Status Report for the Harper Hospital Superconducting Cyclotron Neutron Therapy Facility

During the past three years the number of neutron therapy patients treated at the Gershenson Radiation Oncology Center has remained approximately constant. The facility is operating at maximum load, approximately 9500 fields per year. In the present paper, data for the clinical load and usage of the cyclotron, since it entered routine clinical operation March 1992 are presented, together with data on machine downtime for the period March 1993 – February 2001. Recent and ongoing cyclotron improvement projects are described, including redesign work on the ion source, the beryllium target, the cryogenic and vacuum systems. The major improvement project, however, is the construction of a computer controlled multileaf collimator (MLC) to replace the existing multirod collimator[1] (MRC), which has been in use since patient treatments started in September 1991.