Injury of ~(125)Ⅰ seeds implants to trachea and esophagus of rabbits / 中华胸心血管外科杂志

ABSTRACT

Objective To evaluate the impact of 1125 seeds para-tracheal braehytherapy on regional tissue injury in rab-bit models. Methods 42 rabbits were randomized into 7 groups. Group 1 to 6 belong to study groups (in which 1,4,5 and 6 belong to "dose gradient" subgroup, while 2,3 and 4 to "chronologic" subgroup) , while the last group acts as negative con-trol. The activity of seeds in study group were 0.3 mCi in group 1, 0.5 mCi in group 2 to 5, 0.7 mCi in group 5, and 0.9mCi in group 6. False seeds (0 mCi) were used for the negative control. 4 seeds with equal dosage were implanted between trachea and esophagus in each rabbit under general anesthesia. Seeds arrangement was made according to Paris principle. For the tissue injury evaluation, group 2 was sacrificed by the end of first month post-operatively, group 3 at the end of the second month, and group 4 end of the third month. The rest of rabbits were also sacrificed at the end of the third month. Pieces of adjacent e-sophagus and trachea were sampled from each rabbit. Tissue injury features such as inflammation, edema, congestion or fibrosis as evaluated histologically. Results All rabbits were healthy during study period except 5. Histological analysis revealed that trachea samples from all groups had lymphocytas and plasma cells infiltration as signs of chronic inflammation, hut fibrosis was nut clearly visible. There were no differences between study and control groups with respect to inflammation, edema and con-gestion scores. But in groups which received the highest doses of radiation or sacrificed at 60 d showed more eosinophil infiltra-tion and epithelum degeneration, and statistical significance was reached between these groups and control. Esophageal samples had less histological changes compared with trachea. Conclusion Para-tracheal implantation of ~(125)Ⅰ seeds with therapeutic or higher dosage only induce minor and reversible damage to the regional tissue. This implies that ~(125)Ⅰ implants adjacent to trachea or esophagus are clinically safe.