRINT menu

Pull down the EDITOR menu

Pull down the OPTIONS menu

Within the menu system: Return to the template

Within a template: Toggle cursor between measure/set

Help

Activate tempate #0 for text entering/build

Activate template #1 for measure/build

Activate template #2 for measure/build

Activate template #3 for measure/build

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REMOTE CONTROL USING ORTIGO List of Hotkeys and Short Cuts

F6/Ctrl F6

F7/Ctrl F7

F8/Ctrl F8

F9/Ctrl F9

F10

Ctrl A

Ins

Ctrl Z

Activate template #4 for measure/build

Activate template #5 for measure/build

Activate template #6 for measure/buiid

Activate the waveform template for measure/huild

Recalculation (Measuring mode)

Waveform Settings (Building a waveform template)

Adjust parameters

Dosimeter mode: Read a value from the dosimeter

Dosimeter mode: Reset of the dosimeter

Ctrl L

Ctrl S

Ctrl E

Ctrl N

Ctrl R

Ctrl P

Ctrl X

Ctrl QQ

Load a record

Save current record

Activate the text editor

Activate the notepad

Toggle PMX-III ON/OFF line

Print current record

Export current record

Quit oRTlgo

Within a submenu all commands can be accessed by pressing the first letter of the corresponding command.

Chapter

PMX-III Manual 1999-03/6.0B 77

List of Hotkeys and Short Cuts REMOTE CONTROL USING ORTIGO

6.7.2 Waveform Analyzer

F5/Ctrl F5

F10

Show measured waveforms in two separate graphs

Show measured kV waveform

Show radiation output waveform

Dual waveform plot. absolute/relative plot

Show “Waveform Pick List”

If F3 or F4 has been pressed: Calculate between cursors

If F3 or F4 has been pressed: Toggle the active cursor

If F6 has been pressed: Activate multi-plot

If F3 or F4 has been pressed: Print a hard copy

Chapter

Ctrl ¬ ,

Ctrl →

Home/End

PgUp/PgDn

Ctrl G

Ctrl W

Ctrl Z

Ctrl T

Ctrl X

If F3 or F4 has been pressed: Move the cursor fast

If F3 or F4 has been pressed: Move the cursor

to the beginning/end of the waveform

Go to the previous/next part

Go to part number ...

Save the waveform

Dosimeter reset

Toggle between the whole waveform and the active part

Activate SET mode

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REMOTE CONTROL USING ORTIGO List of Hotkeys and Short Cuts

6.7.3 Text Editor and NotePad

¬ , ®

 , ¯

Ctrl ¬ ,

Ctrl →

Home/End

PgUp/PgDn

Ctrl PgUp

Ctrl PgDn

Ctrl y

Ins

Move the cursor

Move the cursor one word

Move the cursor to the beginning/end of the line

Scroll the display one page up/down

Move the cursor to the beginning of the file

Move the cursor to the end of the file

Delete the current line

Toggle insert mode on and off

Shift F3

Mark the beginning of block

Mark the end of block

Delete the marked block

Move the marked block to the current cursor position

Copy the marked block to the current cursor position

Read a file from disk and insert at the current cursor position

Write the marked block to a file

Resize text window (only valid for the notepad)

Chapter

PMX-III Manual 1999-03/6.0B 79

List of Hotkeys and Short Cuts REMOTE CONTROL USING ORTIGO

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DISPLAY CODES, SENSITIVITY AND FILTRATION Display codes

7 DISPLAY CODES, SENSITIVITY

AND FILTRATION

7.1 Display codes

7.1.1 Most Common Display Codes

New Name Description Old Name

Lo.Si

Hi.Si

Sh.E

BAtt

O. FL

OF.Er

Er. 11

X.-Y-

Low signal

High signal

Low kVp

High kVp

Short exposure time

Low battery

Display overflow (electrometer reading > 9999)

Offset error due to negative input signal

Wrong ADI unit (Gy or R) compared to front panel text

Rate indication in the display

ADI defined, for detector X and beam quality Y

Er.1

Er.2

Er.3

Er.4

Er.5

Er.20

Er.2

New

X.-Y-

MAS.X

norM

Ch.Cu

Auto

RA:1

RA:2

RA:3

PMX-III Manual 1999-03/6.0B 81

ADI defined, for MAS-1/MAS-2/MAS-3 probe

Display reading normalised to user factor

Charge/current (only without ADI)

Indicates that electrometer selects range automatically

This is the most sensitive range for low dose rate meas.

