The Intensity modulated radiation therapy (IMRT) treatment program is optimized to deliver a high dose of radiation to the tumor while sparing the surrounding healthy tissues, to decrease the damage. In order to achieve this result a linear accelerator shapes the beam of radiation. During the course of treatment a technique called Image Guided Radiotherapy (IGRT) is used to take daily portal images of the patient to verify and adjust the patient to verify and adjust the patient before each treatment. Wake Forest University Baptist Medical Center uses implanted gold markers to position the prostate in the daily images and to shift and rotate the patient such that the target volume is aligned with the isocenter.

The purpose of this study is to examine the effect of verification imaging on the treatment plan. The radiation fields used for daily portal images taken from prostate patients are open and relatively large in size. IMRT treatment plans do not take into account the effects of imaging, though this effect can be incorporated. The large, open image fields(range 10-20) may degrade the intended high dose gradients of the treatment fields. This research would help to quantify the radiation dose from images taken during the course of IMRT radiation therapy of prostate. Our knowledge gained by scholarly literature search, shows that there have not been any published report regarding the effects of imaging and changes caused on the planned dose distribution regarding IMRT.