BOSTON, Sept. 24 Cancer treatment specialistsreported yesterday how new technologies are enabling them to provide faster,more accurate cancer treatments than was possible with earlier generations ofradiotherapy technology. In presentations given at an "Emerging Technologies"Symposium sponsored by Varian Medical Systems (NYSE: VAR) in connection withthe annual meeting of the American Society for Therapeutic Radiology andOncology (ASTRO), doctors detailed how they are using RapidArc(TM)radiotherapy technology, as well as cone-beam CT (3-D) imaging to offer theirpatients highly-accurate and more comfortable cancer treatments.
The symposium presentations began with Clif Ling, PhD, a renowned expertin the fields of medical physics and radiation oncology. In his talk entitled"Affirming the past -- anticipating the future -- comments during the 50thAnniversary of ASTRO" he provided a history of the technological advances,many of which were provided by Varian, that have led to improved clinicaloutcomes and increased survival among cancer patients treated withradiotherapy. According to Ling, the technical advances in radiation oncologycan be summarized in four categories:
The Promise of RapidArc
Using Varian's RapidArc radiotherapy technology in the treatment of braintumors, Ben Slotman, who is professor and chairman of the Department ofRadiation Oncology at the VU University Medical Center in Amsterdam,Netherlands, said he was able to shorten his treatment protocols by an hour ormore per patient. Slotman delivered whole-brain radiotherapy plus anintegrated stereotactic boost in five sessions that took fifteen minutes perday from start to finish (including imaging, patient positioning, andtreatment). "The main benefit to integrating the stereotactic boost by usingRapidArc is the fact that the patient does not have to lie still for anadditional 60-90 minutes," Slotman said.
"The delivery of a RapidArc treatment is very fast, which has importantclinical implications," he added. "Treatment times are much shorter, so thereis less chance that a patient will move during treatment, which helps toensure accurate targeting. Another clear benefit is that it is morecomfortable for patients and more patients can be treated in a single day," hesaid.
Slotman and his colleagues compared RapidArc treatment plans with plansfor conventional IMRT. The RapidArc plans were faster to create, he said, andthey produced equal or better dose distributions with superior protection ofsurrounding healthy tissues.
Advances in Image-Guided Radiosurgery with the Novalis Tx Platform
Three-dimensional cone-beam CT imaging is enabling Benjamin Movsas, MD, tooffer his patients image-guided stereotactic radiotherapy and radiosurgerytreatments without the invasive process of planting fiducial markers, such asgold seeds, into the tumors. Using the On-Board Imager(TM) device on a newNovalis Tx(TM) treatment platform, Movsas and his clinical team can generate3-D images that show soft tissue structures, such as the tumor and surroundingorgans, making fiducial markers unnecessary.
"It's often not possible to place fiducial markers into lung tumorswithout risking the possibility of a collapsed lung or other injury," saidMovsas, who is chairman of the Department of Radiation Oncology at Henry FordHospital in Detroit. "Even when fiducials can be safely used, a cone-beam CTimage is still critical because it shows us key information about the tumoritself, like changes in the tumor volume or shape over time."
In addition to the On-Board Imager, the Novalis Tx platform at Henry FordHospital in Detroit incorporates ExacTrak(R) room-based X-ray imaging system,and having both offers some key advantages, Movsas said. "While cone-beam CTcan provide us with in depth data about the targeted tumor, ExacTrak can beused strategically, to take a "snap