Constrained-beam inverse planning for intensity-modulated radiation therapy of prostate cancer patients with bilateral hip prostheses.

Hip prostheses present a technical challenge in the planning of curative external beam radiation treatment for patients with prostate cancer. Bilateral prostheses compel planners to compromise between target coverage and avoidance of beam entry through the prostheses. Inverse planning systems given objectives to avoid dose to prostheses are overly restricted from allowing exit dose to them. We report a novel inverse planning technique for intensity-modulated radiation therapy of patients with prostate cancer and bilateral hip prostheses, by constraining beam characteristics rather than dose in the inverse planning process.