Hologic QDR 4500 User manual

HOLOGIC
Hologic Inc.
35 Crosby Drive
Bedford, MA 01730 USA
Phone in US: 800-321-4659
Fax (Domestic): 781-280-0670
Fax (International): 781-280-0671
Document # 080-0462
Revision E
MODEL QDR®4500
FAN BEAM X-RAY BONE DENSITOMETER
TECHNICAL MANUAL

ii
NOTICE
The information contained in this Manual is confidential and proprietary to Hologic, Inc. This
information is provided only to authorized representatives of Hologic's customers solely for the
purpose of facilitating the use of Hologic's products. No information contained herein may be
disclosed to any unauthorized person for any purpose whatsoever without the prior written
consent of Hologic, Inc.
Hologic QDR 4500 and the Hologic logo are registered trade marks of Hologic, Inc. All other
products and company names, used in this manual, are trademarks and registered trademarks of
other manufacturers.
The procedures described in this document are intended solely for use by direct employees of
Hologic, Inc. or authorized Hologic Equipment Resellers and their trained technicians. Any
unauthorized or untrained persons performing these procedures may affect the warranty of the
Hologic Model QDR 4500.
Exercise proper caution when servicing the system. There are dangerous and potentially lethal
voltages accessible within the QDR 4500 system. To avoid exposure to shock hazards, the Main
circuit breaker should be switched off, and the power cord removed, before working inside any
part of the system.
The QDR 4500 Fan Beam X-ray Bone Densitometer produces ionizing radiation in the form of
X-rays. It may be dangerous to the patient, operator or service technician unless safe exposure
factors and operating instructions are observed. To avoid unsafe exposure, do not attempt to
service this equipment unless you are a Hologic, Inc. certified service technician. Exercise proper
caution when servicing the system. A dosimeter (film badge) should always be worn while on
site. Dose and scatter radiation measurements must be taken after each service call to ensure that
these parameters are still within specifications.
Hologic, Inc. has made all reasonable effort to ensure that the information in this manual is
accurate and complete. Hologic, Inc. shall not, however, be liable for any technical or editorial
errors or omissions contained herein, or for incidental, special or consequential damages in
connection with the furnishing or use of this material. The information contained in this manual
is subject to change without notice.
Printed in U.S.A.
Copyright1998, 1999 by Hologic, Inc., All rights reserved

iii
RECORD OF REVISIONS
Document # 080- 0462
Date: Revision: Description:
3/95 A Release document per ECO 2501.
5/95 B Revised to include information about models QDR 4500W and QDR
4500C per ECO 2597
12/96 C Revised per ECO 3279
6/98 D Add FDA required information about system specifications (Section 1).
Add new Leakage Testing Procedure on page 3-25.
Add Reproducibility Test on page 3-27.
Add information about Radiation Measurement Report on page 3-28.
Other revisions per ECO 3822.
4/99 E Revise per ECO 4221.

iv
TABLE OF CONTENTS
SECTION 1 INTRODUCTION .....................................................................................................1-1
SYSTEM OVERVIEW.............................................................................................................................................1-1
X-RAY SCANNING THEORY................................................................................................................................1-2
FUNCTIONAL OVERVIEW....................................................................................................................................1-4
PRODUCT SPECIFICATIONS................................................................................................................................1-8
BMD Precision:...................................................................................................................................................1-10
Duty Cycle: .........................................................................................................................................................1-10
Leakage Technique Factors.................................................................................................................................1-10
Minimum Beam Filtration...................................................................................................................................1-10
Measured Half Value Layer (HVL) At Different Operating Potentials...............................................................1-11
Line Voltage and Maximum Line Current ..........................................................................................................1-11
Technique Factors for Maximum Line Current...................................................................................................1-11
Maximum Deviation............................................................................................................................................1-11
Measurement Criteria for Technique Factors......................................................................................................1-11
SECTION 2 FUNCTIONAL DESCRIPTION................................................................................2-1
COMPUTER .............................................................................................................................................................2-1
COMMUNICATIONS CONTROLLER BOARD.....................................................................................................2-1
Interface Connections............................................................................................................................................2-1
DISTRIBUTION BOARD.........................................................................................................................................2-3
Power ....................................................................................................................................................................2-3
Interface Connections............................................................................................................................................2-4
MOTOR CONTROLLER BOARD...........................................................................................................................2-5
Power ....................................................................................................................................................................2-5
Interface Connections............................................................................................................................................2-6
TZ DRIVE BOARD ..................................................................................................................................................2-7
Service Switches....................................................................................................................................................2-7
Power ....................................................................................................................................................................2-8
Interface Connections............................................................................................................................................2-8
CONTROL PANEL CONTROLLER BOARD.......................................................................................................2-11
Power ..................................................................................................................................................................2-11
Interface Connections..........................................................................................................................................2-12
C-ARM INTERFACE BOARD...............................................................................................................................2-15
Continuity Daisy Chain.......................................................................................................................................2-15
Power ..................................................................................................................................................................2-15
Interface Connections..........................................................................................................................................2-16
X-RAY CONTROLLER ASSEMBLY....................................................................................................................2-18
Interface...............................................................................................................................................................2-18
X-Ray Controller Assembly Boards....................................................................................................................2-20
I/O and Logic Board .......................................................................................................................................2-20
Low Voltage Power Supply............................................................................................................................2-20
Power Factor Regulator (PFR) Substitution Board.........................................................................................2-21
Duty Cycle Regulator......................................................................................................................................2-21
H-Bridge Board...............................................................................................................................................2-21
Interface Connections .....................................................................................................................................2-21
X-RAY SOURCE UNIT..........................................................................................................................................2-26
DATA ACQUISITION SYSTEM ...........................................................................................................................2-26
Solid State Detector.............................................................................................................................................2-27
Power..............................................................................................................................................................2-27
Interface Connections .....................................................................................................................................2-27
INTEGRATOR/MULTIPLEXOR BOARD............................................................................................................2-28
Power..............................................................................................................................................................2-29
Interface Connections .....................................................................................................................................2-29
Analog To Digital Board.....................................................................................................................................2-30
Power..............................................................................................................................................................2-31

