On the measurement of positron emitters with Ge detectors

This paper discusses the problems related to the measurement of positron emitters with germanium detectors. Five positron emitters with important applications in nuclear medicine (22Na, 18F, 11C, 13N and 68Ga) have been studied. Measurements and Monte Carlo simulations have been used to determine the optimal conditions of measurement in gamma-ray spectrometry systems. The results obtained indicate that adding adequate absorbers, detection efficiencies are close to those of gamma emitters of similar energy measured in the same conditions, which allows a rapid calibration of a Ge-based spectrometry system. More accurate results are also presented using a detailed Monte Carlo simulation. Comparison to experimental data shows a good agreement.