Alpha Particle and Proton Beams in Therapy

John H. Lawrence, MD, DSc; Cornelius A. Tobias, PhD; James L. Born, MD; Alexander Gottschalk, MD; John A. Linfoot, MD; Robert P. Kling, MD
JAMA. 1963;186(3):236-245. doi:10.1001/jama.1963.63710030018011.
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HEAVY PARTICLES, either charged or uncharged, are called "heavy" because they actually are very heavy when compared with the weight of the electron. The neutron is approximately 1,800 times the weight of the electron and, in the case of other heavy particles, such as alpha particles, carbon nuclei, and other elements higher in the periodic table, they are proportionately heavier according to the number of protons and neutrons within their nuclei. These heavy particles have many interesting physical characteristics— For editorial comment, see page 254. especially their ability to produce dense ionization in tissue. In 1935, when these particles became available for experimental studies in the field of radiobiology, this known physical quality led us to investigate their biological effects on normal tissue.1,2 We found that per unit of ionization produced in tissue they were several times as destructive as equal doses of conventional x-rays. This led to setting


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