v
Interface Connections......................................................................................................................................2-31
POWER MODULE .................................................................................................................................................2-32
SECTION 3 INSTALLATION.......................................................................................................3-1
REQUIRED TOOLS..................................................................................................................................................3-1
REQUIRED DOCUMENTATION............................................................................................................................3-1
ROOM AND DOORWAY SIZE...............................................................................................................................3-2
ARRANGE FOR HELP.............................................................................................................................................3-4
INSPECT FOR VISIBLE SHIPPING DAMAGE .....................................................................................................3-4
UNCRATE UNIT......................................................................................................................................................3-5
INSPECT FOR HIDDEN SHIPPING DAMAGE .....................................................................................................3-6
TAKE INVENTORY.................................................................................................................................................3-6
MEASURE PATH TO FINAL DESTINATION.......................................................................................................3-6
Short Doorway.......................................................................................................................................................3-6
Narrow Hallway.....................................................................................................................................................3-7
REMOVE TABLE TOP (IF NECESSARY).............................................................................................................3-7
REMOVE QDR 4500A, OR SL, C-ARM (IF NECESSARY)..................................................................................3-8
PREPARING THE TABLE TOP FOR MOVING (SL only) ..................................................................................3-10
MOVE UNIT TO DESTINATION (VERTICAL POSITION)................................................................................3-10
MOVE UNIT TO DESTINATION (HORIZONTAL POSITION)..........................................................................3-11
SET UP UNIT..........................................................................................................................................................3-13
INSTALL QDR 4500A, OR QDR 4500SL, UPPER C-ARM.................................................................................3-15
INSTALL QDR 4500W, OR QDR 4500C, C-ARM................................................................................................3-16
INSTALL COMPUTER ..........................................................................................................................................3-17
INSTALL CABLES.................................................................................................................................................3-17
SAFETY PRECAUTIONS......................................................................................................................................3-18
CHECK POWER LINE VOLTAGE........................................................................................................................3-18
Measure Line Voltage .........................................................................................................................................3-18
Measure Isolation Transformer Secondary Voltage.............................................................................................3-18
CHECK TUBE KV PEAK POTENTIAL................................................................................................................3-19
CHECK TUBE CURRENT.....................................................................................................................................3-21
CHECK BELT TENSION.......................................................................................................................................3-23
ADJUST C-ARM Y BELT......................................................................................................................................3-23
CALIBRATE MOTORS..........................................................................................................................................3-23
CHECK X-RAY BEAM ALIGNMENT..................................................................................................................3-23
CALIBRATE APERTURE (QDR 4500A AND SL)...............................................................................................3-23
CHECK LASER POSITIONING OFFSET.............................................................................................................3-24
ADJUST A/D GAIN CONTROL.............................................................................................................................3-24
PERFORM BEAM FLATTENING.........................................................................................................................3-24
PERFORM LATERAL ALIGNMENT TEST.........................................................................................................3-24
MEASURE X-RAY DOSE TO PATIENT..............................................................................................................3-24
CHECK HVPS/S (TANK) FOR RADIATION LEAKAGE....................................................................................3-25
CALIBRATE FOR AREA, BMD AND BMC.........................................................................................................3-26
TEST SCAN MODES .............................................................................................................................................3-26
FINISH ASSEMBLING UNIT................................................................................................................................3-26
MEASURE X-RAY SCATTER FROM PHANTOM..............................................................................................3-27
PERFORM QC........................................................................................................................................................3-27
RUN REPRODUCIBILITY TEST..........................................................................................................................3-27
THE RADIATION MEASUREMENT REPORT....................................................................................................3-29
SECTION 4 ALIGNMENT AND CALIBRATION.........................................................................4-1
TABLE ALIGNMENT ..............................................................................................................................................4-1
Checking Table Alignment....................................................................................................................................4-1
Aligning Table.......................................................................................................................................................4-1
Table Edge to T-Rail (“A” Dimension) Adjustment.........................................................................................4-1
Front to Back T-Rail and Table Edge/Rail Gap Adjustment.............................................................................4-3
C-ARM PARALLELISM ADJUSTMENT (A and SL only).....................................................................................4-3
X-RAY BEAM ALIGNMENT (A and SL only) .......................................................................................................4-4
X-RAY BEAM ALIGNMENT (C and W only) ........................................................................................................4-8

