jeccribed.
The chair zeometry detects radioactive material located between the
neck and the knee.
The total system efficiencies are the same for the chair and
ded geometries.
3.
Quality Control
The quality control (QC) program consisted of a cross comparison
of the radionuclide amounts estimated to be in the phantom volume versus NBS calLoration standards.
Agreement between the two activity concentrations is within
plus or minus 5% for all radionuclides.
Other quality control mechanisms
employed were repetitive counting of secondary point source standards, multiple
counts of 3rookhaven personnel, repetitive counting of the Marshallese (blind
duplicates) and an intercomparison study.
Two point sources were used in the QC program.
Initially 1376,
source, which has been used by the BNL medical surveys in previous years, was
used to monitor potential changes in system resolution and efficiency as fune-
tion of time.
In subsequent years, a 1370, + 8000 point source, was used for
zero, gain, resolution and efficiency determination.
Replicate counting of Marshallese was conducted on 5% of the
subjects.
Results indicate that the data obtained from the field whole body
counting system is reproducible to within plus or minus 6%.
error is due to variable subject position.
Almost all of this
When subjects remain stationary, the
difference between sequential results is plus or minus 1%.
An intercomparison of whole body counting systems was conducted between the field system and the whole body counter operated by $. Cohn for the
Brookhaven Medical Department.
Persons used in the study included 13
Marshallese with measurable 13765 body burdens plus several Brookhaven employees
with current whole body counting records at the Medical Department.
The results
‘
e