Results of tumor treatments with alpha particles and heavy ions at Lawrence Berkeley Laboratory

A clinical trial, starting with 934 MeV helium ions produced at the 184-inch cyclotron, has been underway at Lawrence Berkeley Laboratory since 1975. Eighty-five cancer patients have been treated in a pilot series with the helium ion beam. Treatment techniques have been developed for large field, fractionated, spread out Bragg peak charged particle radiotherapy. A treatment planning computer routine has been developed to compute physical and biological isodoses for charged particle beams taking into account beam perturbations by varying tissue densities as determined by CT scanning. An RBE of 1.2 for fractionated helium ion therapy has been clinically confirmed using daily doses of 200 photon equivalent rad per fraction, four fractions per week to total doses of 6000 rad. Pilot studies with heavier ions (carbon and neon) have started at the Bevalac. Patients with locally advanced malignancies not amenable to conventional therapy will be selected for pilot irradiation with carbon and neon ions. The goal of the pilot studies is a prospective clinical trial utilizing helium ions to evaluate the advantages of improved dose localization, and carbon or neon ions to study the increased biological effect and improved dose localization available with heavy charged particle therapy. (author)