g
DOC. ID: DXSE0012
MANUFACTURING PROCEDURES
GE Medical Systems
TITLE: DEXA PM Work Instructions
LUNAR
REVISION: G
DATE: 2/28/02
WRITTEN BY: Jeff Franz
APPROVED ON CO: L10173
PURPOSE
This procedure describes the steps necessary to do a Planned Maintenance Check on
a DEXA scanning system at a customer's site, and to assure that the system is
operating within GE-LUNAR's specifications and in compliance with applicable Federal
and State regulations.
APPLICATION
This procedure applies to all employees performing Planned Maintenance or Site
Certification of DPX Series or PRODIGY, and DPX-NT scanning systems.
SAFETY PRECAUTIONS
When power is applied this equipment generates ionizing radiation. Take precautions
that no part of your body passes through the x-ray beam when the equipment is
energized.
ASSOCIATED MATERIALS
DXAP0008 DPX-Series Installation Test Procedures
DXAP2007 Prodigy Hacksaw Test
DXAP3002 DPX-NT Installation Test Procedures
DXQC0022 Aluminum Spine Phantom Scan Procedure
DXQC2022 enCORE software Aluminum Spine Phantom Scan Procedure
DXSE0036 OINK Daughter board and Limit Switch Field Replacement Instructions
DXSE0038 DEXA PM Quality record
DEFINITIONS
DPX Series scanners are all non- Prodigy, non- DPX-NT/MD+ scanners.
enCORE based systems are all PRODIGY and DPX-NT/MD+ scanners.
PRODIGY I systems are defined as PRODIGY systems with system numbers 11999
and lower.
DPX-NT (A) systems are defined as DPX NT systems with system numbers 71999 and
lower.
QUALITY SYSTEM DOCUMENT Page 1 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
REV: G DATE: 2/28/02 CO: L10173
PROCEDURE
A. QA HISTORY AND ERRORLOG.
1. Perform a Quality Assurance test to insure the system is operating.
a. Verify that all tests on the QA are passing.
2. DPX Series scanners:
The QA values needed may be found by viewing the QA database (F4
Database options – F2 QA History) and / or in the Daily QA printouts in the
Customer’s QA binder.
a. Verify that the Detector has not lost significant resolution by checking that
the high and low energy air counts have not decreased by more than 10%
from the date of installation or the date of the last tube head or detector
change).
b. Verify that the air ratio has not changed by more than .02. from the date of
installation or last tube head or detector change (calculate from earliest
QA or lookup on QA printouts).
3. Systems with enCORE software
a. Copy the QA.mdb file to a diskette (Tools / Send Configuration / Select
Error Log and QA Database, make sure compress Files is selected and
select Span Multiple Disks if necessary).
b. Select the appropriate drive (3 ½ floppy A: ) insert disk into drive and click
OK.
c. Label with system number and PM, the file may be mailed to Service
Engineering or email file to lunar.support@med.ge.com
NOTE: This is only to gather statistical in formation on enCORE ba sed
systems performance, there will be no follow up regarding these QA histories.
4. Analysis of the QA History file
a. DPX Series
i. Verify % Spillover is between 6.3 and 9.5
ii. Check the Air Ratio – it cannot deviate more than .02 since the last
detector / tube change
iii. Check the low air counts – a change greater than 10% since the
date of last detector change indicates a failing detector
iv. Check the Large standard Mass – should not deviate more than
2%
QUALITY SYSTEM DOCUMENT Page 2 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
v. If any of the above parameters are failing, call GE-Lunar Customer
Support for help diagnosing the system.
1. To aid in diagnosis, email the QA.MDB file to
lunar.sppport@med.ge.com
5. Review the error log(s).
b. DPX Series systems print from DOS prompt
i. C:\> ERRDUMP –L –N >PRN
1. See DPX Series CSB Vol 9 for DPX Series Error Log
Interpretation
c. enCORE based systems Tools\ Error Log – add to instructions
d. Verify that there are no hardware subsystem failures (X-ray, Detector,
Mechanical)
e. Contact Lunar Service Department if any unexplained or unusual errors
are discovered in the error log.
i. Error Log may be faxed to 608-826-7107 to aid in interpretation.
REV: G DATE: 2/28/02 CO: L10173
f. Delete error log for DPX Series (C:\LUNAR> del err_320.bin or C:\LUNAR
del errlog.bin).
g. Start a new error log for enCORE-based systems by clicking on Initialize
Log.
B. HOST PC MAINTENANCE
1. Clean the Printer according to the manufacturer’s instructions
a. For Hewlett Packard Printers go to www.hp.com and search the support
pages for the customer’s printer model.