vi
APERTURE CALIBRATION (A and SL only)........................................................................................................4-9
MOTOR CALIBRATION.........................................................................................................................................4-9
MOTOR$TZ (QDR 4500A and SL) ...................................................................................................................4-10
MOTOR$AY (all QDR 4500 models) ................................................................................................................4-12
MOTOR$TY (QDR 4500A and W)....................................................................................................................4-16
MOTOR$TX (all QDR 4500 models).................................................................................................................4-19
MOTOR$AR (QDR 4500A and SL)...................................................................................................................4-22
LASER POSITIONING OFFSET ADJUSTMENT.................................................................................................4-27
A/D GAIN CONTROL ADJUSTMENT.................................................................................................................4-27
BEAM FLATTENING............................................................................................................................................4-28
X-RAY BEAM ALIGNMENT "AIRSCAN" TEST...............................................................................................4-30
Machines using Body Composition Analysis (BCA)..........................................................................................4-31
Machines using BMD Whole Body Analysis......................................................................................................4-31
LATERAL ALIGNMENT TEST (QDR 4500A AND SL)......................................................................................4-31
AREA, BMD AND BMC CALIBRATION.............................................................................................................4-33
Scan Thickness Measurement & Calibration (QDR 4500A and SL)..................................................................4-33
Scan Thickness Measurement & Calibration (QDR 4500W and C)....................................................................4-36
Calibration of Area and BMC, for Array Scan Modes........................................................................................4-38
Adding Array AP Scans to the QC Database.......................................................................................................4-39
SECTION 5 REMOVE AND REPLACE PROCEDURES............................................................5-1
RECOMMENDED TOOLS ......................................................................................................................................5-1
ELECTRONICS TRAY FRUS..................................................................................................................................5-1
Electronics Tray Printed Circuit Boards................................................................................................................5-1
C-Arm Y Belt........................................................................................................................................................5-2
C-Arm Y Motor or Gearcase.................................................................................................................................5-3
C-Arm Y Encoder .................................................................................................................................................5-4
CONTROL PANEL AND TABLE Y FRUS.............................................................................................................5-4
Control Panel.........................................................................................................................................................5-5
PCBs Under Right-Side of the Table....................................................................................................................5-5
Table Y Belt..........................................................................................................................................................5-6
Table Y Motor or Gearcase...................................................................................................................................5-6
Table Y Encoder....................................................................................................................................................5-7
TABLE X FRUS........................................................................................................................................................5-8
Table X Motor Controller PCB.............................................................................................................................5-8
Table X Belt..........................................................................................................................................................5-9
Table X Motor or Gearcase.................................................................................................................................5-10
Table X Encoder .................................................................................................................................................5-10
TABLE Z FRUS (A and SL only) ...........................................................................................................................5-11
Pedestal ...............................................................................................................................................................5-11
Linear Potentiometer (Encoder- Obsolete)..........................................................................................................5-13
The Linear Rotary String (Encoder)....................................................................................................................5-13
Installation ......................................................................................................................................................5-13
ARM R FRUS .........................................................................................................................................................5-15
Motor Controller Board.......................................................................................................................................5-15
Arm R Belt..........................................................................................................................................................5-16
Arm R Motor, Gearcase, Encoder or Encoder Belt.............................................................................................5-16
Gas Spring...........................................................................................................................................................5-18
LOWER C-ARM FRUS..........................................................................................................................................5-18
C-Arm Interface Board........................................................................................................................................5-18
X-Ray Controller Assembly................................................................................................................................5-18
Filter Drum Assembly.........................................................................................................................................5-20
Tank Assembly....................................................................................................................................................5-21
UPPER C-ARM FRUS............................................................................................................................................5-23
Integrator/Multiplexor Board..............................................................................................................................5-23
Detector Boards...................................................................................................................................................5-24
Laser Assembly...................................................................................................................................................5-25
REAR C-ARM FRUS..............................................................................................................................................5-26

vii
Analog to Digital Converter Board......................................................................................................................5-26
POWER MODULE FRUS.......................................................................................................................................5-27
28 Volt Power Supply.........................................................................................................................................5-27
±15 Volt Power Supply.......................................................................................................................................5-28
Line Filter............................................................................................................................................................5-29
Isolation Transformer ..........................................................................................................................................5-29
Power Controller Board.......................................................................................................................................5-29
OPERATOR'S CONSOLE FRUS ...........................................................................................................................5-30
APERTURE ASSEMBLY FRUS............................................................................................................................5-32
Aperture Stepper Motor.......................................................................................................................................5-32
Aperture Motor PCB ...........................................................................................................................................5-33
Aperture Position Belt.........................................................................................................................................5-33
Rotary Potentiometer...........................................................................................................................................5-34
DRUM ASSEMBLY FRUS ....................................................................................................................................5-34
Drum Encoder PCB.............................................................................................................................................5-34
Drum Belts ..........................................................................................................................................................5-35
Stepper Motor Assembly.....................................................................................................................................5-36
Drum Bearings.....................................................................................................................................................5-37
REPLACING EMI CABLES...................................................................................................................................5-39
FRU LISTS..............................................................................................................................................................5-41
Figure 5-1. Electronics Tray FRUs......................................................................................................................5-41
Figure 5-2. Control Panel and Table Y FRUs .....................................................................................................5-41
Figure 5-3. Left Side Table Y FRUs....................................................................................................................5-41
Figure 5-4. Table X FRUs...................................................................................................................................5-42
Figure 5-5. Table Z FRUs....................................................................................................................................5-42
Figure 5-6. Installing the Rotary String Encoder.................................................................................................5-42
Figure 5-7 C-Arm R FRUs (Outside View).........................................................................................................5-42
Figure 5-8. C-Arm R FRUs (Inside View) ..........................................................................................................5-43
Figure 5-9. Lower C-Arm FRUs..........................................................................................................................5-43
Figure 5-11. Upper C-Arm FRUs........................................................................................................................5-43
Figure 5-12. Detector Assembly Mounting .........................................................................................................5-43
Figure 5-13. Laser Assembly...............................................................................................................................5-44
Figure 5-14. Rear C-Arm FRUs ..........................................................................................................................5-44
Figure 5-15. Power Module FRUs ......................................................................................................................5-44
Figure 5-16. Power Control Panel FRUs.............................................................................................................5-44
Figure 5-17. Operator's Console Assemblies.......................................................................................................5-45
Figure 5-18. Computer Assemblies.....................................................................................................................5-46
Figure 5-19. Aperture Assembly FRUs (QDR 4500A and SL)...........................................................................5-46
Figure 5-22. Front Drum Assembly FRUs...........................................................................................................5-46
Figure 5-23. Drum Outer Bearings......................................................................................................................5-47
Figure 5-24. Drum Inner Bearings.......................................................................................................................5-47
Cables..................................................................................................................................................................5-47
Miscellaneous......................................................................................................................................................5-47
Mobile.................................................................................................................................................................5-48
Special Tools.......................................................................................................................................................5-48
SECTION 6 FAULT ISOLATION.................................................................................................6-1
BEFORE STARTING................................................................................................................................................6-1
SOFTWARE CONFIGURATION.............................................................................................................................6-1
HARDWARE CONFIGURATION...........................................................................................................................6-1
POWER PROBLEMS ...............................................................................................................................................6-1
MOTION PROBLEMS..............................................................................................................................................6-2
CONTROL PANEL PROBLEMS.............................................................................................................................6-5
DISPLAY PROBLEMS.............................................................................................................................................6-5
Vertical Stripe........................................................................................................................................................6-6
Horizontal Stripe ...................................................................................................................................................6-6
Noise......................................................................................................................................................................6-6
No Display.............................................................................................................................................................6-7

