Swiss cancer clinic begins use of Varian superconducting cyclotron
Clinicians at the Paul Scherrer Institute in Switzerland have begun clinical treatments using the world’s first commercial superconducting cyclotron for routine medical use, enabling high-precision proton therapy treatments for a range of cancer patients. The new cyclotron is from Varian Medical Systems’ Accel group.

Dr. Martin Jermann, head of the PROSCAN proton therapy program at the Paul Scherrer Institute (PSI), said, “The first treatments went smoothly and we intend to increase the number of patients treated per day to ten over the next few weeks. The objective of such proton therapy treatments is to cure the patients and to minimize both short-term and long-term side effects.” 

The Varian/Accel superconducting cyclotron represents a dedicated proton source for the PSI equipment, with beam-lines to supply up to 250 MeV protons to the spot-scanning gantry for deep-seated tumor treatments.

The spot-scanning technique developed at PSI enables malignant tumors to be targeted with high precision deep inside in the body, and their growth successfully stopped, without damaging healthy tissue around the target area.  Protons have excellent physical properties for radiation therapy which enable clinicians to very precisely control the shape of the dose distribution inside the patient's body. The depth of the proton beam can be precisely controlled, which means healthy tissue behind the tumor can be spared as effectively as adjacent tissue.

Jermann said that the new cyclotron would allow the institute’s proton therapy facility to operate all year rather than being limited to just 6-8 months, as was the case with the department’s previous equipment. “In addition, the beam characteristics and dynamics will allow the development of advanced scanning features, which should enable us to image and treat moving tumors in the lung and breast with extremely high precision,” he said.

The Varian/Accel superconducting cyclotron, degrader, beam line and gantries will enable PSI to maintain and enhance its international reputation as a unique high-tech laboratory for advanced proton therapy as well as a leading clinical proton therapy research center, Varian said.

Jermann added that “in the future, 150-250 patients per year will benefit from advances in deep-seated tumor therapy at PSI, in addition to the 200-300 eye cancer patients already being treated, with success rates of more than 98 percent.”