Research Validating Calypso Medical's Dynamic Edge Gating to Be Presented at 2011 Joint AAPM/COMP Meeting

SEATTLE, WA--(Marketwire - Jul 27, 2011) - AAPM Booth #1131 Calypso Medical Technologies, Inc., developer of GPS for the Body^® technology used for the precise tracking of cancerous tumors during prostate radiotherapy, today announced research validating the clinical use of Dynamic Edge™ Gating for managing intra-fraction motion, as well as research about the Calypso^® System's unique organ rotation information for accurate radiation delivery. Data from the abstracts will be presented at the 2011 Joint American Association of Physicists in Medicine (AAPM) and the Canadian Organization of Medical Physicists (COMP) meeting, July 31-August 4 at the Vancouver Convention Centre (Booth #1131).

"The research is very encouraging, as it not only substantiates the accuracy of Dynamic Edge Gating with respect to beam movement when automatically disabled or re-enabled, but it also highlights the value of rotational information, which can only be accessed utilizing the Calypso System," said Lorraine Marshall Wright, chief marketing officer and vice president of Calypso Medical. "These abstracts are important because the results underscore the technology and its potential to enable a further decrease in the side effects associated with prostate cancer radiotherapy."

Dynamic Edge Gating allows therapists to set motion thresholds that disable radiation delivery if the targeted tissue moves outside a clinician-defined preset threshold. The Calypso System, which provides target position information in the form of objective data, previously relied on the therapist to manually intervene and halt radiation delivery when healthy tissue was in danger of receiving unintended radiation. Dynamic Edge Gating Technology automates this function and provides an immediate response so the radiation beam is automatically disabled or re-enabled in response to organ motion.

Washington University School of Medicine reports that the output results of beam stability utilizing Dynamic Edge Gating interface versus non-gated fields was within one percent¹. This degree of accuracy reinforces the utility of the gating capability, which allows physicians to gate the beam in order to prevent the delivery of unintended radiation to healthy tissue.

"The Calypso gating solution uses the actual tumor target as a reference point instead of an external surrogate, therefore the resulting signal sent to the linear accelerator about when to hold or turn the beam on is accurate," said Lakshmi Santanam, Ph.D., assistant professor, department of radiation oncology at Washington University School of Medicine.

Another key scientific presentation focuses on the ability of the Calypso System to measure the amount of rotation exhibited by the prostate during radiation delivery, and to determine the effect of that rotation on the amount of radiation actually delivered². The authors' research concluded that as the effective rotation of the prostate increased, the amount of radiation delivered to the prostate decreased thereby leading to significant under-dosing of the tumor if left unmanaged. The Calypso system is the only technology that provides rotational measurement information to allow physicians to create patient-specific rotational tolerances and individualized PTV margins necessary for accurate dosage management.

Calypso technology is also the topic of four additional scientific presentations and posters that include refining PTV margins for treatment planning; investigating the dosimetric variability between fiducial markers and Beacon® transponders; analyzing the difference in daily setup using cone beam computed tomography versus Beacon transponders, and the validation of a new 4D algorithm designed to confirm accuracy of dose distribution. In addition to showcasing the Calypso System and Dynamic Edge Gating, the company is also highlighting investigational information about the use of real-time tracking in lung cancer.

About the Calypso System
The Calypso System uses GPS for the Body technology to safely guide radiation delivery during prostate cancer treatment. Beacon electromagnetic transponders, smaller than a grain of rice, are permanently placed in a patient's prostate or prostatic bed. Each transponder emits a unique radio frequency signal to the Calypso System, which then determines the exact location and motion information about the tumor target. Because the tumor can be accurately tracked and monitored, precise targeted radiation can be delivered to the tumor while sparing surrounding healthy tissue and organs. This is critical because any movement by a patient, including internal movement of the tumor, may cause the radiation to miss its intended target and hit adjacent healthy tissue. Calypso's real-time position information allows physicians to safely deliver the maximum cancer radiation treatments directly to the tumor. The Calypso System, cleared by the U.S. Food & Drug Administration (FDA) for use in radiation therapy for the prostate and post-operative prostatic bed, has been used to treat more than 10,000 people worldwide.

About Calypso Medical Technologies, Inc.
Calypso Medical is a privately held medical device company headquartered in Seattle. Its proprietary tumor localization system is designed for body-wide cancers commonly treated with radiation. Utilizing miniaturized, non-ionizing implanted devices called Beacon^® electromagnetic transponders, the Calypso System continuously and accurately tracks the location of cancerous tumors for the improved precision and safe management of radiation for cancer treatment. The real-time position and motion information provided by the Calypso System offers objective reassurance that radiation treatment is delivered precisely to the prescribed target and not to surrounding healthy tissue, thereby improving safety and eliminating unnecessary radiation exposure to patients. The Calypso System was cleared by the U.S. Food & Drug Administration (FDA) for use in radiation therapy for the prostate and post-operative prostatic bed. The company has strategic relationships with Varian Medical Systems, Siemens Healthcare, Elekta Corporation and Philips Medical. Additional information can be found at www.calypsomedical.com.

Calypso, GPS for the Body and Beacon are registered trademarks and Dynamic Edge is a trademark of Calypso Medical Technologies, Inc.

¹Abstract ID 15219 Title: First clinical commissioning of a dynamic gating interface for an electromagnetic tracking system. Santanam, Parikh, et al. Washington University, St. Louis.

²Abstract ID 16814 Title: The Dosimetric Impact of Prostate Rotations During electromagnetically Guided External Beam Radiation Therapy. Amro, et al. University of Michigan, Ann Arbor.