viii
TARGETING/LASER PROBLEMS.........................................................................................................................6-8
DATA COMMUNICATIONS PROBLEMS.............................................................................................................6-8
AREA /BMD/BMC/CV SPECIFICATION PROBLEMS.........................................................................................6-9
X-RAY PROBLEMS.................................................................................................................................................6-9
No X-Rays.............................................................................................................................................................6-9
X-Ray Alignment Problems ................................................................................................................................6-10
Beam Flattening Problems ..................................................................................................................................6-11
LASER PROBLEMS...............................................................................................................................................6-12
OIL LEAKAGE.......................................................................................................................................................6-13
The Torque Specifications...................................................................................................................................6-13
Tank Top Cover Components and Screw Location.............................................................................................6-13
Tightening the Lexan Cup Screws.......................................................................................................................6-14
Tightening the Bladder Gasket Screws................................................................................................................6-14
Tightening the Transformer Seal Screws.............................................................................................................6-14
Tightening the Tank Cover Gasket Screws..........................................................................................................6-15
MISCELLANEOUS PROBLEMS ..........................................................................................................................6-16
MESSAGES ............................................................................................................................................................6-16
NO A/C LINE INTERRUPTS.................................................................................................................................6-17
ERROR MESSAGE LIST.......................................................................................................................................6-19
SECTION 7 PREVENTIVE MAINTENANCE...............................................................................7-1
CUSTOMER PREVENTIVE MAINTENANCE......................................................................................................7-1
FIELD SERVICE PREVENTIVE MAINTENANCE...............................................................................................7-1
Guide Rail and Bearing Maintenance....................................................................................................................7-2
SECTION 8 PCB SUMMARY INFORMATION...........................................................................8-1
Power Distribution................................................................................................................................................8-1
ADC ......................................................................................................................................................................8-1
Signal Distribution................................................................................................................................................8-2
Communications Controller ..................................................................................................................................8-2
Detector Array Assembly......................................................................................................................................8-3
TZ Drive................................................................................................................................................................8-3
Stepper Motor Controller......................................................................................................................................8-4
Control Panel Controller.......................................................................................................................................8-4
SECTION 9 SOFTWARE TOOLS...............................................................................................9-1
SUSQ ....................................................................................................................................................................9-1
SQKEYPAD .........................................................................................................................................................9-4
APPENDIX A SOFTWARE DEINSTALLATION/INSTALLATION...................................................1
APPENDIX B CROSS-CALIBRATION............................................................................................1

