Experimental study on radiation damage of125I seeds implanted in canine gastric wall tissue

Objective: The objective of the study was to investigate the radiation damage to125 I 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, six125 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 125 I 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 had125 I 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 of125 I radioactive seeds in beagle stomach walls is safe and reliable