Hologic QDR 4500 - Page 245

Appendix B – Cross-Calibration
B-3
function in QC to get an average over at least one month of QC data. Use this option
only if:
1) the QC data has been stable,
2) there has been no recent re-calibrations or field service, and
3) QC has been performed on a regular basis.
Print out the average results for Area and BMC over a recent period of stable data.
These results represent the target calibration for the NEW QDR on the
ORIGINAL PHANTOM. Write the phantom's number and "ORIGINAL QDR A/P
Array Spine Area" and "ORIGINAL QDR A/P Array Spine BMC" on the
respective Area and BMC printouts.
or
b. If QC scans have not been performed regularly or if the QC data has not been stable
for more than a month, then obtain the current ORIGINAL QDR calibration by
performing 20 Array Spine scans on the ORIGINAL PHANTOM. Add the scans to
the QC database by choosing "QC" from the main menu, then "Add" from the QC
menu, and selecting the scans from the scan selection screen. Then use AVRSCAN or
QC to obtain the current Area and BMC results from these 20 scans. Print out the
results and write the phantom's number and "ORIGINAL QDR A/P Array Spine
Area" and "ORIGINAL QDR A/P Array Spine BMC" on the respective Area and
BMC printouts.
1.2 Archive the ORIGINAL QDR's Patient Database by proceeding as follows:
a. Verify that all ORIGINAL QDR patient scans have been archived to a floppy or
optical disk. If some patient scans have not been archived, ask the operator to archive
the patient measurements. If the operator is unavailable, archive them yourself.
b. Select "dBarchive" from the menu, then press <Enter> to begin the database archive.
You will require 1, or possibly 2, blank diskettes for this procedure.
c. Insert disk 1 and press <Enter>. If required, you will be asked to insert disk 2.
d. At the completion of the database archiving, remove the diskette from the drive and
label your diskette(s) "
DB-ARCHIVE ORIGINAL QDR
".
e. Make sure the printer of the ORIGINAL QDR is turned on and properly connected.
Exit to DOS and type:
PRINT \XCDATA\ARRC.TXT<Enter>
Look for the line in
arrc.txt
which reads:
TO_N = 6.xx
where 6.xx is the ORIGINAL PHANTOM height in inches. This line is usually the
fifth line in the file. A common value is: TO_N = 6.78
Circle this line and write next to it “
original QDR array phantom height
”.
for use in Step 3.6b of the cross-calibration of the NEW QDR.