[Experimental study on 123I-IMP kinetics in irradiated lung of rabbit]

Radiation-induced alteration of intra-pulmonary kinetics of 123I-IMP was investigated in 11 rabbits received a 50 Gy dose of radiation to the hemithorax. In all of these rabbits examined during 3-17 weeks following the irradiation, an abnormal accumulation was seen in the irradiated lung on the delayed image obtained 60 minutes after the injection of 123I-IMP. The time-activity curves in the irradiated lung following the injection had shallower downslopes of both the initial fast phase and the following slow phase than those of non-irradiated lung, and finally 123I-IMP uptake of the irradiated lung exceeded that of the normal lung. Chest radiographies all of 11 rabbits showed no abnormal shadow and histological studies in 6 of them revealed a relatively slight change or injury of the irradiated lung during 3-17 weeks. These results indicate that this agent may be useful for detecting and assessing relatively early and slight lung injury induced by irradiation.