Poster Presentation – Abstracts Archive

UK & Ireland Prostate Brachytherapy Conference 2017

Abstract number 15

The Grandfather Effect- personalizing radiation safety precautions following prostate implantation with I-125 Seeds

O’Neill M*
*Beaumont Hospital, Dublin

AIMS/INTRODUCTION: After implantation of I-125 seeds into the prostate gland, patients can emit low levels of radiation. For the safety of the public and the patient’s family, patients are advised to restrict their contact with others, particularly small children. These radiation protection guidelines last for 1 year. Clinicians report that patients may refuse prostate brachytherapy due to these guidelines. The aim of this work is to develop patient specifi c radiation protection guidelines.

MATERIALS/METHODS: Surface dose rate measurements of 95 I-125 seeds in a full-scatter phantom were taken. An algorithm was then developed to model the attenuation of the radiation emitted from the seeds through the phantom material. Once validated for the phantom material the algorithm was then modifi ed to refl ect attenuation through the patient anatomy. Estimated dose rates from the algorithm were compared with dose rates measured at 0cm(surface) and 30cm from these patients. From these doserates, the exposure times to meet 1mSv were calculated. A programme was created to estimate patient specifi c guidelines.

RESULTS: Estimated and measured doserates were found to agree within uncertainties. Measured surface mean & 30cm mean (15.23uSv+/-7.77uSv & 2.14uSv+/-1.20uSv) compare with estimated surface mean & 30cm mean (15.03uSv+/-7.59uSv & 2.28uSv+/-1.21uSv). Dose rates were found to vary signifi cantly. 75% of patients couldn’t induce 1mSv from 30cm, time for remaining 25% ranged from 102 days to 235 days. It was found that the standard guidelines were signifi cantly overly restrictive for most patients.

CONCLUSION: The study shows that standard guidelines are overly restrictive. The algorithm developed here is capable of accurately estimating dose rates from prostate brachytherapy patients, within respective uncertainties. The programme developed can be used clinically to better advise patients on the radiation precautions that are specifi c to them. The incorporation of this programme will help healthcare professionals provide patient specifi c care to individuals undergoing I-125 prostate brachytherapy treatment .