October 24, 2012 — Clinicians at the Harley Street Clinic in London are using the Calypso GPS for the Body system from Varian Medical Systems to provide real-time tracking of tumors during prostate cancer radiotherapy treatments. The first such system to be installed in the United Kingdom, Calypso real-time tracking has been used to enhance the precision and quality of treatments for more than 20 prostate cancer patients at the clinic to date.
"This really is the gold standard for real-time tracking and we are finding that as patients learn about the system, an increasing number are requesting that we make use of Calypso transponders during their treatments," said Neil Livingstone, treatment superintendent. "We hope that an increase in precision may help minimize radiation to healthy tissue while giving our clinicians additional confidence to deliver higher doses."
At the Harley Street Clinic, clinicians are using the real-time tracking capabilities of Calypso to reduce the amount of healthy tissue exposed to the treatment beam. Three Calypso transponders are inserted into the prostate, where they provide continuous real-time information. The position of the markers is tracked continuously throughout a treatment session to help keep the beam on target. If the targeted area moves outside the treatment beam, the treatment is automatically halted.
Another benefit of the system, according to Livingstone, is that patients no longer need to be imaged on a daily basis, avoiding the need for additional X-ray exposure during conventional imaging.
Just as a GPS tracking system in a car can pinpoint where the car is at all times in relation to its destination, Calypso GPS for the body provides continuous real-time information as to the precise location of the prostate. The prostate is not a stationary target. It can shift by as much as several millimeters during a radiotherapy treatment session. The Calypso system enables clinicians to track the prostate in real time during treatment, in order to help enhance treatment precision. There are more than 100 Calypso installations globally and more than 15,000 patients worldwide have been treated using the system.
A clinical study entitled, "Assessing the Impact of Margin Reduction (AIM)," published in the medical journal Urology, demonstrated that the use of Calypso real-time tracking during radiotherapy treatments for prostate cancer resulted in a significant reduction in the majority of serious treatment-related side effects that were studied. 
For more information: www.varian.com
 Sandler, Howard, et al. "Reduction in Patient-reported Acute Morbidity in Prostate Cancer Patients Treated With 81-Gy Intensity-modulated Radiotherapy Using Reduced Planning Target Volume Margins and Electromagnetic Tracking: Assessing the Impact of Margin Reduction Study." Urology 75 no. 5, (2010): 1004-1008.