ix
TABLE OF FIGURES
Figure 1-1. QDR4500 ................................................................................................................1-2
Figure 1-2. Q Scan Plot.................................................................................................................1-3
Figure 1-3. QDR 4500 Block Diagram (Operator's Console).......................................................1-4
Figure 1-4. QDR 4500 Block Diagram (Scanner Unit) ................................................................1-5
Figure 1-5. QDR 4500 Block Diagram (C-Arm Subsystem)........................................................1-6
Figure 2-1. Communications Controller Board/Distribution Board Interconnection Diagram....2-3
Figure 2-2. Distribution Board High Level Interconnection Diagram..........................................2-4
Figure 2-3. Distribution Board/Motor Controller Board Interconnection Diagram.....................2-6
Figure 2-4. Distribution Board/TZ Drive Board Interconnection Diagram..................................2-9
Figure 2-5. Control Panel Controller Interconnection Diagram...............................................2-12
Figure 2-6. Distribution Board/C-Arm Interface Board Interconnection Diagram ....................2-16
Figure 2-7. C-Arm Interface Board High Level Interconnection Diagram................................2-18
Figure 2-8. C-Arm Interface Board/X-Ray Controller Assembly Interconnection Diagram....2-19
Figure 2-9. X-Ray Controller Assembly High-Level Interconnection Diagram........................2-21
Figure 2-10. Low Voltage Power Supply Board Interconnections............................................2-22
Figure 2-11. PFR Substitution Board/I/O and Logic Board Interconnection Diagram .............2-24
Figure 2-12. I/O and Logic Board/H-Bridge Board Interconnection Diagram..........................2-24
Figure 2-13. I/O and Logic Board/Duty Cycle Driver Board Interconnection Diagram...........2-25
Figure 2-14. H-Bridge Board/Duty Cycle Driver Board Interconnection Diagram...................2-25
Figure 2-15. Integrator/Multiplexor Board/Solid State Detector Boards Interconnection Diagram2-27
Figure 2-16. Analog Digital Converter Board/Integrator Multiplexor Board Interconnection
Diagram..................................................................................................................2-29
Figure 2-17. C-Arm Interface Board/Analog/Digital Converter Board Interconnection Diagram2-31
Figure 2-18. Power Module Block Diagram..............................................................................2-33
Figure 3-1. Room Layout (4500A) ...............................................................................................3-2
Figure 3-2. System Dimensions (4500SL)....................................................................................3-3
Figure 3-3. System Dimensions (4500W).....................................................................................3-3
Figure 3-4. System Dimensions (4500C)......................................................................................3-4
Figure 3-5. Crated Unit (QDR 4500A and QDR 4500SL) ...........................................................3-5
Figure 3-6. Uncrated Unit (QDR 4500A and QDR 4500 SL) ......................................................3-7
Figure 3-7. Table X Drive.............................................................................................................3-8
Figure 3-8. Tipping Unit ...............................................................................................................3-9
Figure 3-9. Moving and Tilting the Unit Down..........................................................................3-11
Figure 3-10. Auxiliary Horizontal Caster Installation................................................................3-12
Figure 3-11. Shipping Bracket Locations (QDR 4500A and SL)...............................................3-13
Figure 3-12. Shipping Bracket Locations (QDR 4500A and SL)...............................................3-14
Figure 3-13. Shipping Bracket Locations (QDR 4500W and C)................................................3-14
Figure 3-14. Shipping Bracket Location (QDR 4500W and C)..................................................3-15
Figure 3-15. Repositioning the Belt Tensioning Mechanism.....................................................3-16
Figure 3-16. Isolation Transformer Taps....................................................................................3-17
Figure 3-17. Peak Potential Mode 4............................................................................................3-20
Figure 3-18. Peak Potential Mode 3............................................................................................3-20
Figure 3-19. Tube Current Mode 1.............................................................................................3-22

x
Figure 3-20. Tube Current Mode 3 .............................................................................................3-22
Figure 3-21. Leakage Test Shield (099-0566) ............................................................................3-25
Figure 4-1. Table Alignment.........................................................................................................4-2
Figure 4-2. Pedestal (covers removed)..........................................................................................4-3
Figure 4-3. X-Ray Alignment Fixture (010-0923)........................................................................4-4
Figure 4-4. Inserting The X-Ray Alignment Fixture ....................................................................4-5
Figure 4-5. The Alignment Fixture Properly Installed..................................................................4-6
Figure 4-6. Filter Drum Adjustments - Top View ........................................................................4-6
Figure 4-7. Array Assembly - Top View, Partial..........................................................................4-7
Figure 5-1. Electronics Tray FRUs...............................................................................................5-3
Figure 5-2. Control Panel and Table Y FRUs...............................................................................5-5
Figure 5-3. Left Side Table Y FRUs.............................................................................................5-7
Figure 5-4. Table X FRUs.............................................................................................................5-9
Figure 5-5. Table Z FRUs...........................................................................................................5-12
Figure 5-6. Installing the Rotary String Encoder........................................................................5-14
Figure 5-7 C-Arm R FRUs (Outside View)................................................................................5-15
Figure 5-8. C-Arm R FRUs (Inside View)..................................................................................5-17
Figure 5-9. Lower C-Arm FRUs.................................................................................................5-20
Figure 5-10. Top View of Tank ..................................................................................................5-22
Figure 5-11. Upper C-Arm FRUs................................................................................................5-24
Figure 5-12. Detector Assembly Mounting.................................................................................5-25
Figure 5-13. Laser Assembly......................................................................................................5-26
Figure 5-14. Rear C-Arm FRUs..................................................................................................5-27
Figure 5-15. Power Module FRUs..............................................................................................5-28
Figure 5-16. Power Control Panel FRUs ....................................................................................5-30
Figure 5-17. Operator's Console Assemblies..............................................................................5-31
Figure 5-18. Computer Assemblies.............................................................................................5-32
Figure 5-19. Aperture Assembly FRUs (QDR 4500A and SL)..................................................5-33
Figure 5-20. Aperture Assembly Removal (QDR 4500A and SL).............................................5-35
Figure 5-21. Rear Drum Assembly FRUs...................................................................................5-36
Figure 5-22. Front Drum Assembly FRUs..................................................................................5-37
Figure 5-23. Drum Outer Bearings .............................................................................................5-38
Figure 5-24. Drum Inner Bearings..............................................................................................5-39
Figure 5-25. The EMI Compliance Cable...................................................................................5-40
Figure 6-1. Scanner Motion Directions.........................................................................................6-3
Figure 6-2. Checking C-Arm Parallelism....................................................................................6-10
Figure 6-3 Tank Assembly Top view..........................................................................................6-13
Figure 6-4 Lexan Cup Screw Tightening Order..........................................................................6-14
Figure 6-5. Bladder Gasket Screws.............................................................................................6-14
Figure 6-6. Transformer Screws .................................................................................................6-15
Figure 6-7. Tank Cover Gasket...................................................................................................6-16
Figure 7-1. Guide Bearing and Rail..............................................................................................7-3
Figure 9-1. SUSQ Screen−X-Rays OFF .......................................................................................9-2
Figure 9-2. SUSQ Screen−X-Rays ON.........................................................................................9-2
Figure 9-3. SUSQ Screen Settings................................................................................................9-3

