Calypso Medical (Seattle) launched its Calypso 4D Localization System at the 48th annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO; Fairfax, Virginia) that ended yesterday in Philadelphia.

Calypso received FDA 510(k) clearance for the system in July for use with imaging systems for the prostate, which is subject to movement during imaging. The Calypso system uses electromagnetic technology in conjunction with implanted Beacon Electromagnetic Transponders designed to provide “objective, accurate and continuous tumor location information during external beam radiation therapy.”

Eric Meier, president/CEO of Calypso, told Medical Device Daily that the system is the only one of its kind to pinpoint target location during imaging that is non-ionizing, or in other words, not releasing radiation.

The systems’ transponders — smaller than a grain of rice — are placed “in proximity to the tumor,” Meier said. When the transponders are coupled with the localization system, they send out “objective location instructions” to the radiation therapist “to register the patient’s treatment target to isocenter prior to treatment.”

The problem is that, due to respiration and other body movements and functions, organs move during radiation therapy. Thus, Calypso’s system is designed to help radiation therapists make appropriate adjustments during treatment.

The system was evaluated in patients undergoing prostate radiation treatment between 2003 and 2006 at leading cancer centers. In those studies, investigators documented clinically-relevant prostate motion present in the majority of patients.

The prostate motion was unpredictable and variable, patient to patient, and throughout the course of treatment. But by using the guidance from the Calypso system, clinicians responded to out-of-threshold conditions in real-time, to manage organ motion with individual protocols.

Calypso also reported two “product collaborations,” one with the Radiology Oncology Systems unit of Philips (Andover, Massachusetts), another with IMPAC Medical Systems (Mountain View, California).

“Integrating continuous, real-time monitoring data with Philips’ treatment planning software system builds on our collaboration agreement to co-develop product offering that advance planning and treatment delivery techniques,” Meier said. “Plans are under way to bring truly adaptive radiation therapy techniques to the clinical community through our collaboration.”

With the collaboration, the Radiation Oncology Systems business of Philips expects to provide enhancements to its treatment planning systems with target localization data from the Calypso 4D Localization System.

Meier said Calypso’s system and collaboration with others provides the “’missing’ link to advance radiation treatment options with continuous target tracking.”

“Today’s highly conformal radiation therapy treatment options relay on knowing the exact location of the target moment to moment,” Meier said.

Meier said that he expects the collaborations to bear results for the next “product introductions.”

Meier also told MDD that the company is investigating uses of its system in other “soft tissues.”

In other news from ASTRO:

• Varian Medical Systems (Palo Alto, California)held a symposium, attended by more than 900 radiation oncology professionals, on the use of new image-guided radiotherapy techniques to improve the effectiveness of cancer care.

Billy Loo Jr., MD, PhD, of Stanford University (Palo Alto, California), focused on strategies for improving the precision of treatments for lung cancer and other thoracic tumors by tracking and compensating for respiratory motion.

Loo’s team uses image sequences that show the extent of tumor motion to plan more precise treatments. The technique enables him to escalate the dose delivered to the tumor while preserving the surrounding healthy tissues.

Karin Haustermans, MD, PhD, of the Department of Radiation Oncology at UZ Gasthuisberg (Leuven, Belgium), discussed ways of using functional imaging — namely, PET-CT and MRI — to detect radiation-resistant regions in rectal cancer in order to target them with higher radiation doses using image-guided treatment delivery techniques.

“Most relapses in high-risk rectal cancer patients occur in areas that were already treated with radiation,” Haustermans said. “The aim of our study was to develop methods of detecting the radiation resistant regions in tumors and target them more aggressively.”

Haustermans described how tumors changed over time during a course of treatment — both in size, shape and metabolic activity. Her team is now comparing different treatment approaches using this information to improve dose distribution and treatment effectiveness.

Alan Pollack, MD, PhD, chairman of the Radiation Oncology Department at Fox Chase Cancer Center (Philadelphia), is leading a clinical study on strategies for shortening the duration of a course of radiotherapy treatment for prostate cancer, normally taking up to eight weeks. His approach involves delivering higher doses with greater precision over fewer treatment sessions, as compared with more conventional treatment approaches.

“Giving higher doses per treatment session has potential advantages, but requires very precise targeting of the prostate to avoid the surrounding normal tissues. We are using 3-D imaging daily before each treatment, which allows for reduced exposure of the bladder and rectum to high radiation doses while ensuring that radiation delivery to the prostate and the potential for tumor eradication are optimized,” Pollack said.