Improved localization of a “hot spot” in the lungs for an array of four HPGe detectors—the simultaneous use of two gamma energies

Significant errors in the determination of radioactivity in lungs are caused by the usual assumption of homogeneous distribution, while actually the radioactive contamination can be in the form of a “hot spot”. Modern Lung Counter systems use several HPGe detectors, and the ratio of the different count rates of the detectors can be used to locate the “hot spot” and apply correction algorithms for activity calculation. rage error of only 9.5%, can be obtained when using this information for detection of a natural uranium point source in the lungs, when the analysis is based on either the 186 or the 92 keV peaks. In the present paper it is shown that the uncertainty can be further reduced to about 3.8%, if the two gamma energy peaks (186 and 92 keV) are analyzed simultaneously for the localization of the uranium point source.