Calypso System

In cancer therapy, precision is everything. Killing cancer cells while sparing healthy tissue requires a delicate balancing act, one that can be particularly challenging in external-beam radiation therapy. Off-target radiation delivered to healthy tissue can result in unpleasant side effects such as bowel or bladder incontinence or sexual dysfunction. The human body is a dynamic environment, constantly in motion even at rest. No matter how still a patient attempts to remain during radiation treatment, body processes create continuous motion, making it difficult to keep radiation focused with pinpoint accuracy throughout treatment. This is especially true in treating prostate cancer; due to its location near the bowel and bladder, the prostate’s motion is the most unpredictable and variable of all.

This movement may be due to a cough, normal digestion, or simply breathing, but as a result, the tumor also moves in and out of the path of the radiation beam. In traditional treatment, to compensate for the exposure of healthy tissue caused by movement, a less powerful radiation beam must be used. In addition, movement of the tumor out of the beam further reduces the radiation delivered, potentially changing the effectiveness of the therapy. Historically, higher doses delivered to cancer cells lead to better outcomes. The goal is to get the most radiation to cancer cells, while shielding healthy ones.

The Martin O’Neil Cancer Center offers treatment using the Calypso^® System, known as GPS for the Body^®. Calypso reduces the tracking challenge with continuous, real-time tracking of the target area, the only FDA-cleared real-time tracking technology. Developed by Seattle-based Calypso Medical Technologies, Inc., the system uses harmless radiofrequency signals to continuously monitor the location of the tumor in relation to the radiation beam. The key to the technology is three tiny electromagnetic Beacon^® transponders – smaller than grains of rice – implanted in the prostate in a quick outpatient procedure. The Calypso System locks onto the signal during setup at each treatment session, verifies the information against the patient plan, and continuously tracks the exact location of the tumor. Visual and auditory alerts tell the therapist if the tumor moves outside the radiation beam, allowing the therapist to stop the beam, make any necessary adjustments to the patient's position, and resume treatment. The result is better outcomes, with fewer side effects.