1-1
SECTION 1
INTRODUCTION
SYSTEM OVERVIEW
The Hologic QDR4500 X-ray Bone Densitometer (Figure 1-1) estimates the bone mineral
content (BMC) and bone mineral density (BMD) of selected areas of the body, or of the entire
skeleton. It does so using X-rays of two different energy levels. This dual-energy scheme allows
soft tissue within the selected area to be subtracted out, leaving only bone to be scanned and
estimated.
Note: This manual uses "QDR 4500" to refer to all models in the QDR 4500 series systems.
Information presented in this manual, that applies only to a particular model, or models,
will be noted as such.
The patient lies face up on the table and, with the aid of a cross-hair laser, the operator positions
the scanning arm over the region of interest. After entering patient data and selecting the type
and size of scan desired, the operator initiates the scan with a single keystroke.
The operator is not required to select technique factors, as tube current and voltage are pre-
selected and fixed. Since testing is performed by fan beam method rather than by flooding the
area as in conventional radiography, the scanning time is a function of the dimensions of the area
to be measured, the desired resolution and the desired precision.
BMC results are expressed in grams of calcium hydroxyapatite, and BMD is reported in
grams/cm2of the same compound.
Note: In most cases, no additional shielding is necessary for patient, operator or room, and the
QDR 4500 can be placed in any convenient non-shielded examination room. Contact your
state regulatory agency for details about additional shielding requirements, if any.
The QDR 4500 employs a patented Automatic Internal Reference System, which continuously
calibrates the machine to eliminate the effects of variations in temperature, tube flux, etc. No
daily calibration is required. The daily scanning of a quality control phantom is required to
provide assurance that the system is functioning correctly, and to aid in the detection of any long-
term drift.
The X-ray scans produced by the QDR 4500, and displayed on the monitor, are intended only to
locate anatomical sites for measurement, and to assure the operator that the machine is operating
properly. They are not intended as a substitute for conventional film-based diagnostic scans.

QDR®4500 Technical Manual
1-2
Scanner Unit
Operator's Console
Figure 1-1. QDR

4500
X-RAY SCANNING THEORY
An X-ray source, consisting of a generator and tube in a common, shielded enclosure, is mounted
beneath the patient. It generates a narrow, tightly collimated, fan shaped beam of X-rays which
alternate, at power line frequency, between 100kVp and 140kVp. The source is at one end of a
C-arm. At the other end, above the patient, is a crystal/solid state detector. During a scan, the C-
arm and table move under computer control to guide the beam over the desired scan area.
Before passing through the patient, the beam is filtered through a rotating drum, in which
alternating segments have radio-opacities equivalent to tissue, bone and air. When finally
intercepted by the detector, the beam contains information about the X-ray absorbing
characteristics of both the patient and the calibration materials in the filter drum. An A/D
converter, fed by the detector, supplies a complex digital signal to the computer, which uses that
signal both to construct the screen display and as the basis for its computations of BMC and
BMD.
The QDR 4500 computer algorithm is based on the principle that bone attenuates the X-ray beam
differently at high and low energies. The bone mineral content of any sample point can be
computed from:
Q = L - kH
where H and L are the logarithms of the sample attenuation at high (140kVp) and low (100kVp)
energies, respectively, and the constant k depends on the tissue attenuation characteristics of the
beam. In the QDR 4500, k is continuously measured using the “tissue” segment in the filter
wheel.

Section 1 - Introduction
1-3
The program works in the following manner:
1. Load preliminary scan and obtain regions of interest from operator.
2. Estimate k as an average value of:
k = [Ltissue - Lair] / [Htissue - Hair]
where Ltissue indicates a low-energy measurement with tissue-equivalent material
interposed by the filter drum, and Lair, Htissue and Hair are similarly defined.
Note: The subscript "air" designates the filter drum segment that is empty (i.e., contains neither
bone- nor tissue-equivalent material).
3. Using this value of k, calculate Q for each point scanned using the formula given above
(Q = L - kH). This array of Q values constitutes a "Q scan". Displays the Q scan.
4. Compile a histogram of the Q values. Because a large portion of the scan contains soft
tissue only, this histogram will have a large peak. Choose a threshold value just above
this peak, and apply that value to discriminate, point by point in the Q scan, between
"bone" points (whose Q is above the threshold) and "non-bone" points (whose Q is
below the threshold).
Figure 1-2. Q Scan Plot
5. Use the "non-bone" points to calculate a baseline value for each scan line. Using these
points, form a new histogram and repeat steps 4 and 5 until the results converge.
6. Smooth the segment boundaries to eliminate isolated noise-generated "bone" points.
7. Display the "bone" and "non-bone" points for operator approval.
8. Determine the constant of proportionality (d0) that relates the Q values to actual BMC
(grams). That constant is determined by measuring how much Q shifts when bone-
equivalent material is interposed by the filter drum.
9. Calculate the total bone mineral values by adding up the Q values for all "bone" points
in each region of interest (e.g., each vertebra), and multiplying by d0.
10. Determine the bone areas by counting the number of "bone" points in each region of
interest.
11. Calculate bone mineral density as:

