Object: Using computer to calculate average energy lost by photons at every points in each body, in order to determine the dose distribution of photon radiation in the water phantom.

One of the major disadvantages of MRI is its image distortion, which affects the accuracy of the localization of SRT and the veracity of the dose distribution.

For obtaining the distribution of absorbed dose in tumor and surrounding tissues after implant of seeds, the software, Interstitial Treatment Planning System of seeds (ITPSS 1.0) was programmed.