An implantable in-vivo dosimeter for the measurement of delivered dose to patient during radiation therapy

International Conference on Medical Physics

August 03-05, 2015 Birmingham, UK

Anas Ismail

Posters-Accepted Abstracts: J Nucl Med Radiat Ther

Abstract :

The dose control and related safety of radiotherapy treatments remain a major issue for complex treatments or new procedures. One solution to deal with this technical challenge is the direct and real-time dosimetric monitoring using implantable probes. However, no commercially available implantable in vivo dosimetry nowadays can meet requirements for real-time precise measurements. Implantable MOSFETs cleared by the US FDA for some breast and prostate therapies have drawbacks such as non real-time response, large size, non-extractable and a 4% associated risk of migration. Other in vivo dosimeters such as those based on prompt radioluminescence (RL) of Al2O3:C, also have serious precision limitations due to requirements for non-linear response calibration and periodic optical stimulation to release charge trapped in the material. Recently, a real-time dosimeter with an implantable optical fiber probe has been proposed. The probe incorporates a small GaN (Gallium Nitride) bulk as scintillator to emit prompt radioluminescence (RL) signal under irradiation. This material has a high light yield with linear dosimetric response over a wide dose range. Its RL response has no dose rate dependence. The percentage depth dose (PDD) results were in excellent agreement with those measured with reference to ionization chambers. Its thermal stability and its radiation hardness are also suitable for radiotherapy applications. Moreover, it has interesting properties in terms of biocompatibility and chemical stability. GaN dosimetric system appears as a promising tool for the independent dose verification of complex treatments.