الفهرس | Only 14 pages are availabe for public view |
Abstract This study aims to reduce the set error during IMRT and reduce dose for healthy tissues and critical organs surrounding the tumor by using on line image guided technique. Intensity-modulated radiation therapy (IMRT) becomes popular because dose escalation to the target can be done while sparing adjacent normal tissues. IMRT tends to produce steep absorb dose gradients between the target volume and the OAR. This study was done to determine the error during RT on positioning displacement for patients treated for H&N cancer and prostate cancer. We tried to find the magnitude of daily setup errors to determine the set up error cases. The results can help physicians to determine the most suitable margin for H&N cases and prostate cases. Data from 40 patients (20 patient for H&N cases and 20 patient for prostate patient) calculated the Right/Left direction as X direction, Anterior/ Posterior direction as Y shift and Up/Down direction as Z shift. Average shift for all fractions calculated to be 0 .05 cm, 0.08 cm and - 0.02 cm as Rt/Lt, Ant./Post. And Up/Down shifts for head and neck (H&N) patients and Average shift for all fractions calculated to be 0.05 cm, -0.02cm and -0.39 cm as Rt/Lt, Ant./Post. And Up/Down shifts for prostate patients. To reduce setup errors in patients with H&N and prostate cancer receiving RT, the use of on-line image-guided radiotherapy is recommended to increase accuracy. |