الفهرس | Only 14 pages are availabe for public view |
Abstract Total-body irradiation (TBI) is widely used in radiotherapy prior bone marrow transplantation for treatment of leukemia and other malignancies. Two parallel opposed fields (anterior-posterior) at an extended source-to-midplane distance of 300cm from Cobalt-60 teletherapy unit (Theratron-780C) was chosen from different alternatives to be adapted for clinical service as a total body irradiator, at Mansoura University Hospitals, Clinical Oncology and Nuclear Medicine Department The dosimetric aspects was described for the proposed TBI technique aiming accurate dose delivery to the specified target volume and within the tolerance of normal tissues incorporated in the radiation field. A series of steps are done include measurement of machine data, set up technique, dose calculation, beam modification, and dose verification. The measured data of TMR and PDD for the largest field size available (132x132cm2) at 300cm SAD, and knowledge of attenuation coefficient values for different materials makes TBI is ready for medical service on the Cobalt-60 teletherapy machine. Dose verification is recommended using semiconductors detectors at entrance and exit points at different patient levels to verify the midline estimated doses using the developed algorithm. The quality assurance program and dose rate calibration are essential prior medical applications of TBI in patient treatment. |