Varian Medical Systems out of Palo Alto, California has announced that its new RapidArc™ intensity-modulated stereotactic radiotherapy machine has been used for the first time on a patient with a soft tissue tumor in his thigh.
RapidArc makes it possible to quickly deliver an advanced image-guided, intensity-modulated radiation therapy (IMRT) treatment with one 360 degree rotation of the treatment machine around the patient. In this case, however, Scarbrough [Todd Scarbrough, M.D., radiation oncologist and director of the Melbourne Internal Medical Associates, Florida –ed.] and his team designed a treatment that was delivered with just half a rotation around the patient.
"The tumor was near the surface of his thigh, so a full arc would have exposed too much of his normal leg to the treatment beam," Scarbrough said.
Scarbrough’s team planned the RapidArc treatment using Varian’s Eclipse™ treatment planning software, which allowed them to visualize how the dose would be distributed within the patient’s leg. "The RapidArc plan gave us a dose distribution that was superior to what we could have achieved with traditional IMRT," Scarbrough said. "Eclipse made it easy to create a plan that would avoid the previously-irradiated tissues. We just superimposed the dose distribution from his earlier treatments onto the new CT scans, created a structure out of that area, and instructed the software to avoid it as if it were a critical organ. It was very easy to do."
Stereotactic body radiotherapy involves delivering higher-than-usual doses of radiation to a tumor over a shorter-than-usual timeframe. It requires great accuracy and precision, both in terms of targeting and in terms of beam shaping, to minimize the exposure of surrounding tissues. MIMA’s RapidArc protocol achieves the necessary level of precision. 3-D X-ray images of the targeted area are used to fine-tune patient positioning prior to each treatment. Then, as the treatment machine rotates around the patient, the treatment beam is continually shaped and reshaped to match the dimensions of the tumor.
Press release: MIMA Cancer Center Becomes First in World to Treat Soft Tissue Carcinoma With Stereotactic Body Radiotherapy Using RapidArc™ Radiotherapy Technology…
Product page: RapidArc™ Radiotherapy…
Product brochure (.pdf)…
