Measurements of X-Ray Dose Delivered at Different Depths Applied on Water Phantom

Background Radiotherapy, is therapy using ionizing radiation in order to deliver an optimal dose of either particulate or electromagnetic radiation to a particular area of the body with minimal damage to normal tissues. The source of radiation may be outside the body of the patient (external beam irradiation) or it may be an isotope that has been implanted or instilled into abnormal tissue or a body cavity. Called also radiotherapy. The aim of work studies the relationship between the depth dose and the high photon x-ray energies (6MeV and 10MeV). Patients and methods in our work, we studied the dose distribution in water phantom given at different depths (zero-18) cm deep at1cm intervals treated with different field size (55-, 1010, 1515, 2020) cm2. Results show that the increasing the field size, the percentage of surface dose increases that this could be caused by an increase of the amount of scattering in the larger fields and on the other hand with increased energy, the percentage of surface dose will be reduced due to the reduced backscattered. Conclusion Increases field size increasing surface dose and this is attributed to the scatter radiation. Higher energy has higher depth dose at higher depth.