Proton Radiobiology, Radiosurgery and Radiotherapy

This review briefly traces the historical developments of proton radiobiology, radiosurgery and radiotherapy for the benefit of young researchers and clinicians entering into this field. In preparing to use protons in radiosurgery and radiotherapy, radiobiological effects of protons were studied extensively by various groups, including the University of California at Berkeley, the University of Uppsala, Massachusetts General Hospital, and the Harvard Cyclotron Laboratory. Considerable work on proton radiobiology was also done because protons are a major component of the radiation environment in space. The biological effects of proton beams were found to be quantitatively and qualitatively similar to conventional radiations used in radiotherapy. The relative biological effectiveness (RBE) of protons suitable for large-field radiotherapy, compared with 60Co γ-rays, is generally in the range 1·0–1·25, and remains the same with depth of penetration, except for the descending portion of the depth-dose curve. A...