Source of Support: None, Conflict of Interest: None
The goal of the radiation therapy can be achieved if the prescribed dose is delivered to the defined target volume accurately with acceptable uncertainty. The aim of the present study was to assess the accuracy of dose delivery in brachytherapy, where measured dose was to be compared with treatment planning system (TPS) calculated dose under the comprehensive quality assurance. The therapy level ionization chamber of 0.1cc volume was placed inside the surface mould (wax medium) designed for the treatment of carcinoma of skin. The delivered dose was measured during the treatment for all fractions. The theoretical study on non-uniformity correction factors for 0.1 cc chamber and experimental study on relative transmission factor from wax to water medium that influence the measured dose were performed. The variation in TPS-calculated dose at the reference points inside chamber sensitive volume was observed to be 17.5% of the mean dose. The relative transmission factor from wax to water medium was 0.9934 per cm. The difference between the measured dose and TPS-calculated dose was 2.52%. The uncertainty in dose measurement was estimated to be + 3.8%. The accuracy of dose delivery was found well within the prescribed limit.