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Treatment Options > Radiation Oncology > Treatment
Calypso® 4D Localization System
Nathan Jones, DO and Neha Vapiwala, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 14, 2008
The latest radiation therapy techniques for cancer treatment allow more precision than ever before. This can translate into fewer side effects and potentially better tumor control as the radiation beam is focused to treat the cancer while avoiding the normal organs as much as possible. Although radiation treatment is intended to be delivered with pinpoint precision, normal organ and patient motion, along with uncertainty regarding the exact location of the target, can all diminish the accuracy of the treatments. It has been clearly shown that normal organs naturally move during and between treatments. This is obvious in organs like the lungs that clearly move with breathing, but it also occurs in less obvious places, such as the prostate. This movement is impossible to predict exactly, so efforts are underway to monitor these movements and account for them, such that the radiation treatment is delivered more closely – if not exactly – to where it was intended.
The Calypso® 4D localization system is a state-of-the-art system to ensure that the radiation is precisely delivered to the target, in hopes of making the treatment both safer and more effective. It is often referred to as “GPS for the Body®”, as it tracks the exact position and motion of the target prior to and during daily treatments.
While the Calypso System is being investigated for use in many parts of the body, it is currently U.S. FDA-approved only for use in treating prostate cancer. This approval was granted by the FDA July 28, 2006.
How does Calypso® work?
The Calypso System is different from other methods to prepare patients for radiation treatment for the prostate. The Calypso System uses radiofrequency waves which allow for very accurate alignment of the prostate before each treatment session. It can also be used to monitor the position of the prostate at all times throughout each treatment session over the entire radiation treatment course.
Three tiny Beacon® electromagnetic transponders are implanted into the target tissue, in this case, the prostate gland. This is a simple outpatient procedure very similar to a routine transrectal ultrasound-guided prostate biopsy. These transponders are inert, and NOT radioactive, meaning that there are no significant interactions with the normal tissue.
Beacon® electromagnetic transponder ( 8 mm in length)
Beacon® electromagnetic transponders situated in schematic of prostate
Later, at the time of the daily radiation treatments, the Beacon® transponders communicate with the Calypso System using safe radiofrequency waves. The Calypso System shows exactly where the target (prostate) is at all times so your doctor can make important and timely decisions about your care using real-time information during radiation therapy.
The Calypso System shows exactly where the target (prostate) is at all times so your doctor can make important and timely decisions about your care using real-time information during radiation therapy.
(See Above) A Calypso System monitor display allows the therapist to know the exact position of the prostate continuously throughout radiation treatment delivery. When the prostate is out of position (due to organ motion), the graph is color-coded to alert the radiation therapist during treatment. If the therapist sees the color yellow on the screen, as shown in this photo, the therapist is alerted to stop the radiation beam and reposition the patient. The yellow color means that the prostate has drifted (due to organ motion) out of tolerance, and that the beam is adjusted so that it is aiming at the target again. Exactly how much organ motion is considered within tolerance and how much is not is pre-defined by your physician.