الفهرس | Only 14 pages are availabe for public view |
Abstract Radiotherapy is one of the most important therapeutic modalities used to treat cancerous tumors. In radiation therapy, a cancer patient is given a dose of ionizing radiation determined by the radiation oncologist, and it is given to the patient by directing the radiation beams from outside the body (External Beam Radiotherapy “EBRT”) to an area previously determined by the radiation oncologist by drawing the outer bounders of the treatment volumes (tumors) through computed tomography (CT) images, which were previously taken to the patient as the first step of radiotherapy treatment process ”CT-Simulation”. During this scan, a comfortable position of the patient is selected, which helps in establishing the treatment plan, taking into account the capabilities of the radiotherapy treatment machine, the location of the treated area inside the body, and the healthy tissues surrounding it. The patient’s position during the treatment must be the same as the patient’s position during simulation process. The radiation fields are designed to treat the tumor(s) based on the size and shape of the tumor(s). The success of the radiation treatment depends on the accuracy of determining the target volumes being treated. There are many factors influence the accuracy of radiation therapy delivery. In addition to the experience and skills of the radiation oncologist to determine the target(s) to be treated, the quality of the acquired different image modalities which used to create the treatment plans play a role for the accuracy of determining the target volumes. As the image quality (resolution and contrast) is good, as the delineation of the target volumes be more accurate. The geometrical accuracy is one of the most important factors that affect the quality of radiotherapy. Radiotherapy is performed by placing the patient on the couch of the radiotherapy machine and moving the couch to adjust the center of rotation of the treatment device (isocenter). |