[Effect on dose owing to source displacement in coronary endovascular brachytherapy].

OBJECTIVE: To investigate the effect on the dose distribution of source position displacement with the target region margin in catheter-based 192Ir line source endovascular brachytherapy. METHOD: Dose rate distribution along longitudinal axes was estimated by the formula recommended by AAPM No.60 and No. 43. RESULTS: In the two cases of source displacement (1.1 and 5 mm) doses of target region margin was decreased dramatically (at most 53.9% and 565.8% respectively) were compared to that of no source displacement, and the affected range was 6 mm and 9 mm respectively. CONCLUSION: Source displacement will lead to the decrease of dose in target region margin.