Background & objective: What damages 125Iodine (125I) seed implantation will do to normal tissue is an observation topic in clinic. This study was to investigate the impact of 125I seed implantation to the femoral arteries of rabbits.
Methods: A total of 30 healthy rabbits were divided into 3 groups. The femoral sheath in the hind leg at one side selected by random was opened and 10 125I seeds at 0.79-0.85 mCi were implanted near the femoral artery according to the treatment planning system (TPS) before operation. In control group, 10 seeds without radioactivity were implanted. After 2 weeks, 2 months and 4 months, the rabbits were killed, the vessel wall nearest to the seeds was taken out and its morphologic changes were observed by gross examination, light microscopy and electron microscopy.
Results: In gross observation, the vessel segments of the legs with 125I seed implantation had no apparent abnormality. Under light microscope, a few exfoliative endothelial cells were observed. Under electron microscope, exfoliation of endothelial cells, degeneration of endothelial cells and smooth muscle cells were observed. The ratios of degenerative vessel endothelial cells to all vessel endothelial cells were 60%-70% in 2-week group, 50% in 2-month group and 30% in 4-month group; the ratios of degenerative vessel smooth muscle cells to all vessel smooth muscle cells in the 3 groups were 50%, 30% and 10%.
Conclusion: 125I permanent implantation at 0.79-0.85 mCi mainly damages endothelial cells and smooth muscle cells of the normal vessels and this damnification is reversible.