Bremsstrahlung production by potassium-40 in muscle.
The bremsstrahlung spectrum produced when 1320 keV beta particles, emitted by the naturally occurring isotope 40K, are absorbed in muscle has been calculated. With reference to the external measurement of 239Pu in the lung using the 17 keV U L x-rays, a simple model was used to estimate the number of bremsstrahlung photons with energies between 12 and 25 keV that would emerge from the chest wall of a normal subject. This was calculated to be 3 min-1 for a detection area of 628 cm2, although internal bremsstrahlung may increase this to 4 min-1. The latter figure is a factor of approximately three lower than the counting rate observed when a pair of phoswich NaI detectors of the same total area are placed over an average subject. Possible reasons for this discrepancy are discussed.
D006801:Humans; D008168:Lung / Q000032:analysis; D009132:Muscles; D011005:Plutonium / Q000032:analysis; D011197:Potassium Radioisotopes; D011827:Radiation; D013909:Thorax
D011197:Potassium Radioisotopes; D011005:Plutonium