This prospective study at MAMC evaluates the utility of a rigid pelvic external
immobilization compared to limited immobilization using a novel real-time localization system
of the prostate. The sample population will include patients referred to the radiation
oncology services of both facilities for definitive treatment of prostate cancer. The study
will enroll 20 subjects from MAMC and evaluate data on 860 radiation therapy fractions.
Subjects will have Beacon® Transponders implanted into the prostate to more precisely
localize the position of the organ during radiation therapy. They will be randomized to rigid
pelvic immobilization using a Vac-Lok® system or limited immobilization with a band around
the patient's feet. They will then undergo radiation therapy planning with standard planning
target margins. The Calypso® 4D Localization System will monitor, in real time, the position
of the prostate target and adjust radiation treatments as required to ensure accurate
treatment of the prostate gland. The time of, the number, and extent of adjustments will be
recorded for analysis.
Hypothesis: 1. When treating only the prostate, treatment with rigid pelvic immobilization is
not necessary when using real-time, state-of-the-art motion tracking of the prostate.