Middle dose rate range

High dose rate range (default for use of AMP-1)

PMX-III performs a RESET, wait to exposure until the “c” disappear

MAS.X

norM

Ch.Cu

Auto

RA:1

RA:2

RA:3

Chapter

Display codes DISPLAY CODES, SENSITIVITY AND FILTRATION

7.1.2 Description of the Display Codes

Lo. Si Low signal. The detector signal is too low during the measurement. Increase mA or decrease the distance between PMX-III and the tube. For dental/ fluoro units try to use a time delay using setup tables #9 and #10.

Hi. Si High signal. The kVp detector signal is too high. Decrease mA or increase the distance between PMX-III and the tube; or

The measured range in manual LOCK mode is to low. or

Measured dose is higher than 9999 expressed in the current unit: or

Chapter

The dose rate signal is too high. If the measured dose rate signal is too high you can increase the distance between the detector and the tube. Otherwise you can lower the tube current or deactivate the AMP-1 by selecting a “normal” ADI that does not activate the AMP-1. Using gain 1 or gain 2 instead of gain 3 on PMX-III together with AMP-1 gives a dose rate overflow

Lo Low kVp The measured kVp is lower than the lower limit set by the selected tube/filter combination.

Hi High kVp. The measured kVp is higher than the maximum limit set by the selected tube/filter combination.

Sh.E Short exposure time. The exposure time is too short or the detector detects the start trig but not the time trig. PMX-III cannot calculate a correct kVp value. This measuring situation may occur for a combination of a low X-ray output and low kVp. Try to use longer exposure time and/or increase signal level. For dental/fluoro units try to use a time delay using setup tables #9 and #10.

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DISPLAY CODES, SENSITIVITY AND FILTRATION Display codes

Batt Low battery (Flash in dose rate mode)

Please exchange all batteries for new ones. Also negative current input to the electrometer gives this error.

O.Fl Display overflow (electrometer reading > 9999). oRTIgo can still collect and display the measured values as long as no Hi.Si code appear

Dose rate is greater than 4.6 µGy/s (“8.AP1" ADI) or 46 µGy/s (”8.AP2" ADI) .

OF.Er Offset error due to negative input signal to the electrometer. The reason for this can be that AMP-1 or one of the active mA-probes offset level are outside permitted range.

Er. 6 Time trig error. Random error, make a new exposure. If the error is repeated please make a check of the waveform to confirm that there is no error.

Er. 7 Pulses can not be calculated. The exposure time is too short, PMX-III can not calculate the correct number of pulses.

Note !!

If PMX-III at any time indicates an code 1 to 7 that will not disappear after appropriate changes, it would be advisable to try the following:

•

Use manual LOCK mode to “help” PMX-III to make the correct selection of kV range and gain.

•

Longer delay

•

Longer exposure time

•

Higher mA

This may occur when it is impossible to predict the waveform, for example if the overshoot is much longer than 5 ms. For dental/fluoro units try to use a time delay using setup table #9 (or #11) with a delay of 200 ms or setup table #10 (or #12) with a delay of 2000 ms. You can also try to use long delay times if you know that the X-ray unit has an long start-up sequence (longer than 5 ms), when the output level not is stable.

Chapter

PMX-III Manual 1999-03/6.0B 83

Display codes DISPLAY CODES, SENSITIVITY AND FILTRATION

Er. 8 Not allowed to select LOCK mode until SET exposure done.

Make a new exposure in SET mode before using LOCK mode.

Er. 10 Dose rate error. Dose rate cannot be calculated (only in multimeter mode).

Er.11 Wrong ADI unit (Gy or R) compared to frontpanel text.

Er. 25 Hardware offset level outside permitted range.

The most common reason for this error code is that PMX-III has been exposed to cold or heat, for example during transportation or storage. Please allow PMX-III to return to normal temperature (+20 °C, 68 °F) before it is switched on. A PMX-III heated up to +40 °C (+104 °F) will need at least two hours to return to normal temperature.

