Evaluation of the dose delivered through the treatment procedures in radiotherapy

Abstract

''This work concentrated on the study of the uncertainty m the dose delivery for the patients who treated by radiation from cancer diseases. The radiation doses for the patients treated by radiotherapy are similar to the medicine (Drags) for patients treated by chemotherapy, where the dose is determined accurately:••Therefore, the study of the accuracy of dose delivery and the setup for radiotherapy is very important work. In this study, we investigated the sources of uncertainties in radiotherapy procedures and recorded the values of uncertainties, which compared with the international recommendations. The first step in radiotherapy procedures is the • imaging process ofthepatient. We study the relation between the CT-number of computed tomography (CT) and the electron density for the scanned body.

excellent agreement between the CT-number and the electron density was achieved. The second step is the treatment planning system (TPS) stage. In this step we investigate the ability of the system to recognize on the CT-number and its accuracy for deter:tnining the target volumes from CT-cuts. The results indicate that TPS is very accurate for dose calculation and distribution. The setup precision of setup machines was investigated using the simulator. The correspondence between the TPS and the simulator is obvious. The last and most important step is the investigation of the dose delivered to the desired place. The treatment machine was calibrated before we measured the delivered dose because the determination of the dose is very accurate. The phantom was adjusted on the couch of machine. The setup data was applied where the isocenter of machine deposit in the ceneter of desired place. The inadiated was started and the entered dose measured using detector inserts inside the phantom. The measured dose'Tor all beams was recorded and conected using the calibration factor. By comparing the measured dose with the calculated dose from TPS, there is excellent agreement and more accurate for the dose delivered to the target.