PTW DIAMENTOR E Instruction Manual

Instruction manual

DIAMENTOR E

[D151.131.0/2]

(01/98) Ra/ri (15113100.Gbe)

* PTW-Freiburg
Loerracher Straße 7
D-79115 Freiburg

(

FAX
E-Mail

([phone]
([phone]
[e-mail]

Registergericht Freiburg
HRB NR. 1673

Geschäftsführer:
Dr. Edmund Schüle,
Dr. Christian Pychlau

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

Security Information

- 2 - Security Information

• The instruction manual is an integral part of the
device. It should always be kept near the device.
Observance of the manual is a prerequisite for
proper device performance and correct
operation.

• Operator safety, specified measuring accuracy
and interference-free operation can be
guaranteed only if original devices and parts are
used. Furthermore only the accessories listed in
this manual are approved by PTW-Freiburg and
may be used in conjunction with the device, or
else accessories whose use has been expressly
permitted by PTW-Freiburg. Safe operation and
proper device performance are not guaranteed if
accessories or consumables from other
manufacturers are used.

• PTW-Freiburg cannot be held liable for damages
resulting from the use of accessories or
consumables from other manufacturers.

• The warranty period is 1 (one) year and begins
on the day of delivery.
It is unaffected by repairs covered by the
warranty regulations.

• Devices on which moisture has developed as a
result of temperature changes may not be
switched on unless completely dry.'

• PTW- Freiburg considers itself responsible for
safety, reliability and performance of the device
only, if assembly, extension, readjustment,
modifi-cation or repair is carried out by PTW­Freiburg or by persons authorized by PTW­Freiburg,and if the device is used in compliance
with the technical documentation.

• This technical documentation is in conformity
with the device specifications and all applicable
safety standards valid at printing date. All
rights are reserved for devices, circuits,
techniques and names appearing in the manual.

• No part of the technical documentation may be
reproduced without written permission from
PTW-Freiburg.

CE-Marking

• The product bears the CE-mark "CE-0124" in
accordance with the Council Directive
93/42/EEC about Medical Devices and fulfills
the essential requirements of Annex 1 of this
directive. The product is a class IIb device
(MDD).

Electromagnetic immunity

• The product fully complies with the
electromagnetic immunity requirements of
standard EN 60601-1-2 `Electromagnetic
Compatibility - Medical Electrical Equipment`.

Safety Instructions

• Dispose the packaging material according the
applicable waste disposal regulations and keep it
out of children's reach.

• The product is a medical device. Only person
with sufficient knowledge and skill may use the
device.

• Before using the device, the operator must
ascertain that it is in correct working order and
operating condition.

• The operator must be trained in the use of the de-
vice.

• Set up the device so that the operator has a clear
and unobstructed view of the control panel.

• The product is not suitable for operation in
areas of risk where an explosion hazard may
occur. Explosion hazards may be caused by the
use of combustible anesthetics, skin-cleansing
agents and disinfectants. Furthermore the
device is of restricted suitability for application
in oxygen-enriched atmospheres. The
atmosphere is considered to be oxygenenriched
when more than 25% of oxygen or nitrous oxide
is added to the ambient air.

• Set up the device in a location which affords
sufficient ventilation. The air gaps of the device
must not be obstructed. Always observe the
ambient conditions as indicated in the `Technical
Specifications`.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

Operation in the patient environment

• The product represents a medical system. The
product may be operated in the patient
environment.

Exclusion of operation as device with patient
contact

• Neither the device nor any peripheral device may
have contact to the patient.

Exclusion of operation as controlling instrument

The device is only for use to measure the dose
within radiation field. The product must not be used
to control radiodiagnostic equipments.

Safety Instruction to avoid electrical hazard

• The product is a device of IEC 601 protection
class II.

• Before connecting the device to the power line,
make sure that line voltage and frequency are
equivalent to the ratings indicated on the
nameplate of the device.

• Before putting the device into operation, visually
inspect all connection cables for signs of
damage. Damaged cables and connectors must
be replaced immediately.

- 3 - Security Information

Never touch the patient and open connectors of the
device at the same time.

Please observe the manual !