Er. 21-23,28,29,31,32 Hardware errors. Please study appendix A in the reference manual for more detailed information of the self test procedure at power on and the meaning of the different error code numbers. Write down the error codes if still present. Please contact your dealer if needed.

Chapter

Er.30 ADI or internal EEprom checksum error

Important calibration data are stored both in the ADI and in an internal EEprom. The PMX-III firmware checks the checksum of this two areas when power on the instrument for safety reasons. See Chapter 10 how to fix this errors yourself with help of the “SAVEEPR5 oRTIgo software. Please contact your nearest dealer or RTI to get help how to fix this error if you don’t can download the backup data into PMX-III.

Er. 50 Serious error Please make sure that you are using the correct sensor area corresponding to the active tube/filter combination and that the X-ray field covers the kVp sensor (RAD or MAM).

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DISPLAY CODES, SENSITIVITY AND FILTRATION KVp Sensitivity Graph

7.2 KVp Sensitivity Graph

Typical sensitivity for PMX-III using CA 1 with a total filtration of 3.0 mm Al at a distance of 50 cm between the tube and the kV detector.

SDD=50 c m

kVp

Typical sensitivity for the PMX-III.

PMX-III Manual 1999-03/6.0B 85

Chapter

Filtration Dependence DISPLAY CODES, SENSITIVITY AND FILTRATION

7.3 Filtration Dependence

The calibration is performed with known parameters such as true kVp, total filtration, and X-ray tube target material. If measurements are made under the same conditions as during the factory calibration, the best accuracy will be achieved. If not, it is necessary to make corrections to the displayed kVp value.

Valid for DC ,HF and 3 phase 12 and 6 pulse units.

100 kV

Chapter

1234567891011

Total Filtration mm Al

Conversion between total filtration and HVL.

90 kV

80 kV

70 kV

60 kV

50 kV

The X-ray tube material and the total filtration must be known to be able to make the correction. To convert from HVL value to total filtration; use the graph in above figure. An HVL value from a half wave rectified unit can be converted to DC-HVL by multiplying it with 1,15.

86 1999-03/6.0B PMX-III Manual

DISPLAY CODES, SENSITIVITY AND FILTRATION Filtration Dependence

The two graphs on next page gives the corrections for different total filtrations.

First graph is valid from 45 to 90 kV and the second graph is valid from 80 to 145 kV. Within the range 80 to 90 kV, it is necessary to use the special display mode that indicates which graph to use

EXAMPLE:

You are measuring on a generator with a total filtration of 4,0 mm Al and you are going to measure at kV settings between 80 and 90 kV.

1. Select setup table #13 to enable the display of filter pair used for kVp measurement, or enable it manually. See section 4.9 and page 4-53 and 4-59 in the reference manual for details.

2. Make an exposure.

3. If measured kVp is between 80 and 90 kVp, information will be displayed to inform which graph to use. The display will show “Fi.1" or ”Fi.2".

Assume the following: Read kVp value in the PMX-III display = 83,5 kVp and “Fi.1”.Known total filtration = 4,0 mm Al.kVp correction from graph #1 = -1,6 kVp.True kVp = 83,5 - 1,6 = 81,9 kVp.

Chapter

PMX-III Manual 1999-03/6.0B 87

KVp Correction Graphs DISPLAY CODES, SENSITIVITY AND FILTRATION

7.4 KVp Correction Graphs

7.4.1 Radiographic - CA-1, 2.0-5.5 mm Al

2,0 mm Al

1,5

2,5 mm Al

0,5

3,0 mm Al

-0,5

-1

3,5 mm Al

-1,5

kVp Correction

-2,5

-2

4,0 mm Al

4,5 mm Al

-3

-3,5

5,0 mm Al

-4

-4,5

5,5 mm Al

45 50 55 60 65 70 75 80 85 90

kVp

kVp corrections for different filtrations in the range 45 - 90 kVp, i.e. for FILTER 1

3,5

2,5

2,0 mmAl

Chapter

1,5

0,5

-0,5

-1,5

-2,5

kVp Correction

-3,5

-4,5

-5,5

-6,5 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155

2,5 mmAl

3,0 mmAl

3,5 mmAl

4,0 mmAl

4,5 mmAl

5,0 mmAl

5,5 mmAl

kVp

kVp corrections for different filtrations in the range 85 - 155 kVp, i.e. for FILTER 2