2. DPX series systems:
a. From a DOS prompt
i. Delete contents of C:\SCRATCH and C:\PRNTMNGR directories.
ii. Delete all *.CHK files in C:\ directory.
3. Software updates
a. DPX Series systems: all DPX-IQ densitometers may be updated to
version 4.7e software free of charge.
b. All other (non-IQ) DPX Series Densitometers should be running version
3.65 or 4.7e (if upgraded to IQ software)
c. If the customer is running a version lower than 4.7e, or 3.65 ask them if
they are interested in this free update, they may get by contacting the GELunar Apps line (USA) or you may order it from GE-Lunar at
lunar.support@med.ge.com
or at 866-225-4771.
QUALITY SYSTEM DOCUMENT Page 3 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
d. enCORE based systems:
i. Contract and W a rranty customers are entitled to free software
updates (all software versions <6.0 are updates, > 6.0 is
considered an upgrade and all customers must purchase it)
ii. Billable customers may purchase software updates by contacting
GE-Lunar at 866-225-4771.
C. SCAN TABLE MAINTENANCE
1. Remove the scanner tabletop.
a. Power down the scan table.
b. DPX Series tables – unlock the end panel doors and remove the tabletop
screws.
i. DPX-IQ
ii. Non DPX-IQ
c. DPX-NT – unlock the end panels and remove the tabletop screws.
REV: G DATE: 2/28/02 CO: L10173
i.
d. PRODIGY – lift up the table pad and remove the 4 counter sunk 1/8” hex
head screws in the 4 corners of the tabletop.
2. Clean the scanner interior
a. Clean the electronics pan of dust and dirt.
b. Wipe the dust and dirt off of the rear longitudinal rail and the transverse
rail.
3. Inspect mechanical parts and cables for wear and breakage.
a. Check all cables on the cable trough for wear
b. Check the v-wheels on the rear longitudinal carriage for appropriate
tension Insert V-wheel instructions.
4. X-Ray Generator
a. Power up the scan table.
b. Ramp the scanner to the appropriate kV / mA and read the test points on
the appropriate board as indicated in the X-Ray Settings table on
DXSE0038.
i. DPX Series
1. Load the version specific diagnostic software from the Tools
disk – from a DOS prompt type: A:/diags/diagnos load
c:/lunar
2. Enter the diagnostic software – from a C:\LUNAR prompt
type: diags
3. Choose option 5 Static Counter
QUALITY SYSTEM DOCUMENT Page 4 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
ii. EnCORE based systems
1. Place the scanner in Service Mode
a. Options / User Options / check the check box for
Service – Enter Password (Smile sw ver 1.0 – 2.05 or
Award ver 2.10 +)
2. Go to Tools / Diagnostics / Scanner X-ray
3. Enter desired kV and ma – click on ramp
NOTE: Be sure to use your anti-static wrist strap when working on
or near circuit board assemblies. .
5. Wedge Test (Rollover Test – DPX Series Only)
a. Select the Static Counter from the initial menu. When the static counter
screen appears, use the arrow key to move the cursor to Operating
Voltage, and enter 76.0.
b. Move the cursor to Tube Current and enter the number 150.
REV: G DATE: 2/28/02 CO: L10173
c. Set the "Repeat" number to 20 and the "Printer" to ON.
i. If the AGS is operating properly, the low channel counts will be
approximately 600,000 to 800,000 counts, and there will be fewer
high channel counts in the range of approximately 400,000 to
700,000. Both counts will be stable to approximately +/- 3000
counts from one sample to the next.
d. Place the aluminum wedge test tool on the top of the collimator, with the
thin edge toward the collimator’s larger aperture, and the thick edge away
from the aperture. Insure that the aluminum wedge is NOT in the beam.
e. Press <Esc> and the shutter will open. Allow a 7 samples to appear on
the monitor, and then slowly move the Aluminum Wedge through the
radiation beam, starting with the thin edge of the wedge.
f. Move the wedge very slowly until the beam reaches an aluminum
thickness of approximately 2 mm.
g. In the results displayed on the monitor, note the sample number where
the high channel air counts begin to be reduced. At this point the counts in
both channels should be reduced for the following samples. In other
words: both the high and low channel counts must decrease
consistently as the wedge enters the beam.
h. If the low channel counts increase at any point instead of decreasing, the
AGS is not properly adjusted or the detector is failing.
i. This may cause "bone points" or white pixels in the image around
the outside of a patient's Total Body scan and or white streaks in
femur scans.
QUALITY SYSTEM DOCUMENT Page 5 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
REV: G DATE: 2/28/02 CO: L10173
i. Run the AGS wedge test and verify that it passes attach results to PM
Check sheet.
