Prediction of in vivo background in phoswich lung count spectra
- Oak Ridge National Lab., TN (United States). Office of Radiation Protection
Phoswich scintillation counters are used to detect actinides deposited in the lungs. The resulting spectra, however, contain Compton background from the decay of [sup 40]K, which occurs naturally in the striated muscle tissue of the body. To determine the counts due to actinides in a lung count spectrum, the counts due to [sup 40]K scatter must first be subtracted out. The [sup 40]K background in the phoswich NaI(Tl) spectrum was predicted from an energy region of interest called the monitor region, which is above the [sup 238]Pu region and the [sup 241]Am region, where photopeaks from [sup 238]Pu and [sup 241]Am region, where photopeaks from [sup 238]Pu and [sup 241]Am occur. Empirical models were developed to predict the backgrounds in the [sup 238]Pu and [sup 241]Am regions by testing multiple linear and nonlinear regression models. The initial multiple regression models contain a monitor region variable as well as the variables gender, (weight/height)[sup [alpha]], and interaction terms. Data were collected from 64 male and 63 female subjects with no internal exposure. For the [sup 238]Pu region, the only significant predictor was found to be the monitor region. For the [sup 241]Am region, the monitor region was found to have the greatest effect on prediction, while gender was significantly only when weight/height was included in a model. Gender-specific models were thus developed. The empirical models for the [sup 241]Am region that contain weight/height were shown to have the best coefficients of determination (R[sup 2]) and the lowest mean squares for error (MSE).
- OSTI ID:
- 6278140
- Journal Information:
- Health Physics, Vol. 76:5; ISSN 0017-9078
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMERICIUM 241
FORECASTING
LUNGS
MATHEMATICAL MODELS
PLUTONIUM 234
POTASSIUM 40
RADIONUCLIDE KINETICS
REGRESSION ANALYSIS
SCINTILLATION COUNTING
SEX DEPENDENCE
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
AMERICIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
COUNTING TECHNIQUES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MATHEMATICS
NANOSEC LIVING RADIOISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANS
PLUTONIUM ISOTOPES
POTASSIUM ISOTOPES
RADIOISOTOPES
RESPIRATORY SYSTEM
SPONTANEOUS FISSION RADIOISOTOPES
STATISTICS
YEAR
YEARS LIVING RADIOISOTOPES
560161* - Radionuclide Effects
Kinetics
& Toxicology- Man