Maintaining consistent bladder filling during external beam radiotherapy for prostate cancer.

Radiation therapy for patients with prostate cancer is preferably provided with a full urinary bladder. Full bladder can potentially move the small intestine out of the radiation treatment regions, and results in decreased small bowel radiation dose and gastrointestinal toxicity. Maintaining consistent bladder filling during computerized tomography simulation scan used for treatment planning and at daily radiation treatments is challenging. Here we present an in-development urinary catheter with a floating balloon that drains the bladder only when urine reaches to a prespecified level, and review current methods used in clinic to ensure consistent bladder filling. These includes bladder filling protocols, ultrasound scanning and biofeedback techniques.