PTW-Freiburg
Physikalisch Technische Werkstätten
Dr. Pychlau GmbH
Lörracher Str. 7
79115 Freiburg
GERMANY
Phone: ++49-761-49055-0
Fax: ++49-761-49055-70

E-Mail: [e-mail]

This symbol stands for:

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

1 Introduction .............................................................................................................................5

2 Connecting the DIAMENTOR E to the Mains .....................................................................6

3 Description of the DIAMENTOR E.......................................................................................7

4 Description and Mounting of the Ionization Chamber........................................................8

5 Connection and Care of the Ionization Chamber.................................................................9

- 4 - Contents

Contents

Page:

6 Adjusting the DIAMENTOR E ............................................................................................ 10

6.1 Adjustment during the Installation ....................................................................................... 10

6.2 Checking the Calibration after Installation........................................................................... 10

7 Checking the Stability ........................................................................................................... 12

8 Further Information..............................................................................................................13

8.1 Influence of Air Temperature and Humidity ........................................................................13

8.2 Checking the Leakage...........................................................................................................13

8.3 Influence of Field Size and Dose Rate..................................................................................13

8.4 Wall mounting ......................................................................................................................14

9 Time Schedule for regular Checks.......................................................................................15

10 Technical Data .....................................................................................................................16

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 5 - Introduction

1 Introduction

It is a well recognized goal to keep the patient's load during diagnostic X-ray examinations as
low as possible. Besides the possibilities to adjust the voltage, the current and the filtration (i.e.
the doserate), adjustable quantities during the examinations are the beam area and the
irradiation time. The task of the diagnostic dosemeter DIAMENTOR E is to measure the
product of dose rate, exposure time and area in cGycm². This product is a measure for the
patient's load.

The German regulation ("Röntgenverordnung") suggests to measure and to record the dose area
product. The DIAMENTOR E simplifies these recordings considerably.

The instrument consists of ionization chamber, electrometer with built-in display, connection
cable and separate power supply.

The area of the ionization chamber must always be bigger than the cross section of the beam.
The ionization chamber automatically determines the product of the different field sizes and the
dose, i.e. the dose area product. The patient's load is recorded during fluoroscopy as well as
during radiography. Nonstop alternating operation between fluoroscopy and radiography is
possible.

The device is calibrated in such a way that one step of the counter is equivalent to 1 cGycm².

The DIAMENTOR E complies with the rules laid down in the German regulation DIN 6819.

The working principle of the DIAMENTOR E is based on the fact that X-rays inside the
special DIAMENTOR ionization chamber produce a well defined amount of charge during the
time of exposure. This amount of charge is proportional to the product of dose and beam area
and is shown on a LC display with 4 1/2 digits.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 6 - Connecting the DIAMENTOR E to the Mains

2 Connecting the DIAMENTOR E to the Mains

The DIAMENTOR E gets its power via an external power supply with + 15 V DC (see
picture 1). For a mains voltage of 115 V AC it is recommended that the PTW power supply
T99021 or T99008 is used. For a mains voltage of 230 V AC, it is recommended that the PTW
power supply T99009 or T99008 is used.

If the power outlet is different from the mains connector of the power supply, please use an
appropriate adapter.

The DIAMENTOR E with the accompanying power supply is a class II instrument. The unit is
intended for continuous operation.

Picture 1: Power Cable

Picture 2: DIAMENTOR E, general view

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 7 - Description of the DIAMENTOR E

3 Description of the DIAMENTOR E

Picture 3: DIAMENTOR E, connectors

1. Socket for chamber cable

2. Socket for power cable

3. Test button

4. On/Off switch

5. Calibration potentiometer

The calibration potentiometer allows to adjust the response of the DIAMENTOR E in
accordance with the ionization chamber in use. See also chapter 6.2.

If the test button (picture 3, 3) is pressed, a charged capacitor is connected to the amplifier in­put. This results in a well defined number of counts. The status of the counter after this proce­dure allows to estimate the response of the amplifier and makes an adaptation of the used
chamber possible. A detailed description of this subject is given in chapters 6 and 7 of this
manual.

If the high voltage is not sufficient or missing at all, the DIAMENTOR E shows a colon
between the second and third and between the third and fourth digit of the display. This also
happens immediately after switching on the DIAMENTOR E until the high voltage has reached
its final value.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 8 - Description and Mounting of the Ionization
Chamber

4 Description and Mounting of the Ionization Chamber

The standard ionization chamber type B (no 57523) has the outer dimensions 17 cm x 18.5 cm
x 1.7 cm for a maximum diaphragm opening of 14.5 cm x 14.5 cm.

On special request the chamber type A (no 5754) can be supplied. This chamber has the outer
dimensions 21 cm x 18.5 cm x 1.7 cm for a maximum diaphragm opening of 18 cm x 18 cm.