QDR®4500 Technical Manual
1-4
BMD = BMC / area
12. Display the calculated results and print the report.
FUNCTIONAL OVERVIEW
This section provides a block diagram of the QDR 4500 system along with a brief functional
overview description of each block. A detailed functional description along with interconnection
diagrams and interconnection descriptions is provided in Section 2.
KEYBOARD
MOUSE
DISPLAY
TERMINAL
PRINTER
POWER
STRIP
COMMUNICATIONS
CONTROLLER
TO/FROM
INSTRUMENT
DISTRIBUTION
(FIGURE 1.4)
POWER
ASSEMBLY
15/24V EMERGENCY
28V DC
TO X-RAY CONTROLLER (FIGURE 1.5)
AC IN
VGA
SCSI INTERFACE
OPTICAL DISK
(
OPTIONAL
)
Computer
AC
AC AC
MODEM
(OPTIONAL) PHONE
JACK
TO/FROM LEFT/RIGHT PEDESTAL DRIVE (FIGURE 1.4)
Figure 1-3. QDR 4500 Block Diagram (Operator's Console)

Section 1 - Introduction
1-5
DISTRIBUTION
CONTROL
PANEL
CONTROLLER
TZ DRIVE
MOTOR
CONTROLLER
TX STEPPER
MOTOR
DRIVER
TY STEPPER
MOTOR
DRIVER
AR STEPPER
MOTOR
DRIVER
AY STEPPER
MOTOR
DRIVER
PEDESTAL LEFT
MOTOR AND
POSITION ENCODER
C_ARM CARRIAGE
MOTOR AND
POSITION ENCODER
C_ARM ROTATION
MOTOR AND
POSITION ENCODER
PEDESTAL RIGHT
MOTOR AND
POSITION ENCODER
TABLE LEFT/RIGHT
MOTOR AND
POSITION ENCODER
TABLE IN/OUT
MOTOR AND
POSITION ENCODER
CONTROL PANEL
TO/FROM C-ARM INTERFACE (FIGURE 1-5)
TO/FROM
COMMUNICATION
CONTROLLER
15/24V
EMERGENCY
LEFT/RIGHT PEDESTAL
28V DC
TO/FROM
POWER
MODULE
Figure 1-4. QDR 4500 Block Diagram (Scanner Unit)

QDR®4500 Technical Manual
1-6
C-ARM
INTERFACE
ANALOG TO
DIGITAL
CONVERTER
INTEGRATOR
MULTIPLEXOR SILICON DETECTORS
X_RAY
SOURCE
UNIT
X_RAY
CONTROLLER
APERTURE
MOTOR AND
SENSOR
LASER
ASSEMBLY
DRUM
MOTOR AND
ENCODER PICKUP
TO/FROM
DISTRIBUTION
FROM POWER MODULE
Figure 1-5. QDR 4500 Block Diagram (C-Arm Subsystem)
Block Description
Computer Controls and commands all QDR 4500 hardware modules.
Communications
Controller Controls the flow of commands to and from the Scanner modules via the communications bus.
Distribution Board Provides the interconnections between the QDR 4500 Operator's Console
and the Scanner.
Control Panel
Controller Interfaces the Scanner’s Control Panel to the Operator's Console computer software.
Control Panel Provides switches (with visual indicators) for moving the Scanner’s C-
Arm and Patient Table. Also provides an Emergency Stop switch.
TZ Drive Motor
Controller Controls the motion of the Patient’s Table left and right pedestal motors based on commands from the computer software.

Section 1 - Introduction
1-7
Table Up/Down
Motor and Position
Encoder
Raises or lowers the Patient Table and provides position monitoring.
TX Stepper Motor
Driver Controls the motion of the Patient’s Table in and out motor based on commands from the computer software.
Table In/Out Motor
and Position
Encoder
Moves the Patient Table in and out and provides position monitoring.
TY Stepper Motor
Driver Controls the motion of the Patient’s Table left and right motor based on commands from the computer software.
Table Left/Right
Motor and Position
Encoder
Moves the Patient Table left and right and provides position monitoring.
AR Stepper Motor
Driver Controls the motion of the C-Arm rotation motor based on commands from the computer software.
C-Arm Rotation
Motor and Position
Encoder
Rotates the C-Arm and provides position monitoring.
AY Stepper Motor
Driver Controls the motion of the C-Arm left and right motor based on commands from the computer software.
C-Arm AY Motor
and Position
Encoder
Moves the C-Arm left and right and provides position monitoring.
C-Arm Interface Controls the Aperture and Filter Drum motors, generates timing signals
for the X-Ray Controller and the Data Acquisition System, and provides
power to the Positioning Laser.
X-Ray Controller Controls the operation of the X-ray source.
X-Ray Source Unit Generates the X-ray beam.
Solid State Detectors Converts the X-rays into electrical signals.
Integrator/
Multiplexor Integrates the signals from the Solid State Detectors and applies them to the Analog to Digital Converter.
Analog to Digital
Converter Converts the analog signals from the Integrator/Multiplexor to a digital format.
Positioning Laser Provides a laser beam to assist in positioning the patient on the Patient
Table.

