RT Journal Article SR Electronic T1 Can a Detector in Live-Time Mode Give a True Count Rate? JF Journal of Nuclear Medicine Technology JO J. Nucl. Med. Technol. FD Society of Nuclear Medicine SP 38 OP 39 VO 18 IS 1 A1 Chen, Ching Y. A1 Chu, Robert Y. L. YR 1990 UL http://tech.snmjournals.org/content/18/1/38.abstract AB Count rate in the live-time mode of a nuclear detection system should ideally be directly proportional to the disintegration rate of the sample assayed. We examine the linearity of the relationship by measuring the deadtimes using two different detection systems. For the sodium iodide (NaI) crystal detector system, iodine-125 (125I) was used with the two-source method and the results were confirmed by the decaying-source method in which indium-113m (113mIn) was employed. For the cadmium telluride (CdTe) semiconductor detector system, the decaying-source method and 113mIn were used. In both systems, we found that nonlinearity at a high count rate could be significant.