With a variety of cross section of the thickness of the computerized tomography received with critical organ and the target volume effect of radiotherapy plans

Three-dimensional conformal radiotherapy technique, depending on the patient's disease stage of the planned target volume (PTV) and organs are determined by taking into consideration the internal movements of the intact tissue irradiation with margin of safety to minimize the patient's quality of life affecting the results can be obtained.The first phase of the treatment of cancer patients has an important place in the simulation of radiotherapy equipment. Three-dimensional conformal radiation therapy technique used in computed tomography images taken with the patient's planned area and entered through the volumes of these images is provided with the patient's treatment. Dose distributions obtained with this treatment, the planned target volume isodose surfaces creates the best. This three-dimensional conformal radiotherapy technique izodozlar target, depending on the patient's disease stage of the planned target volume (PTV) and organs are determined by taking into consideration the internal movements of the intact tissue irradiation with margin of safety to minimize the patient's quality of life affecting the results can be achieved. The images were obtained for the various thicknesses.This study Education and Research Hospital, Samsun, computerized images of 9 bladder cancer, gastric cancer, 8 of computerized images, 10 of lung cancer re-kesitlenerek computerized images of the patient 2 mm, 5 mm, 6 mm, 8 mm and 10 mm sections were obtained. Each of these sections, as well as separate volumes by entering the target volume and critical organs received doses compared. Isodose curve was created by choosing to hold the best planning. Computed tomography images obtained with slice thickness varied by changing the volumes and volumes to how much how much dose was taken.Key Words : Computed Tomography, Radiotherapy, Bladder Cancer, Lung cancer, Stomach Cancer