Prostate cancer is the most common form of cancer in men and the second leading cause of death for men in the United States. The American Cancer Society estimates that approximately 1 in 6 men will be diagnosed with prostate cancer in his lifetime, but only 1 in 35 will die from it. Advances in the detection and treatment of prostate cancer have led to increased rates of survival for patients. Although clinical evidence strongly indicates that treatment practices for prostate cancer are effective, a serious challenge remains in treating patients with radiation therapy—the issue of prostate movement. Studies show that the prostate can move from day-to-day within the patient’s body, depending on how full the bladder is and whether or not there is stool in rectum. Even deep breathing, coughing or laughing can change the location of the prostate.

The issue of prostate movement is still largely unaccounted for in current planning and treatment protocols. Given the extended duration of a treatment course for radiation, a practical solution to this problem is to visualize the tumor cavity on a daily basis prior to delivering radiation. Until recently, there were very few options for visualizing the actual prostate in order to ensure precise delivery for radiation. Daily x-rays or CT scans can help to visualize the target, but they also have the potential to deliver an unnecessarily high dose of radiation to healthy tissue.

Resonant Medical, of Montreal, Canada, developed a way to visualize the prostate each day without exposing the patient to unnecessary radiation. Radiation oncologists are using image-guided radiation therapy (IGRT) which utilizes 3D ultrasound to visualize the location of the prostate during radiation treatment planning and delivery. With the FDA-cleared Clarity System, radiation therapists can take a “real-time” image of the prostate at the planning stage and then daily prior to each consecutive radiation treatment. IGRT using 3D ultrasound provides a method of monitoring the prostate based on daily images of the patient’s actual anatomy—rather than an estimation of the location of the prostate. This precision could enable physicians to reduce the field of radiation they need to deliver, which is always preferable if clinically justified. Clarity uses the same gentle, non-invasive ultrasound technology that male patients may associate with providing images of their unborn children.

In clinical studies, the Clarity system has been found to be very useful in conjunction with CT for treatment planning and to provide daily treatment verification. The benefits of 3D ultrasound for planning can also be realized in the delivery of radiation treatment, where no current standard exists for visualizing the cavity on a daily basis. Clarity also gives patients peace of mind that their radiation is being delivered directly to the area where it is needed most while minimizing exposure to healthy tissue and reducing the risk of potential side effects.