Oral & Poster Presentation – Physics Abstracts Archive

UK & Ireland Prostate Brachytherapy Conference 2016

Abstract number 2

The effect of calcifications on prostate brachytherapy 

Lee J*; Welsh D*; Keough W*
*Edinburgh Cancer Centre, Western General Hospital 

AIMS/INTRODUCTION: Prostate calcifications are common in patients and even though there is no evidence to suggest a direct link to prostate cancer, they may have an effect on the treatment dose received. Treatment options available include HDR and LDR brachytherapy. Treatment plan dose distributions are usually calculated presuming a uniform water density. The aim of this project was to identify any differences in dose due to calcification by comparing HDR plans with and without a heterogeneity corrected dose calculation applied. 

MATERIALS/METHODS: 6 patients with prostate calcifications were identified. All of these patients had previously received LDR brachytherapy using I-125 seeds. An HDR template was applied and a plan was optimised using Brachyvision. Plans were then compared with and without the Acuros dose calculation. These plans were also exported to the 3DVH software for additional gamma analysis. 

RESULTS: Whole prostate and calcium wall (2mm around calcification) doses were analysed. The mean gamma pass rate (1%/1mm) was 99.0%. The whole prostate D95% was reduced by up to 1.4% and the calcium wall minimum dose was reduced by up to 1% compared with the uncorrected calculation. 

CONCLUSION: The results suggest that the presence of prostate calcifications is likely to have an insignificant impact on the dosimetric quality of HDR plans. Further work is recommended to investigate the effects on the lower energy LDR treatments.