Oral and Poster Presentation – Physics Abstracts Archive

UK & Ireland Prostate Brachytherapy Conference 2017

Abstract number 8

Optical ﬁbre luminescence sensor for real-time LDR Brachytherapy dosimetry

Woulfe P*; O’Keeffe S**; Sullivan FJ†
*The Galway Clinic; **University of Limerick †The Galway Clinic & The Prostate Cancer Institute

AIMS/INTRODUCTION: An optical ﬁ bre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical ﬁ bre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical ﬁ bre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 400µm of a 500µm plastic optical ﬁ bre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the ﬁ bre, propagating along the optical ﬁ bre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

MATERIALS/METHODS: The optical ﬁ bre sensor was ﬁ xed within a Novel Prostate Phantom to allow for comparison of results with the treatment planning system Variseed. The brachytherapy seeds were inserted into the Phantom for a ﬁ xed period of time and the response of the sensor monitored. The sensor was initially tested for its response to 6.3mCi of Iodine-125.

RESULTS: The sensor was further evaluated for its response to different levels of radiation to determine its suitability for brachytherapy applications.

CONCLUSIONS: Having now identiﬁ ed the most suitable size PMMA plastic optical ﬁ bre for this application (400µm), further work will investigate the sensor to a range of different activities for Iodine-125 and will be investigated for its distal response and angular behaviour at these different activities.