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M. L. Schaffner*, A. Horabin, K. Thaggard,
G. Glesinger, A. M. Zimmer; PET Section, Northern Shared Medical
Services, Madison, WI; Department of Nuclear Medicine, Northwestern
Memorial Hospital, Chicago, IL. (651514)
Monday, June 21, 2004, 8:45 AM, Technologist
Paper Session: Technologist Abstract Track - Radiopharmaceutical/Chemistry
(8:00 AM-9:30 AM) 201 B
Objectives: F-18
FDG unit doses, from different radiopharmaceutical vendors, are
routinely provided to ten mobile PET and PET/CT coaches. Dose calibrator
assay of received F-18 FDG doses were significantly different than
assays provided by vendors. Assay differences in F-18 FDG unit doses
and possible reasons for these differences were evaluated.
Methods: Capintec
dose calibrators (Capintec Inc) are used by all vendors evaluated
in this study. Biodex Atomlab 100 dose calibrators (Biodex Nuclear)
are used on all mobile coaches. Each coach has a National Institute
of Standards and Technology (NIST) traceable positron-emitting standard
(Ge-68/Ga-68) which is used to evaluate dose calibrator accuracy
on all coaches and also on a Capintec CRC-15 dose calibrator. Differences
in measured F-18 FDG unit doses supplied by various vendors were
measured for a 2 to 4 week time period.
Results: Dose calibrator
assays of F-18 FDG doses were 19.6% ± 5.5 % (mean and standard
deviation, n=16) and 7.3% ± 2.8% (mean and standard deviation,
n=30) lower than assays provided by two different vendors. Biodex
Atomlab 100 dose calibrator accuracy assessment with a NIST traceable
Ge-68/Ga-68 standard deviated by -1.4% ± 0.5% (mean and standard
deviation, n=7) of specified standard activity. With the same NIST
traceable positron-emitting standard, the deviation in a Capintec
CRC-15 dose calibrator was 5.2% of specified standard activity,
resulting in a calibrated difference of 6.6% between vendor and
end user assayed dose.
Conclusions: Significant
differences in F-18 FDG assayed doses provided by radiopharmaceutical
vendors were demonstrated; differences in assayed doses from one
vendor were due to specific type of dose calibrator used. Recalibration
of F-18 dial settings in commercial dose calibrators should be considered.
Keywords: Dose
calibrator | Fluorine-18-fluorodeoxyglucose (FDG) | Assay
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