Measurement uncertainties in whole body counting and radon progeny.
Measurement uncertainty is an important quality index in gamma spectrometry related to the level of bias and precision involved in the measuring procedure. Quality control measurements during the commissioning of a 16-input whole body counter showed substantial deviations between the experimentally determined precision and the theoretical estimation, indicating either equipment malfunction or lack of reproducibility of the experimental setup. In this study, the role of the magnitude and variability of airborne background radiation present in the counting room and the human body in the deterioration of the precision of counters employing NaI(Tl) detectors was investigated. Correction methods and actions based on case-specific background features were developed and applied. The experimental observations were benchmarked using a mathematical model of the counter. The efficacy of the developed methods was tested by measurements, and updated precision values were obtained. Quasi-equilibrium between the gamma-emitters Bi and Pb in the counting room and the human body is a prerequisite for accurate direct low-level radioactivity measurements in the human body.
*Medical Physics Department, School of Health Sciences, University of Ioannina, 45.110 Ioannina, Greece.
Stratos T
ST
Valakis
Stavroula
S
Pallada
John A
JA
Kalef-Ezra
D000328:Adult; D000368:Aged; D001417:Background Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D011188:Potassium / Q000032:analysis; D011886:Radon / Q000032:analysis*; D035501:Uncertainty; D014915:Whole-Body Counting
D011886:Radon; D011188:Potassium