Guide rails of the appropriate size are fitted to the ionization chamber to enable the user to slide
the chamber into the guides found a most light beam diaphragms. Both types of chambers are
70 % transparent to visible light and do not impair the use of the light beam diaphragm. The
ionization chambers present an additional beam filtration of approximately 0.2 mm Al
equivalent according to DIN 6863 part 2. Further information about the ionization chambers
can be extracted from the data sheets.

The ionization chamber is connected to the DIAMENTOR E via cable type K3S. This cable
has an inner conductor which is connected to the collecting electrode, a first inner shield
connected to the guard potential, a second little shield connected to the polarizing voltage of +
500 V and a third outer shield connected to earth. The plugs and sockets of the cable are also
connected to the outer shield (earth).

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 9 - Connection and Care of the Ionization
Chamber

5 Connection and Care of the Ionization Chamber

The connection between the ionization chamber and the DIAMENTOR E is performed by the
cable T26004. This is a special cable with cable core and three concentric shieldings. The metal
parts of plug and socket are connected to the outer shielding which has mass potential. When
installing the cable, it must be sure that plug and socket of the cable do not touch metallic parts
of the X-ray machine, to avoid current loops.

Do not clean the surfaces of the ionization chambers with alcohol or other solvent materials.
Use only a moistened cloth or a tissue with one of the following disinfectants:

1. 2% Lysoform

2. 2% Korsolin

3. 1% watery solution of Sokrena

4. 5 % Sagrotan
5 5 % Gigasept

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 10 - Adjusting the DIAMENTOR E

6 Adjusting the DIAMENTOR E

6.1 Adjustment during the Installation

The DIAMENTOR E is calibrated in the factory. During this calibration the ionization chamber
gets a chamber factor KG. The DIAMENTOR E itself gets a characteristic factor QT. The
product of these two factors gives the check reading nc:

nc = QT ⋅ K

This check reading nc must be adjusted by using the calibration potentiometer (see picture 3,

5).

The procedure should be performed as follows:

Connect the chamber to the DIAMENTOR E. Press the test button for approximately 1 s, then
release it and read the value on the display. If this displayed value differs from the calculated
nc, the calibration potentiometer must be adjusted. Repeat this procedure until the correct value
of nc is displayed. The RESET button must be pressed before each test.

G.

(1)

6.2 Checking the Calibration after Installation

During the factory calibration the chamber factor kG is measured with an absorber of 0.35 mm
Al equivalent between the ionization chamber and the X-ray focus. This absorber simulates a
mean value between undercouch and overcouch X-ray tube installations.

If the DIAMENTOR E is used on an overcouch tube (with no additional absorption between
chamber and patient), the factory calibration causes a reading that is approximately 9 % too
low. When the ionization chamber is used on an undercouch X-ray tube (where there is
approxi-mately 0.5 mm - 0.7 mm Al equivalent between chamber and patient), the reading of
the DIAMENTOR E is approximately 3 % too high.

A precise check of the calibration after installation is only possible by comparison with a
reference dosemeter. This check should be done annually.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

Calibration procedure:

a) The couch should be positioned horizontally.
b) The diaphragm should be adjusted to give a field size of 10 cm x 10 cm (this can be

measured accurately by exposing a film in this plane).

c) The distance between focus and the measurement plane should be noted (this distance

should be around 100 cm).
d) A reference dosemeter should be placed in the reference plane.
e) A comparison of the dose area product as indicated by the DIAMENTOR E with that

calculated from the reference dosemeter (dose times area) should then be made at a

range of set kVp values across the normal operating range of the X-ray unit. The com-

parison at a range of field sizes (with fixed kVp and mAs) may also be performed.
f) The mean values of these comparisons will enable the user to derive a suitable

calibration factor or to adjust the sensitivity of the meter, so that the indicated and

measured values match. This calibration should be performed at the typically used

doserates.

- 11 - Adjusting the DIAMENTOR E

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 12 - Checking the Stability

7 Checking the Stability

The stability of the calibration can be checked with the test button (picture 3, 3) as follows:

Press the test button for approximately 1 second and then release it. By doing so, an amount of
charge is fed into the amplifier. This amount of charge is constant within ± 1 %. If the
sensitivity of the DIAMENTOR E has not changed, the check reading nc must also be constant.

If it is not (i.e. the check reading deviates by more than ± 5 % from that check reading calcu­lated with the values in the test certificate), a calibration according to chapter 6 should be per­formed.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 13 - Further Information

8 Further Information

8.1 Influence of Air Temperature and Humidity

As long as the DIAMENTOR E is used in the range + 10 °C to + 40 °C, the response changes
by less than ± 5 %.

