Results
The results generated by the computer indicate the microcurie quantities
of the radionuclides that are present in/on the individual.
The computer an-
alysis technique used to resolve pnoto peaks from a Nai (T1) detecror is a
weighed least squares fitting technique.
This approach has been chosen over
manual spectrum stripping or photo peak regression analysis because the technique provides operator independent results, sufficient informacion to determine 1f a significane radionuclide has been missed and accurate results for
positively identified radionuclides when all nuclides present ia the sanple
are not present in the nuclear library.
There are limitations of this analysis software (Alpha T).
It is a
nuclide specific analysis technique with a limited nuclide library (12
This means that to properly analyze a spectrum, the operator aust
first know what are the possible components of the spectrum,
have calibration
standards for those nuclides, and then select the proper nuclides to be part
of the analysis package.
The system is also somewhat geometry sensitive.
No
geometric corrections are applied to the data other than those made by selec
tion of proper calibration phantom size.
Consequently, individuals who
significantly differ from the standard man, adolescent or juvenile phantom
used for system calibration may have their body burdens be in error by several
percent.
This error is not included in the counting error which is reported
with each result.
In addition, under routine operation, any positively identified nuclide
is assumed to have entered the body by the ingestion pathway.
For purpose of
dosimetry, the exposure is assumed to follow a constantly increasing or de~
creasing uptake scenario and the committed dose equivalent is computed based
on the measured body burden, retention functions and cumulated activity
7s,
nuclides).