88 1999-03/6.0B PMX-III Manual

DISPLAY CODES, SENSITIVITY AND FILTRATION KVp Correction Graphs

7.4.2 Radiographic CA-1, 3.0, 4.0, and

5.0 mm Al+0.1 mm Cu

kV correction for 3,0 mm Al + 0,1 mm Cu filtration

kVcorr(F1) = 0.0007(kVmeas)2- 0.1935(kVmeas) + 6.6705

-1

kVcorr(F2) = -0.0004(kVmeas)2+ 0.0405(kVmeas) - 2.7192

-2

-3

-4

kV-corrected

-5

-6

-7

-8 50 60 70 80 90 100 110 120 130

Filter 1 Filter 2

kV-measured

kV correction for 4,0 mm Al + 0,1 mm Cu filtration

kVcorr(F1) = 0.0004(kVmeas)2- 0.1642(kVmeas) + 5.7781

-1

-2

-3

kVcorr(F2) = -0.0005(kVmeas)2+ 0.039(kVmeas) - 2.4483

Filter 1 Filter 2

-4

kV-correction

-5

-6

-7

-8 50 60 70 80 90 100 110 120 130

kV-measured

PMX-III Manual 1999-03/6.0B 89

Chapter

KVp Correction Graphs DISPLAY CODES, SENSITIVITY AND FILTRATION

-1

-2

-3

-4

kV-correction

-5

-6

-7

-8 50 60 70 80 90 100 110 120 130

kV correction for 5,0 mm Al + 0,1 mm Cu filtration

kVcorr(F1) = 0.0002(kVmeas)2- 0.1651(kVmeas) + 5.9913

kVcorr (F2) = -0.0005(kVmeas)2+ 0.0288(kVmeas) - 1.7892

Filter 1 Filter 2

kV-measured

Chapter

EXAMPLE:

Read kVp value on the PMX-III display = 100.0 kV

Read filter pair on the PMX-III display = Fi:2

Known total filtration=4mmAl+0,1mmCu

kVp correction from the graph or from the equation above = -3.5 kV

True kVp value = 100.0 - 3.5 = 96.5 kV

Please note that the absolute accuracy for each instrument is stated in the kVp calibration record. The inaccuracy of the correction graph information is less than ±3 %.

90 1999-03/6.0B PMX-III Manual

PRECAUTIONS AND MAINTENANCE Precautions

8 PRECAUTIONS AND

MAINTENANCE

8.1 Safety Rules

The PMX-III family of kVp meters is intended for service and quality control of

• diagnostic X-ray equipment. It is not intended for use during or together with diagnostic examinations of patients.

RTI Electronics AB takes no responsibility for misuse of any instrument of the

• PMX-III family or use together with instruments that the PMX-III family is not intended for.

RTI Electronics AB assumes no responsibility to customers not following these

• safety precautions.

Only authorized personnel are permitted to open the instrument.

•

8.2 Precautions

• Do NOT exceed the DC input limits specified (max. 15 V).

• Remember to make all connections when the power is off.

• Do NOT expose the instrument to direct sunlight, extremes of temperature and humidity, or dew fall.

• Do NOT input any voltage signal to the electrometer terminals.

• Do NOT use the AMP-1 with a current source higher than 1 µA.

• Be carefully NOT to hold the PMX-III only by the AMP-1 itself. You may break the back panel or connectors on the PMX-III/AMP-1.

•

Do NOT use the AMP-1 and the AMP-1 ADI without using the existing two knobs to fasten the parts together.

•

Do NOT make battery replacement or change BRB-1 with the power switch set to ON position.

•

Do NOT use the old external serial interface cable with two 9 pin connectors.

•

Do NOT select gain 1 or 2 on the PMX-III electrometer when AMP-1 ADI’s is used. AMP-1 only uses gain 3 on the PMX-III electrometer.

•

Avoid to expose the AMP-1 to high dose rates. Especially when the P1 or P2 ADIs is used. Put only the detector in the field in in this case to minimize the risk of self ionisation inside the AMP-1 that may effect the very sensitive electrometer. When normal ADIs are used the AMP-1 electrometer is not activated and therefore the above situation is not relevant.

