Study of Radiation Doses Distribution

Radiation therapy is the use of certain type of energy (originated from ionizing radiation) to kill cancer cells and shrink tumors. According to the recommendations of international institutes of radioprotection, an increasing attention is being paid to tThe present study is planned to measure and assess the radiation doses received by the target organ and the surrounding healthy sensitive organs in external radiation treatment. This will make it possible to produce almost any desired dose to the tumor voGreat interest was directed towards the breast and bladder because these two organs are the most liable to be affected by cancer in women and men, respectively in Egypt. Before calculation of the dose distribution in the mathematical model, it is necessarIn case of breast radiotherapy, radiation dose distribution in the breast and the surrounding organs was measured using human-phantom. During experimental practice, The Alderson Rando Phantom (ARP) was irradiated following the experimental set up in an acA Co60 source is used in this experiment as a source of gamma rays with average energy 1.25 MeV. The Co60 source is in the form of a cylinder of diameter 2.0 cm and 2.0 cm length with its circular end facing the phantom. The daily fraction (df) dose was 2All the experimental setup information was fed to the MCNP-4b code to calculate the dose distributions at the selected pointes. The depth dose distribution was performed also. Both measured and calculated data were compared.From the comparison between the measured and the calculated results, it was found that the difference between the measured (M) and calculated (C) doses relative to the measured [(M-C)/M] ranged from -0.376 up to 0.269 The comparison showed also that the cOnce the theoretical measurements of the radiation doses was validated by comparison with measured one, the effect of some factors such as shielding, obesity and breasts size on dose distribution can be studied. This will be of great importance in obtainiOn the other hand, the dose distribution in different organs during a case of actual bladder radiotherapy was measured using same human-phantom. During experimental practice, The ARP was irradiated following the experimental set up in an actual bladder ra6 MeV X- ray beam is used in this experiment. The daily fraction (df) dose was 200 cGy during the treatment session. The source to surface skin distance (SSD) is 100 cm. All the experimental information was fed to the MCNP-4B code to calculate the dose diIn order to obtain the optimum conditions for bladder radiotherapy, the impact of filling of the urinary bladder on dose distribution was studied. The volume of bladder model was doubled and filled with water then the doses distribution was calculated at The comparison indicates that there is good agreement between the measured and calculated doses in the target organ (bladder) and the surrounding healthy organs. Comparison between the calculated and the measured results for a single beam only also showedThe comparison between measured and calculated depth dose distribution for 6 MeV X-ray was carried out. The depth dose distributions for the anterior, posterior, right, and left fields were performed, and the result gives a clear description for the radiaIn conclusion, The MCNP model used in the present study shows accurate results and is proven to be suitable for applications in radiation protection field. It can be also extended to study the dose assessment in the human body in case of external exposure