Thesis (M.Sc.) - Cairo University - Faculty Of Science - Department Of Biophysics

In brachytherapy , remote afterloading (RAL) devices present a technological advance that offers several advantages over the manual afterloading technique ; improved radiation protection to the medical staff , reduced possibility of human error , and the increased ease of achieving optimized dose distributionsThe reliance upon these devices to execute the prescribed treatment demands a comprehensive quality assurance programThe present work describes a quality assurance program that has been developed and implemented for a low dose rate remote afterloading brachytherapy facilityFor the treatment unit tests fall into mechanical and functional , autoradiographic , radiation safety and sources dosimetryAll the tests were successful in 962percent out of all checks appliedAdherence to the ALARA principle has reduced the radiation exposures for brachytherapy staff using our (RAL) device ; this is checked by radiation survey measurementsDosimetry measurements using a well type chamber and the RAL Cs 137 sources were done ; showing reproducibility for the well chamber 051 percentCalibration of single Cs 137 sources resulted in variation between measured and given source strength in the source report ranged from 19 percent to 24percentWhile for the treatment planning system manual calculations for a single source were done regularly to check the dose rate calculated by the computer planning system showing discrepancy less than 1percent between the manual and computerized calculations of the dose rateThe inverse - square distance factor was checked for calculating dose at different points resulting in 088percent difference between computerized and manual calculationsEvaluation for 15 patients ̀treatment plan , treated from cancer of cervix , was done showing a very consistent dose to the bladder and rectum (organs at risk) , dose to bladder ranged from 18 percent to 82percent , while for the rectum ranged from 45 percent to 85percent from the prescribed dose

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