Radiation dosimetry of iodine-123 HEAT, an alpha-1 receptor imaging agent

Biologic distribution data in the rat were obtained for the alpha-1 adrenoceptor imaging agent (+/-) 2-beta-(iodo-4-hydroxyphenyl)ethylaminomethyl]tetralone (HEAT) labeled with 125I]. The major excretory routes were through the liver (67%) and the kidney (33%). Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads, and red bone marrow were calculated for the human using the physical decay data for 123I]. The critical organ was found to be the lower large intestine, receiving 1.1 rad per mCi of 123I]HEAT administered. The total-body dose was found to be 58 mrad per mCi.