Chapter

•

Carefully insert power detector plug into PMX meter to avoid damage of measuring pin, also, when removing, do not pull the cable but move the plug housing backwards.

PMX-III Manual 1999-03/6.0B 91

Maintenance PRECAUTIONS AND MAINTENANCE

Do NOT try to adjust the offset level on the AMP-1. This should only be done by authorised service personnel.

8.3 Maintenance

Remember to take out the batteries, to avoid leakage, if the instrument is not to be

• used for a longer period of time.

Do not use aromatic hydrocarbons or chlorinated solvents for cleaning. Clean the top panel and front panel with a mild solution of detergent and water.

Chapter

92 1999-03/6.0B PMX-III Manual

Notes and Reports Application Notes Related to PMX-III

9 Notes and Reports

9.1 Application Notes Related to PMX-III

Name and Issue Date Description Included

5-AN-52003-19 September 1998

5-AN-52003-18 September 1998

03-017/01 December, 1996

03-016/01 October, 1996

03-015/01 September, 1996

03-014/01 September, 1996

Shortform Detector Selection Guide Yes

Dosimeter Ranges for PMX-III Used with the Dose Detectors R25 and R100

Typical energy correction for R25 and R100 when measuring with Cu filtration

Extended graph for HVL-Total filtration conversion

Maximum mA Settings at Different kVp When Using the R25 or R100 Dose Detector with PMX-III

Measurements of luminance using the L100/M light Detector

Yes

03-011/01 November,1994

03-010/01 September, 1994

03-009/01 March, 1994 HVL measurements using the PMX-III kit

03-006/01 March, 1993

Quality control of automatic exposure control (AEC) system

Energy corrections factors for the R100 solid state detector

HVL-total filtration conversion in oRTIgo PMX

For a complete list of application notes, visit our web page www.rti-e.se.

Please observe that useful detector information also is include in the red calibration record envelope that is delivered with each PMX-III.

PMX-III Manual 1999-03/6.0B 93

Chapter

1R $1

Standard calibrations and measuring ranges with PMX-III

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Type ADI

code

R25 7/A 50-150 kV, W/23 mm Al

R25 7/AP1 50-150 kV, W/23 mm Al Image I. dose rate input 0,120-18,4 µGy/s 13,7-2100 µR/s R25 7/AP2 50-150 kV, W/23 mm Al Image I. dose rate input 0,40-185 µGy/s 46-21000AµR/s R25 7/B 50-150 kV, W/3 mm Al Skin dose & dose rate 0,004-185 mGy/s

R25 7/D 25-35 kV, Mo/30 µm Mo Skin dose & dose rate

R100 8/A 50-150 kV, W/23 mm Al Film dose & dose rate 1,0-46000AµGy/s

R100 8/AP1 50-150 kV, W/23 mm Al Image I. dose rate input 0,030-4,6 µGy/s 3,3-525 µR/s R100 8/AP2 50-150 kV, W/23 mm Al Image I. dose rate input 0,10-46 µGy/s 11-5250 µR/s R100 8/B 50-150 kV, W/3 mm Al Skin dose & dose rate 0,001-46 mGy/s

R100 8/D 25-35 kV, Mo/30 µm Mo Skin dose & dose rate

L100 6/U

L100 6/Y Illuminance, diffuser Ambient light levels 0,25-4000 lx

MAS-1 5 Invasive mA and mAs mA and mAs 0,10-2000 mA

MAS-2 4 non-invasive mA & mAs mA and mAs 50-2000 mA MAS-3 J non-invasive mA & mAs mA and mAs 0,10-2000 mA

Beam Quality Typical use

Film dose & dose rate 4,0-185000AµGy/s

(breast)

Luminance, MON adapter Film viewing box

CRT

Typical rate range with PMX-III

r1: 4,0-1850 r2: 250-18500 r3: 2000-185000

r1: 0,004-1,85 r2: 0,25-18,5 r3: 2,0-185 0,008-370 mGy/s r1: 0,008-3,7 r2: 0,5-37 r3: 4,0-370

r1: 1,0-460 r2: 60-4600 r3: 500-46000

r1: 0,001-0,46 r2: 0,06-4,6 r3: 0,5-46 0,002-92 mGy/s r1: 0,002-0,92 r2: 0,12-9,2 r3: 1,0-92

