3288 - Handheld Bladder Scanners Improve Treatment Efficiency and Safety during Radiation Therapy for Prostate Cancer

Purpose/Objective(s): A full bladder preparation is used in many centers and protocols for prostate / prostate bed radiation therapy. Typically, a cone-beam CT (CBCT) is used either daily or weekly during treatment to verify positioning of the target(s) and assess rectal and bladder filling. If there is insufficient bladder filling (or too much gas/stool in the rectum), then an intervention is needed and the patient will require one or more additional CBCTs that day. This creates significant workflow inefficiencies on the machine and increases radiation exposure and anxiety for the patients. We utilized a handheld bladder scanner to improve these issues.

Materials/Methods: Our standard department full bladder protocol involves emptying the bladder 60 minutes prior to CT simulation, verification simulation and treatments and then drinking 24 ounces of water. In addition, contours are exported to the linac for “Bladder” and “Bladder – Minimum Acceptable” for daily IGRT. For our prostate / prostate bed patients, we updated this to include bladder filling measurements with a handheld bladder scanner for the following: after emptying at the CT sim (to assess post-void residual / outlet obstruction issues); upon completion of CT sim (to compare ultrasound vs CT contours for bladder volume); and prior to VSim and all treatments (to ensure that minimum bladder filling is achieved). The bladder scanning process is done in a non-linac room, takes 3-5 minutes and is performed by a nurse assistant, nurse or radiation therapist. Daily CBCT is still used for target alignment and to assess rectal and bladder filling. Post-implementation of this protocol, 40 consecutive patients were analyzed and compared with 40 consecutive patients immediately prior to the update. Particular attention was paid to the number of CBCT’s needed, linac workflow efficiency and patient distress.

Results: The 40 pre-implementation patients underwent 985 total fractions and 1,176 treatment day CBCT’s. The 40 post-implementation patients underwent 1,012 total fractions and 1,055 CBCT’s. Given only 1 CBCT per day under ideal conditions, there were 191 “excess” scans pre-implementation and 43 “excess” scans post-implementation. This equates to a 78% reduction in excess CBCT’s.

Conclusion: Augmenting our full bladder protocol for prostate cancer with a handheld bladder scanner resulted in a significant decrease in excess CBCTs. This improved treatment schedule efficiency, reduced radiation exposure and decreased patient stress around achieving an adequately full bladder.