Evaluation of Radiation Therapy Positioning System (RTPS) in Patients With Localized Prostate Cancer

The high precision of planned radiotherapy treatments requires accurate positioning of the prostate in order to ensure that the tightly conformed dose distribution does not miss the prostate and result in either significant tumor underdosage, an increased dose to the rectum or bladder, or both. Precise delivery has been addressed using a variety of pre-treatment localization systems. The most direct localization of the prostate involves the use of ultrasound, computed tomography (CT), or radiography of permanently implanted fiducial markers. In this study the safety and performance of a novel investigational tracking system will be evaluated. The Radiation Therapy Positioning System (RTPS) is a radioactive tracking system integrated into the radiotherapy set-up workflow. The System is composed of the Clinical Positioning System (CPS) and a radioactive soft tissue implanted fiducial (Blip), which is permanently implanted in the prostate. By tracking the implanted Blip, the CPS can monitor positional changes prior to and during the treatment. The accuracy of the RTPS localization will be compared to the CBCT in at least 5 radiation therapy sessions per patient.