FARNAZCUI/FA19-RPH-059/LHRDr.NaimaAminLHR TP 72462026-02-192021https://repository.cuilahore.edu.pk/handle/123456789/1963It has been long known that patients treated with ionizing radiation carry a risk of developing a second cancer in their lifetimes. Factors that contribute to the restate of cancer( or may be called second cancer) includes improved cancer survival rate by using high radiations as well as emerging treatment modalities.These modalities such as intensity-modulated radiation treatment(IMRT) and proton therapy. They can potentially elevate secondary exposures to healthy tissues distant from the target volume. In this study; a high energy radiations (6-15) MV are used in the treatment of cancer. External beam radiotherapy is used to deliver the radiations to the organ. Pelvic organ selected as a target volume. The pelvic organs include surrounding tissues/OARs such as bladder, rectum, small bowl, LT and RT femoral heads. Thus the purpose of this study is to analyze and calculate the effect of high energy photons on these surrounding tissues of pelvic. There are many clinical situations in which radiobiological considerations can be usefully applied and all clinicians should be aware of the potential benefits of developing a quantitative radiobiological approach to their practice. Thus Mathematical & biological model (LQM) is used as a tool to calculate the Biological Effective Dose (BED) and Biological Equivalent Dose (EQD2) with dose per fraction 2 for different Organs at Risk (OAR’s) nearer to the pelvic. Moreover the aim of this study is to provide an understanding of the principles and methods related to scattered doses in radiation therapy by summarizing a large collection of dosimetry and clinical studiesenDepartment of PhysicsFA19PhysicsHigh Energy PhotonsRadiosensitive AreasTreatment of CancerIREBRTLQMOARsBEDEQD2LT & RTPTVs.Dr. Naima AminThesis