Dosimetric verification of point doses for I-125 implants designed by different manufacturers in prostate brachytherapy.

BACKGROUND

The purpose of this study is to determine the effect of the type of I-125 radioactive source on dose distribution in the planning process of ultra-low dose rate (uLDR) prostate brachytherapy.

MATERIAL AND METHODS

7 patients who had undergone brachytherapy in our center were included in the study. Dose in five geometrical points were analyzed for 12 types of implants that are available on the market. The plans were originally calculated for S17plus implant model (Eckert & Ziegler Medical). Point dose calculations were performed using RadCalc (LAP) software.

RESULTS

The differences in doses for individual points were significant. The largest differences were observed at the point located in the center of the patients' urethra and between BestMedical 2301 (highest doses for each point) and IsoStar (lowest doses) implants.

CONCLUSIONS

The choice of implant manufacturer strongly influences what dose distribution will be obtained for the prostate. It is possible to obtain satisfactory plans that meet the dosimetric criteria for each type of implant, but the positioning of each source will vary significantly.