CT Scans in Guiding the Treatment of Patients With Prostate Cancer Who Are Undergoing Radiation Therapy

OBJECTIVES:

Compare the accuracy of radiotherapy delivery using multiple CT scans to guide patient positioning vs the standard portal image guided procedure in patients with prostate cancer undergoing external beam radiotherapy.
Determine the reduction in the proportion of patients with large target positioning errors using the CT-guided procedure.
Determine organ motion and setup errors over the course of radiotherapy in order to develop efficient clinical intervention strategies in these patients.

OUTLINE: Patients undergo radiotherapy over 9 weeks. Patients undergo a CT scan immediately prior to receiving radiotherapy on treatment days 3-8 and then weekly thereafter. On 3 different days, patients also undergo CT scan immediately after radiotherapy. If the CT scans indicate a correction that exceeds the action level currently in effect, then beginning with the next treatment, the patient's position with respect to the radiation field is adjusted.

PROJECTED ACCRUAL: A total of 25 patients will be accrued for this study within 2 years.