QDR®4500 Technical Manual
1-8
PRODUCT SPECIFICATIONS
SPECIFICATION MODEL DEFINITION
Scanning Method: A,SL Multidetector array, Indexing table, and motorized C-arm
W,C Multidetector array, Indexing table, and Arm
X-ray System: All Switched Pulse Dual-Energy X-ray tube, operating at 100 and 140kV, 5mA avg. at 50% duty cycle, 2.5mA avg. at 25% duty cycle,
30s maximum, Tungsten target
Detector System: A216 multichannel detector consisting of CdWO4scintillators
coupled to Silicon diodes
SL 128 multichannel detector consisting of CdWO4scintillators
coupled to Silicon diodes
C,W 64 multichannel detector consisting of CdWO4scintillators coupled
to Silicon diodes
Scanning Sites: ALumbar spine (in AP and lateral projections), proximal femur (hip),
and whole body
SL Lumbar spine (in AP and lateral projections), proximal femur (hip)
W Lumbar spine, proximal femur (hip), and whole body
C Lumbar spine, proximal femur (hip)
Scan Region: A,W 195cm (76.77") x 65cm (25.59")
SL 96cm (38") x 65cm (25.59")
C 96cm (38") x 51cm (20")
Scatter Radiation:
All
Less than 10µGy/h (1mrad/h) at 2m (79 in.) from the center of the
X-ray beam for all scans except images, which is less than
10µGy/h (1mrad/h) at 3.5m (138 in.) from the center of the X-ray
beam.
Leakage
Radiation: All The QDR-4500 meets the requirements of 21 CFR 1020.30(k) for leakage from the X-ray source
External Shielding
Requirement: All Contact state regulatory agency.
Calibration: All Self Calibrating using HOLOGIC Automatic Internal Reference
System. Operator calibration NOT required.
System Weight: Scanner Console
A 365kg 800lb
SL 365kg 800lb
W 310kg 680lb
(installed)
C 295kg 650lb
68kg 150lb
System
A 660kg 1450lb
SL 660kg 1450lb
W 622kg 1370lb
(shipping)
C 610kg 1340lb

Section 1 - Introduction
1-9
SPECIFICATION MODEL DEFINITION
Operating
Temperature: All 15o- 32oC (60o- 90oF)
Humidity: All 20 - 80% relative Humidity, non-condensing
Footprint: Length Width Height
m inches m inches m inches
C-arm not
rotated, table not
extended A 2.02 79.5 1.40 55 1.42 56
C-arm rotated,
table extended A 3.02 119 1.50 59 1.42 56
C-arm not rotated SL 2.02 79.5 1.40 55 1.42 56
C-arm rotated SL 2.02 79.5 1.50 59 1.42 56
table extended W 3.02 119 1.50 59 1.42 56
table not
extended W 2.02 79.5 1.22 48 1.42 56
C 2.02 79.5 1.40 55 1.42 56
Average Heat
Load: ALL 1000w (3400 BTU/hr)
A,SL Adjustable, 71cm (28") from floor when scanning in AP mode
Patient Table
Height: W,C 71cm (28”)
Positioning Laser: All Laser Diode (<1mW) cross hair, with emergency mechanical
shutter
A,SL Selectable by scan type
X-ray Collimation: W,C 1.0mm slit
A,SL Exam table is capable of moving +/-2.54cm (1.0") in the x-axis
from center location with scan arm in lateral position.
Lateral Tracking: C,W N/A
Leakage Current: All Normal <75µA Single Fault <400µA
A/SL 1 line pair/mm (approximately 0.5mm)
Resolution: C/W 0.5 line pair/mm (approximately 1.0mm)

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1-10
BMD Precision:
SCAN TIME DOSE
EXAM MODEL (seconds) in vivo PRECISION mGy mrad
AP Spine Array All 60 1.0% 0.20 20.0
AP Spine Fast All 30 1.5% 0.10 10.0
AP Spine High Definition A,SL 120 1.0% 0.20 20.0
AP Spine Turbo A,SL 10 2.0% 0.07 7.0
W,C 15 2.0% 0.05 5.0
Forearm A,SL 30 1.0% 0.05 5.0
W,C 30 1.0% 0.10 10.0
Hip Array All 60 1.0% 0.20 20.0
Hip Fast All 30 1.5% 0.10 10.0
Hip High Definition A,SL 120 1.0% 0.20 20.0
Hip Turbo A,SL 10 2.0% 0.07 7.0
W,C 15 2.0% 0.05 5.0
Lateral Spine Array A,SL 240 1.0% 0.70 70.0
Lateral Spine Fast A,SL 120 1.0% 0.35 35.0
Lateral Spine High Def. A,SL 240 1.0% 0.70 70.0
Whole Body A 180 1.0% 0.01 1.0
W 407 1.0% 0.015 1.5
Duty Cycle:
A50% for all scan modes except Whole Body
100% for Whole Body scans
SL,W,C 50% for all Scan Modes
Leakage Technique Factors
The leakage technique factors for all models of QDR 4500’s are the same. It is the maximum
continuous current at the maximum peak potential. This is X-ray mode #3. Peak potential
140/100kVp. (dual energy), current 10mA peak 25% duty cycle or 2.5mA average.
Minimum Beam Filtration
The minimum filtration permanently in the beam is 3.7mm Al equivalent @80kV.