Leading Cancer Center Uses High-Intensity Radiotherapy to Deliver Precise Brain Radiosurgery

Clinicians at one of Scotland’s largest radiotherapy departments have begun brain radiosurgery treatments that enable patients to spend less time on the treatment table while increasing precision by minimizing the chance of movement during treatment.

Physicians from the Beatson West of Scotland Cancer Center (Glasgow, UK) have begun delivering the innovative treatments using a TrueBeam STx linear accelerator from Varian Medical Systems (Palo Alto, CA, USA).

A 71-year-old female with breast cancer that spread to her brain received the first of these radiosurgery treatments for two small brain metastases--only 5 mm and 6 mm in diameter--in just one treatment. “Reducing the time the patient spends on the treatment couch is not only easier on the patient but also reduces the opportunity for movement during the treatment, which helps enhance precision,” said clinical oncologist Dr. Brian Clark. “Without the TrueBeam system’s high intensity mode the patient would have received single-fraction fixed beam radiosurgery, taking 45-60 minutes to deliver, with all the inherent problems of potential movement.”

In addition to the high intensity mode, the first treatment at Glasgow utilized Varian’s RapidArc technology for dose delivery, further expediting the treatment. The technology makes it possible to complete a precise treatment by delivering dose continuously during just one or two rotations of the machine around the patient. During a RapidArc treatment, the beam is continually shaped and reshaped to closely conform the dose to the size, shape, and location of the tumor and minimize the dose to surrounding healthy tissue. By using a two-arc approach and delivering the dose at 2,400 monitor units per minute--twice as fast as standard linear accelerators--doctors at Glasgow were able to deliver the full prescribed radiosurgery dose of 25 Gy within a single session, with a “beam on” time of five minutes.

“As soon as we installed the TrueBeam system we wanted to start utilizing the high intensity mode together with RapidArc to deliver higher doses in a single treatment session,” said Garry Currie, head of radiotherapy physics. “The RapidArc planning capability and superior imaging enable us to achieve very high precision, giving us the confidence to deliver such a high dose in a single session to carry out what is effectively a noninvasive technique on small brain metastases.”

Mr. Currie reported that following the success of early TrueBeam high intensity mode treatments, the technique will be utilized for all radiosurgical treatments at the hospital, including stereotactic ablative body radiotherapy (SABR) in the rest of the body.

The Beatson West of Scotland Cancer Center treats more than 7,000 patients each year on 11 Varian medical linear accelerators. With a catchment area enocmpassing 50% the population of Scotland, the center has a history of groundbreaking radiotherapy treatments.

Designed to advance the treatment of lung, breast, prostate, gynecologic, liver, head and neck, and other types of cancer, TrueBeam features technical developments that dynamically synchronize imaging, patient positioning, motion management, and treatment delivery. The TrueBeam STx is optimized for radiosurgical applications, where very large doses are delivered in a single treatment or only a few sessions.

Related Links:
Beatson West of Scotland Cancer Center
Varian Medical Systems