The K100 Neutron-therapy Cyclotron

The first superconducting cyclotron for medicine was designed and constructed at NSCL and is now in use for cancer treatment at the Gershenson Radiation Oncology Center at Harper University Hospital in Detroit. It was completed at NSCL in 1990 and was then moved to Detroit to be installed in the hospital.

Checking the alignment of a patient about to receive treatment on the K100 neutron-therapy cyclotron. more

The cyclotron itself accelerates deuterons. Sometimes known as “heavy hydrogen,” deuterons differ from normal hydrogen in that they have a neutron as well as a proton in their nucleus. The cyclotron’s fast-moving deuterons are stopped in a target of beryllium just before their exit from the cyclotron. This produces a beam of high-energy neutrons, which is then directed against the cancer patient’s tumor.

Since the cyclotron is superconducting, its physical size is much smaller than a room-temperature cyclotron would be. This “miniaturization” allows the cyclotron to be mounted on gantry rings that rotate around the patient so that the cancer can be irradiated from several angles. The Harper facility has become the most active neutron-therapy center in the world, and a new treatment modality using a combination of neutrons and x-rays has been found to be particularly effective for the treatment of advanced prostate cancer.