0,5-23000Acd/m r1: 0,5-230 r2: 30-2300 r3: 250-23000

0,05-1000 cd/m

r1: 0,25-40 r2: 5-400 r3: 45-4000

r1: 0,1-20 r2: 3-200 r3: 25-2000

0,027-1260 R/min r1: 0,027-12,6 r2: 1,64-126 r3: 13,7-1260

0,027-1260 R/min r1: 0,027-12,6 r2: 1,64-126 r3: 13,7-1260 0,055-2520 R/min r1: 0,055--25 r2: 3,3-252 r3: 27,4-2520 0,007-315 R/min r1: 0,007-3,15 r2: 0,41-31,5 r3: 3,4-315

0,007-315 R/min r1: 0,007-3,15 r2: 0,41-31,5 r3: 3,4-315 0,014-630 R/min r1: 0,014-6,3 r2: 0,82-63 r3: 6,85-630

Chapter

Special mammographic calibrations

R25 7/(E) 22-40 kV, Mo/25 µm Rh Skin dose & dose rate Same as for 7/D R25 7/(F) 25-46 kV, Rh/25µm Rh Skin dose & dose rate Same as for 7/D R25

R25 7/(J) 23-35 kV, W/50 µm Rh Skin dose & dose rate Same as for 7/D R100 8/(E) 22-40 kV, Mo/25 µm Rh Skin dose & dose rate Same as for 7/D R100 8/(F) 25-46 kV, Rh/25µm Rh Skin dose & dose rate Same as for 7/D R100 8/(I) 25-40 kV, Rh/1,0 mm Al Skin dose & dose rate Same as for 7/D R100 8/(J) 23-35 kV, W/50 µm Rh Skin dose & dose rate Same as for 7/D

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94 1999-03/6.0B PMX-III Manual

7/(I) 25-40 kV, Rh/1,0 mm Al Skin dose & dose rate Same as for 7/D

Note that the PMX-III display can no

When measuring on CRTs, the measuring range depends on the frequency and the after glowing time in the phosphors.

The table shows a typical range.

t show higher values than 9999. With oRTIgo also higher rate values can be shown.

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The dose detectors R25 and R100 used with the PMX-III electrometer

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PMX-III with oRTIgo

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PMX-III Manual 1999-03/6.0B 95

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Chapter

1R 

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Typical Energy

R100

Correction

kV Cq

50 0,929 55 0,956 60 0,977 65 0,991 70 1,00 75 1,005 80 1,007 85 1,007

90 1,005

95 1,002

100 0,999 65 1,006 105 0,996 70 1,010 110 0,993 75 1,011 115 0,991 80 1,008

120 0,990 85 1,006

125 0,990

130 0,991 65 1,013 135 0,992 70 1,015 140 0,994 75 1,011

145 0,997 80 1,004 150 0,999 85 1,001

Application:

kV range: 50-150 kV Reference point: 70 kV Anode: W Filtration: 3 mm Al + 20 mm Al

3mmAl+1,5mmCu

3mmAl+2,0mmCu

8/A

Image Intensifier and Low Dose/Rate Measurements

3 mm Al + 1,5 and 2,0 mm Cu

Example:

Measured or set kVp = 60 kV

Measured dose = 0,50 mGy

Correction factor Cq = 0,977 for 60 kV Corrected dose = 0,977 x 0,50 = 0,49 mGy

Inaccuracy:

The inaccuracy of the typical correction

factor is less than ±4 %.

Note:

Check your manual to verify when you have to do the correction manually.

-8,92E-02 4,04E-02 3,07E-06 -6,323E-09

1,04

1,00

0,96

0,92

50 60 70 80 90 100 110 120 130 140 150

Typical Correction Graph

3mmAl+2,0mmCu 3mmAl+1,5mmCu 3mmAl+20mmAl

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57, (OHFWURQLFV $% 3DJH 

96 1999-03/6.0B PMX-III Manual

RTI PMX-III X-Ray User manual

Specifications and Main Features

Frequently Asked Questions

User Manual

TABLE OF CONTENTS

PMX-III Manual 1999-03/6.0B 7