6. Alignment verification / Mechanical / Cabling check
a. Run Air Matrix Scan
i. Remove the tabletop if it is on.
ii. In DIAGS select F4 QUA LITY ASSURANCE TESTS, select option
3 – PERFORM AIR MATRIX SCAN. Choose 1 - Perform A Scan.
Change the number of lines to the maximum value, also change
the number of steps to the maximum value.
iii. Note the filename here_____________________________. This
will have to be entered to analyze the data (filename format: XM
followed by the 4-digit system number followed by MO.01A.
Subsequent scans have extensions 01B, 01C, etc.) Then Press
Esc to continue.
iv. Remove the detec to r collimator (non-IQ / MD systems only) and
install the Air Matrix Piece (attenuation insert) or tape a 0.25 inch
piece of aluminum over the detector (over on top of the collimator)
to reduce the intensity of the beam.
v. Press Esc to begin the scan. The scan will take approx. 30
minutes to complete.
NOTE: If anything passes through the beam during this test, IT WILL FAIL.
vi. Analyze the Air Matrix scan in DIAGS by selecting option F4
QUALITY ASSURANCE TESTS then select option 4 ANALIZE AIR
MATRIX SCAN.
vii. Enter the Air Matrix file name when prompted and press the enter
key.
viii. All categories mu st pass, see table 1 for Air Matrix values.
Category Limit
Chi Squared 45
Skew +/- 0.07
Kurtosis +/- 0.07
Table 1: Failure Limits for the Air Matrix Test
ix. Print the overall values by answering Y (yes) when the software
prompts
x. Return the printout of the passing Air Matrix with the PM
Checksheet report (DXSE0038).
QUALITY SYSTEM DOCUMENT Page 6 of 10
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used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
xi. If any categories fail, check the deviation image for possible
xii. Run a Daily QA from the system software, or a Peak from the
xiii. Once an accepta ble Air Matrix scan is printed, delete the Air Matrix
b. Beam Wobble scan (Prodigy systems with software version 2.20 and
greater DXAP2011) or Alignment scan (Prodigy systems with software
versions lower than 2.20 and DPX-NT/MD+ systems- DXAP3001) as
appropriate and verify that it passes (attach the results).
7. Limit Switches
a. Verify Limit Switch distances (DPX series Diags – F1 Limit Switch
Diagnostics / 1 Limit to Limit Distance; enCORE systems - tools /
Diagnostics / scanner motion
DOC ID: DXSE0012
REV: G DATE: 2/28/02 CO: L10173
electronic or alignment problems, consult GE-Lunar OLC for
assistance.
diagnostic software, before trying the Air Matrix.
files (these files begin with "XM" or "XP" plus the System Number,
and they are generally the only files beginning with "X" in the
C:\LUNAR subdirectory).
b. DPX Series Only - Home the scanner
c. Mark the home position on the Home Jig
QUALITY SYSTEM DOCUMENT Page 7 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
(4-3)
Transverse
Steps
DPXα
10920
–
10960
DOC ID: DXSE0012
DPXIQ /
MD180 or
DPXα
w/
4.1d or
greate
r host
1078010820
DPXL
1244
0 1248
0
DPXIQ /
MD240 or
DPXL
w/
4.1d or
greate
r host
1243012470
DPXSF
1092
0 –
1096
0
REV: G DATE: 2/28/02 CO: L10173
DPXSF w/
4.1d or
greate
r host
1078010820
PRODIGY
240cm
Table
12475
+/- 25
PRODIGY
180cm
Table
12475
+/- 25
DPXNT /
MD+
240c
m
Table
12450
+/- 20
DPXNT/MD+
180cm
Table
12450
+/- 20
(1-2)
Longitudina
l Steps
(3-4)
Transverse
Steps
(2-1)
Longitudina
l Steps
13360
–
13400
10920
–
10960
13360
–
13400
w/
3.63
host
1328013320
1078010820
1328013320
1988
0 1992
0
1244
0 –
1248
0
1988
0 –
1992
0
w/
3.63
host
1973019770
1243012470
1973019770
8. Replace the table top and screw down.
a. DPX Series Only – Insure Home position is correct by using the Home Jig
b. If necessary adjust limit switches
9. Daily QA Tests
4225
–
4265
1092
0 –
1096
0
4225
4265
w/
3.63
host
41954235
1078010820
41954235
19890
+/- 35
12475
+/- 25
19890
+/- 35
13790
+/- 35
12475
+/- 20
13790
+/- 35
19605
+/- 20
12450
+/-20
19605
+/- 20
13530
+/-20
12450
+/- 20
13530
+/- 20
a. DPX Series only – check the peak setting on the QA last run
i. If peak is not 500 +/- 25 units adjust the peak
1. The voltage to the detector is controlled by the adjustment of
the potentiometer on the SBC board labeled HV ADJ - R43.
