Imaging Technology News 9/08

> > special report SBRT - The New Treatment of Choice Higher doses, less damage, fewer treatments put SBRT at the forefront of RT’s future. by Amy Lillard “There will be widespread adoption of SBRT throughout the oncology community” ontouring dose with pinpoint, multidimensional accuracy, targeting a tumor without damaging surrounding tissue and destroying a tumor in one radiation session is still a lofty goal in radiation therapy, and rarely attainable. For years, radiation oncologists and physicists have longed for technology to match their need for imaging and radiation delivery methods that hit all of these objectives. With the advent of stereotactic body radiation therapy (SBRT), the imaging community might finally have a tool that provides maximum benefit for physicians and patients. Why is SBRT the technology of the future in the field of radiotherapy? What systems exist, and what must be done before widespread adoption in the field? As more studies demonstrate the improved success of - Timothy D. Solberg, Ph.D., FACMP, FAAPM, using SBRT over conventional methods University of Texas Southwestern Medical Center such as IMRT or IGRT, it becomes clearer that this novel technique may become the treatment of choice in radiation therapy’s near future. C malignant or benign tumors that are small, may be hard to reach and are located typically in the head or neck, lung, liver, in various abdominal sites and the prostate. With tighter margins, less normal tissue is affected so there are fewer side effects for patients. Plus, fewer treatment sessions are required to deliver the same total amount of radiation. The proof is in the imaging Extending this technique to the body required advances in imaging, radiation delivery and patient placement. New SBRT systems that image, localize and sculpt radiation for small to moderate-sized tumors in the body is now available. “The advances occurring in radiotherapy are unprecedented,” said Cal Huntzinger, manager of marketing and engineering, surgical sciences, Varian Medical Systems. “With our new SBRT systems, we have the ability to identify targets in ways we never could before, driven by the power of functional images combined with structural images. Oncologists and referring physicians can visualize exactly what they’re trying to Advantages of SBRT treat without guessing. During treatment, physicians can sculpt • Delivers high doses of radiathe dose in ways that were tion more precisely unheard of just years ago.” • Fewer treatment sessions are The key to the new capabilirequired to deliver the same ties of SBRT is significant total amount of radiation advancements in imaging. • Less healthy tissue is damWhile in the past radiotherapy aged, resulting in fewer side and radiosurgery primarily used effects for patients CT scans for target identification and treatment, scans that often lacked exactness and quality, today the imaging community has highly enhanced CT capabilities as well as MRI, PET/CT and SPECT/CT imaging. Better image quality enables greater accuracy in patient positioning, targeting the tumor as well as tracking the lesion during treatment. This minute localization offers customization and safety at unparalleled levels. Targeting hard to reach tumors Radiation therapy has evolved as a delicate balance between delivering the right dose and not damaging surrounding healthy tissue. With conventional external beam radiation therapy, a significant portion of surrounding normal tissue also receives dose to avoid missing the tumor or lesion. This inescapable fact of radiation therapy is due primarily to technical limitations, including the inability to target precisely with existing imaging and radiation delivery methods. Add to that the normal movements of organs and difficulties in patient positioning, and typical radiotherapy could help but also hurt the patient. More recent radiosurgery methods have attempted to increase precision and remove dosing of healthy tissue. New procedures deliver large radiation doses to tumors and other targets in single or small numbers of sessions, ideally without harming the surrounding healthy tissue. In order to do this companies and tools have experimented with increased radiation delivery speed, dose sculpting and enhanced imaging capabilities. But for the most part, there has not been an option that has included all of the above. With SBRT, the imaging community is seeing this advance come to life. Stereotactic radiosurgery and radiotherapy have been successfully used for intracranial, orbital and base-of-skull tumors to accurately locate and dose tumors in three-dimensional space. Like these techniques, NovalisTX’s imaging options include SBRT involves patient immobilization and stereo X-ray 6D targeting, cone-beam image-guided radiation therapy (IGRT). As a CT and fluoroscopy. subspecialty of IGRT, SBRT enables delivery of Photo courtesy of Varian Medical extremely precise high doses of radiation to 28 > special report > S e p t e m b e r 2 0 0 8 The right indications for SBRT While SBRT represents a significant advancement in radiation therapy, determining the best methods and indications for use is currently a matter for careful analysis. “We view SBRT as a very important emerging technology in the spectrum of cancer care, but feel it should first be performed in a very controlled and systematic fashion under clinical trials,” said Timothy D. Solberg, Ph.D., FACMP, FAAPM, professor and director, department of radiation oncology, University of Texas Southwestern Medical Center. “There’s significant promise from this technology, and preliminary studies are showing it as an effective and safe treatment. But there is potential for adverse effects if used improperly, and there is much to learn about its ideal use.” From a technical point of view, the aspects of SBRT that are so exciting are also the most challenging. The confluence of imaging, positioning, tumor motion and high radiation presents much room for error and much to SBRT continued on page 31 http://new.reillycomm.com/imaging/special-report-b.php

Table of Contents Feed for the Digital Edition of Imaging Technology News 9/08

Imaging Technology News 9/08 Contents IGRT How IGRT Targets the Prostate ASTRO Oncology Information Management Systems (OIMS) Imaging Leading the Intense Race Against Cancer SBRT - The New Treatment of Choice Top IMRT/IGRT Centers to Watch Molecular Imaging: Ready for the Limelight CR or DR in the ER? Have You Hit the Glass Ceiling?

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