Grant: Collaborative Health Research Projects

Modern radiation therapy has advanced through the development of techniques to bettershape radiation dose to tumour volumes while minimizing adverse dose effects to surroundingnormal tissue. In brachytherapy (Greek: near therapy) radiation sources are placed into thetumour under robotic control. Placing a dose detector near the radiation source affects dosein adjacent regions. For this reason, dose delivery validation in brachytherapy is usuallybased on quality assurance of very simple geometries that are not as complex as thoseclinically encountered during patient treatments.A promising technique for dose measurement is gel dosimetry which is based on imagingspecial gel systems which change when irradiated. The changes can be imaged with varioustechniques available to our laboratory and provide the spatial distribution of the dose. Thegels mimic tissue and so the dose measured corresponds to the dose to a patient. As a result,dose measurement is more accurate and we can validate a planned delivery for a givenpatient before treatment starts.We propose to: i) test current gel formulations for their effectiveness and shortcomings inbrachytherapy dosimetry and create, characterize and test new formulations designedspecifically for brachytherapy applications; ii) develop standard protocols and phantomsspecific to brachytherapy dose delivery; and, iii) develop software to evaluate and comparegel-measured doses to measurements using conventional tools and to planned dose delivery.Testing of planned delivery is performed daily in other radiation therapy delivery with x-raymachines but is not yet available for brachytherapy. We will be the first to develop patientspecific dose delivery validation for brachytherapy.