EFFECT OF HIP PROSTHESIS TO THE DOSE DISTRIBUTION IN MEGA-VOLTAGE RADIOTHERAPY

Radiotherapy planning for patients with hip prosthesis who have pelvic area irradiation indication is a frequently met problem for physicists and physicians. A research using different sizes and shapes of titanium and stainless steel hip prosthesis models with Cobalt-60 and 8 MV photon beams has been done in our center to find maximum diminishing and diminishing rates. In this research confusions caused by hip prosthesis have been found to be significant. 70% maximum diminishing has been found in the 58 mm diameter hallow stainless steal prosthesis. This maximum diminishing has taken place in a small area beneath the prosthesis. The mean diminishing of the prosthesis has changed between 5.6% and 31.6% due to the differences in prosthesis and energies worked with. We have compared our measurement results with the results of our treatment planning systems for these materials with high electron density. Maximum diminishing and diminishing, rate results will provide sufficient knowledge to the clinician for choosing a treatment plan.