The Project

Using a gantry-based spot scanning technique for irradiating deep-seated tumors, PSI's originaly proton therapy project OPTIS developed with the Gantry 1 project into an entirely new method of proton radiotherapy. The success of this project, and the international interest generated in its technology, led the institute directorate in 1998 to examine strategies for extending the scope of proton therapy at PSI. The medium term goal was to transform the institute's breakthrough in cancer therapy into a marketable product, by developing techniques and equipment in collaboration with industrial partners. In the light of the latest clinical research, PSI's developments for spot scanning is currently being adapted worldwide in hospitals. Further development (Gantry 2 project) will enable moving tumors (e.g. lung carcinomas) to be targeted with the necessary precision, and the success potential of this innovative therapy will become clearer as patient numbers are stepped up.

A pilot study in 1999-2000 plotted the way to achieve the institute's goal, and in fall 2000 PROSCAN was born. In May 2001 the new COMET cyclotron, designed specifically for medical applications, was installed. Manufactured by ACCEL Instruments (incorporated in VARIAN Medical systems today), this superconductive 250 MV facility fulfils PSI's rigorous specifications and will enable proton therapy of deep-seated tumors to continue throughout the year. A further gantry (Gantry 2), currently being tested, will enhance therapeutic options, permitting treatment of moving tumors such as lung and breast carcinomas via ultrafast two-dimensional magnetic multi-scanning techniques. Using variable intensity proton beams, the new gantry will be able to improve still further on the results of the latest developments in variable intensity photon therapy.

With commissioning tests for the COMET cyclotron started early 2005, the new PROSCAN system (using the existing gantry) came on stream for all-year patient therapy in February 2007. In a parallel process the new Gantry 2 is being developed and built, and is due to commence operating with patients in 2012. The OPTIS facility for eye radiotherapy, run at the Philips cyclotron (Injector I) for more than 25 years was transferred to COMET in 2010. New scanning techniques developed during the last 2 years are tested and introduced into the therapy process at the Gantry 2. In parallel to the technical extension of the facility also the medical building and the medical infrastructure are extended in 2011 and 2012, to be prepared for the higher patient throughput.

Designed as a single system, the COMET cyclotron, degrader, beam line and gantries enables PSI to enhance its international reputation as a unique high-tech laboratory for advanced proton therapy as well as a leading clinical proton therapy research center. In the future more than 300 patients per year will benefit from the advances in deep-seated tumor therapy at PSI – in addition to the 200-250 eye cancer patients being treated at the OPTIS facility, with success rates of more than 98%.


The clinical Center of Proton Therapy at PSI (2004).

As project initiator and leader, PSI defines equipment specifications and allocates orders – as far as possible to industrial providers in Switzerland, but also elsewhere. The new proton therapy facility, including the compact superconductive cyclotron and the beam lines, as well as Gantry 2 and the new OPTIS2 horizontal beam treatment room, serves as a benchmark for the construction of future hospital units – a breakthrough in medical technology from which Swiss industry also stands to benefit.

The COMET cyclotron (under construction in 2004).

The investment costs of the project – including construction of OPTIS2, Gantry 2 and the extension of the medical infrastructure – stand at about CHF 70 million. The total investment has been raised by PSI, by sponsors, benefactors, as well as from technology transfer licenses from industry. The sale to industry of marketing rights for PROSCAN technology (including scanning techniques) is an ongoing process. Specialists from PSI also advise hospitals on the applications of proton therapy equipment as well as its specification and purchase. As a leader in R&D of proton therapy technology and of clinical research for proton therapy, PSI also provides widespread training and education in all areas of proton therapy.