Experimental study on radiation damage of 125I seeds implanted in canine gastric wall tissue

Objective: The objective of the study was to investigate the radiation damage to I-125 seeds implanted in canine gastric wall tissue. Materials and Methods: Eight beagles were randomly assigned to either the treatment or control group, with four beagles per group. For each beagle in the treatment group, six(125)I seeds were implanted in the gastric wall in two rows, spaced at 1.0 cm, with a seed activity of 0.5 mCi and a half-life of 60.2 d. For each beagle in the control group, six I-125 seeds were similarly implanted as a cold source. After implantation, the beagles were scanned by computed tomography (CT) (slice thickness: 2 mm), the region of interest was labeled along the seed boundaries, and postoperative doses were verified. One beagle per group was sacrificed at the 1, 2, 3, and 4 half-lives to be used as gross specimens for observing histological and ultrastructural changes using light microscopy and electron microscopy, respectively. Results: Beagles from the treatment group who had I-125 radioactive seeds implanted in their stomach walls had the most radiation damage after two half-lives, damage repair began after three half-lives, and the damage was stabilized and further repaired after four half-lives. In the control group, only mild inflammatory reactions were observed around the seeds. Conclusion: Appropriate and well-planned implantation of I-125 radioactive seeds in beagle stomach walls is safe and reliable.