2. The voltage at TP18 of the SBC is equal to the detector
voltage divided by 1000. If R43 is adjusted to decrease the
voltage at TP18 by 0.001, the peak will increase by 5 units.
3. The last peak value obtained during a Quality Assurance
scan is stored in the Quality Assurance History database file.
QUALITY SYSTEM DOCUMENT Page 8 of 10
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This document contains confidential or proprietary information of GE Lunar. Neither the document nor the information therein is to be reproduced, distributed,
used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
DOC ID: DXSE0012
REV: G DATE: 2/28/02 CO: L10173
If the next peak value obtained differs from the last value
stored in the database by more than 50 units, the Quality
Assurance scan will fail. If the peak must be shifted by more
than 50 units to return it to 500 units +25, the peak must be
adjusted in steps of less than 50 units (40 unit steps are
recommended).
4. A complete QA must be run
5. between each step to update the Quality Assurance History
database file.
6. If the software peak setting corresponds to where both the
high and low channel counts are at a maximum, (see fig.
6.3) follow the steps outlined below. The graph on the QA
will look similar to the one shown in fig 6.3 with the dashed
vertical line (where the software thinks the peak is) on the
graph at a point where both the high and low energy plots
are maximized (the dashed curved lines). If the graph on the
QA is unlike fig 6.3, go to part B of this procedure.
7. select "Peak / Set AMP Gain", then select "Perform Peak"
and [Esc] to run the peak. Observe the results generated by
the QA to determine if the software has selected the
Amplifier Setting where both high and low channel counts
are at a maximum. If not go to part B.
8. 3. If the peak requires adjustment, (is not within +/- 25 units
of 500) connect a voltage meter to the SBC at TP18 (see fig
6.2). Put the meter to the VDC scale and record the voltage
reading (e.g. 0.703VDC
9. Using the voltage recorded in step 3 and the peak value
recorded in step 2 determine the appropriate voltage
adjustment for R43.
10. To determine voltage adjustment:
a. If Peak >500: New
/5 * + Old
b. Peak <500 New
VTP18
Old
VTP18
VTP18 = (500 – Current Peak) / 5 * –
VTP18 = (Current Peak – 500)
c. Do not attempt to adjust the peak by more than 40
units as an adjustment without a complete passing
QA in the LUNAR software will cause a peak failure
on the QA. For Peak settings that are more than 50
units away from 500 multiple adjustments are
required.
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used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
GE Medical Systems
LUNAR
b. Run two Daily QA’s and verify that they all pass (attach passing QA’s).
c. Start an additional Quality Assurance test and verify the function of the
Emergency Stop button by using it to stop the system
DOC ID: DXSE0012
REV: G DATE: 2/28/02 CO: L10173
11. With your voltmeter attached to TP 18, adjust R43 (see fig
6.2) until your voltmeter reads what you determined in step
6.
12. From the main menu press F3 System Quality Assurance
and place the System Standard on the table silk-screen with
brass insert up and at head end of table. Press[Esc] and
allow the QA to run in its entirety and to print out. Verify that
QA passes.
13. If peak value is not within 25 units of 500, record peak value
from the QA that was just run and the current voltage at TP
18. Using these values repeat steps A. 3-8 until Peak is
within 25 units of 500 and a complete passing QA has been
run.
i. Verify that all four-indicator lamps are functioning.
10. Perform an AP Spine scan of the aluminum phantom (attach results) see
DXQC0022 (DPX Series) or DXQC2022 (enCORE based systems).
a. Verify that the scanner is not “Hacksawing” – the edges on the spine
phantom image should be straight – if they are not
i. Verify that the front and rear transverse pulleys are tight
ii. Check for transverse binding
iii. If the transverse belt is loose tighten it.
iv. Prodigy Scanners – Run the Hacksaw test (DXAP2007).
b. The L2-L4 result should be within the expected range for the individual
phantom.
c. % Fat result in (water based phantoms) should be within 4 to 5%.
d. Verify that the Patient Positioning Switches and the Patient Locator Laser
are functioning.
11. Run a final Daily QA
12. Re check the last session in the error log and make sure it is free of hardware
errors.
13. Make a copy of the DEXA PM Check sheet for the customer, discuss any service
concerns with the system and explain work performed.
GENERATED RECORDS
DXSE0038 DEXA PM Quality record
QUALITY SYSTEM DOCUMENT Page 10 of 10
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used or disclosed, either in whole or in part, except as specifically authorized by GE Lunar.
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