Hologic QDR 4500 - Calibration of Area and BMC, for Array Scan Modes

QDR

4500 Technical Manual
4-38
16. Press "X" <Enter> to EXIT the FSCAL program.
Calibration of Area and BMC, for Array Scan Modes
After the machine has been calibrated for thickness measurement in the array mode, it must be
calibrated for the array AREA and BMC measurements.
1. Run 20 (medium) array scans by typing SCANSQ -PAP7SP60 -N20 -L6 (this will take
approximately 20 minutes, slightly longer on 50Hz machines).
2. When the scans have finished, return to the QDR software menu (type MAINMENU
<Enter>) and analyze the first scan using the default ROI. Compare each succeeding
scan to the first scan, using
compare
.
3. Once all of the scans have been analyzed, return to DOS (simultaneously press <Alt>
<F1>) and at the DOS prompt type FSCAL <Enter>.
4. Press "A" <Enter> to select the "
a: for ARRAY SPINE ACF/BCF
" option and to
calculate new ACF and BCF correction factors for the spine phantom used in the array
scan mode. The program will then display the
Array
spine phantom's serial number and
its appropriate Area and BMC values.
Do not change these values unless directed to do
so by an Hologic representative.
5. Press <Y> to verify the correct phantom serial number, area and BMC.
6. Press "+" to select the
20 (medium) array spine scans
from Step 1 above.
The program will then calculate new Array ACF and BCF values, and display them on
the screen along with the averages from the 20 scans, their upper and lower limits, and
their CV's.
Answer [
Y
]es/[
N
]o <Enter> to the query if you want to proceed/not proceed to update
the existing ACF and BCF values in the ARRC.TXT file with the new calculated
values. A screen with all the values will then be presented.
7. Make a note of the ACF and BCF values, then verify that ACFL is equal to ACF and
BCFL is equal to BCF. If they are not equal, edit the ACFL and BCFL fields to make
ACFL=ACF and BCFL=BCF.
8. Press <F10> (to have the second screen displayed). Verify that the ACFT is also equal
to ACF and the BCFT is equal to BCF. Again, if necessary, edit the ACFT and BCFT
fields to make ACFT=ACF and BCFT=BCF.
9. Press <F10> (to accept the values). The program will now verify that these values are
within specified limits and display those that are out of range. You will then be
returned to the FSCAL opening menu.
10. Press "W" <Enter> to select the "
w: final write to ARRC.TXT file
" option.
The program will then update the ARRC.TXT file and return to the FSCAL opening
menu.
The following messages appear:
Modified ARRC.TXT