If these criteria are met, then determine the percent differ-
ence of the new dial value with respect to the nearest range
limit value (363 or 394), i.e., Dial Value Error (DVE). Add
this percent to the Change in Constancy Percent Error
(CCPE). If the sum of the errors is in the range of -2% to
+2%, then the new dial value should be used. If not, contact
Biodex Technical Support. The user may also want to con-
tact the radiopharmacy to determine if a calibration error
may have occurred.
The CCPE is the percent change from calibrator
installation of the constancy measurement, where CCPE =
"Today's" Constancy Percent Error – "Installation's"
Constancy Percent Error. The Constancy Percent Error is
the measurement error with respect to the decay corrected
source activity. A change down in the Atomlab Calibrator
constancy will cause a change up in the dial value required
to compensate the change in constancy, and visa-a versa.
Thus, the CCPE will have the opposite sign as the DVE, so
adding them should cancel to within 2%.
For example, a new dial value for Y-90 is found to be 400.
This falls outside the range and is +1.5% higher than 394.
The constancy measurement shows a -2.5% change since
the Dose Calibrator was installed. Their sum is (+1.5%) +
(-2.5%) = -1.0%, which within -2% and +2%. The dial value
of 400 should be used.
For all Dose Calibrator Models, the well liner must
be installed before making measurements. The well liner
provides attenuation for the Y-90 betas that would otherwise
enter the chamber and cause high readings.
ATOMLAB Dose Calibrator Operation Manual Appendix E
Biodex Medical Systems E-10 Release 2.0
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