B-
1
APPENDIX B
CROSS-CALIBRATION
Cross-Calibrating a QDR FAN-BEAM SYSTEM to
another QDR FAN-BEAM SYSTEM
This procedure describes how to cross-calibrate a QDR fan-beam system to another QDR fan-
beam system.
It is assumed that this procedure is used to cross-calibrate a new (just installed) QDR system to
an existing QDR system. For clarity, the new (just installed) QDR system is referred to as “NEW
QDR” and the existing QDR system is referred to as “ORIGINAL QDR”.
The spine phantom shipped with the NEW QDR is referred to as the "NEW PHANTOM" and the
phantom shipped with the ORIGINAL QDR is referred to as the "ORIGINAL PHANTOM."
The ORIGINAL PHANTOM is used for the cross-calibration procedure. The NEW QDR is
calibrated to produce the same values as the ORIGINAL QDR on the ORIGINAL PHANTOM.
In cases where the customer intends to keep the ORIGINAL QDR system and operate it
alongside the NEW QDR system, the ORIGINAL PHANTOM should be used for daily QC on
both the ORIGINAL QDR and the NEW QDR. Using the same phantom on both machines
simplifies the interpretation of the QC results from the two systems because you don’t have to
correct for differences between the two phantoms.
In some cases it is not practical to use the ORIGINAL PHANTOM for daily QC on both systems.
For example, if the two systems are not in the same room, it may be necessary to use the phantom
supplied with each QDR instrument for daily QC on that instrument. If the ORIGINAL
PHANTOM cannot be used for daily QC on both machines, the NEW PHANTOM must be
scanned on the QDR and relabeled after the NEW QDR has been cross-calibrated to the
ORIGINAL QDR using the ORIGINAL PHANTOM (see Step 4 below).
If two or more spine phantoms are kept on site, the spine phantoms should never be switched
between QDR instruments when performing daily QC measurements. Doing so defeats the
purpose of the quality control program. The operator should be instructed to always use the same
spine phantom for a given QDR system.
If the ORIGINAL QDR is being de-installed, the ORIGINAL PHANTOM should be kept on site
and used to perform daily QC on the NEW QDR. The NEW PHANTOM should be shipped back
to the factory along with the de-installed ORIGINAL QDR.
Definition Summary
FAN-BEAM SYSTEM QDR 2000, 2000
plus
, 4500.
NON-FAN-BEAM SYSTEM QDR 1000, 1000
plus
, 1000/W, 1500, 4000.
QDR For this procedure only, a QDR means any Hologic fan-beam
system.
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