Treating patients with the NPTC accelerator based proton treatment facility

The Northeast Proton Therapy Center (NPTC) at Massachusetts General Hospital has been treating patients with proton beams since November 2001. Over 200 patients were treated in the first year of operation. This facility has replaced the program at the Harvard Cyclotron Laboratory (HCL) where proton treatments had been underway for over three decades. Features such as rotating gantries and deeper proton penetration allow a wider range of clinical applications at this new facility. The requirements of accelerator reproducibility and availability are perhaps at a higher level than those required at an accelerator based physics facility. These requirements and the system performance will be highlighted in this paper. Operation of a proton cyclotron produced by industry (Ion Beam Applications) and the four operating beam lines along with the Gantries and patient-positioning systems will be discussed. Of particular interest in addition to the required availability is the systematic approach to safety and accuracy in the design and implementation.