If the DIAMENTOR E is used in environments with high humidity (for example 30 °C, 75 %
relative humidity), a film of moisture might cover parts of the instrument or chamber and can
cause an increase of the leakage current (see chapter 8.2).

If such a leakage current is observed, the DIAMENTOR E should be placed for about 24 hours
in dry warm air with a maximum temperature of 50 °C. It is advisable to carry out such a
drying procedure after each transport over longer distances.

8.2 Checking the Leakage

The reading of the DIAMENTOR E may be affected by leakage current. If a not irradiated
ionization chamber causes a reading on the display, leakage current most probably is the
reason.

A check for leakage is carried out (preferably over night) by leaving the instrument switched on
and having the chamber connected but not irradiated. Not more that one digit per hour should
appear (see also chapter 9).

8.3 Influence of Field Size and Dose Rate

The smallest current is delivered to the DIAMENTOR E when the chamber is used with the
smallest field size and the lowest exposure rate.

The greatest current is delivered to the DIAMENTOR E when the chamber is irradiated with
the largest field size and the highest exposure rate. In the range from 100 cGycm²/h to 30,000
cGycm²/s, the response changes by less than ± 5 %.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 14 - Further Information

8.4 Wall mounting

If required, the DIAMENTOR E can be attached to the wall in an easy way. Just screw the
delivered screws into the wall and make sure that they have a perpendicular distance of 140
mm. Please make sure that the maximum distance between the wall and the head of the screw
is 6 mm. Now you can slide the DIAMENTOR E over the screws through the holes in the rear
of the instrument. The DIAMENTOR E is finally fixed by now sliding it a little bit downwards.

Instruction Manual
DIAMENTOR E
[D151.131.0/3]

- 15 - Time Schedule for regular Checks

9 Time Schedule for regular Checks

The proper function of the DIAMENTOR E can be checked with the help of the test button
(picture 3, 3) and by a calibration according to chapter 6 of this instruction manual.

It is recommended to perform the check with the test button regularly (especially if there are
hints concerning changed or irregular measuring results). It is also recommended to perform the
calibration according to chapter 7 every second year.

If leakage occurs that can not be fixed by the drying procedure described in chapter 8.1, a check
of the DIAMENTOR E, chamber cable and chamber should be performed:
First check the leakage with the DIAMENTOR E alone, i.e. without a cable or a chamber con­nected. If then the results are normal, the problem most probably is either in the cable or in the
chamber. If the results are not normal, then most probably there is a problem with the electron­ics of the DIAMENTOR E. In that case the DIAMENTOR E must be send back to PTW­Freiburg or to an authorized technician.

W a r n i n g !

The DIAMENTOR E should only be repaired by PTW-Freiburg or by authorized

service personnel.

Instruction Manual

±

- 16 - Technical Data
DIAMENTOR E
[D151.131.0/3]

10 Technical Data

Device designation and use: DIAMENTOR E type 11002 dose area product meter

according to IEC 580 for measurements in diagnostic
radiology

Manufacturer: PTW-Freiburg

Mode of operation: Continuous operation

Electrical Resolution: (0.4 ... 1.4) nC/digit

Radiological Resolution: 1 cGycm²

Maximum counting rate: 30 kHz

Range of dose area product rate: max. 30.000 cGycm²/s

min. 0.03 cGycm²/s

Display: LCD with 4 1/2 digits

Warm-up time: 10 min

Response time: 1 s

Overall uncertainly of the measuring

±

25 %

system according to DIN 6819
Accuracy of the display:

3 % ± 1 digit

Mains: 115 V / 230 V AC + 10 % / - 15 %

±

50 ... 60 Hz

3 Hz, with separate power supply

Power supply 15V DC; 300 mA

External power supply - PTW T 99021

PTW T 99009 (recommended for use with 230 AC) Euro Plug

-

PTW T99008 (recommended for use from 85 V ... 264 V AC

-

(recommended for use with 115 AC) US Plug

wide input range)

Classification according to IEC601-1 Class II

Normal Conditions
Temperature:
Humidity:

10 0C ... 40 0C
10 % ... 75 % rel. humidity, max. 20 g/m³

Dimensions: 13.7 cm x 19.0 cm x 4.4 cm (LxWxD)

Weights: electrometer 516 g

power supply T99021 and T99009 525 g
power supply T99008 370 g

Chamber voltage 475 V

Chamber connector: Type V

Instruction Manual

- 17 - Technical Data
DIAMENTOR E
[D151.131.0/3]

Chamber: PTW type B, type no. 57523

Filtration of the chamber: equivalent to 0.2 mm Al

Transparency of the chamber: > 70 %

n