ABSTRACT
Although proton therapy was proposed more than 65 years ago (Wilson 1946) and rst performed clinically in 1954 (ICRU 1998), by 2009, a mere 28 proton therapy centers were operating worldwide, only seven of which were in the United States. Today, less than 1% of all radiotherapy patients receive proton therapy. Consequently, the literature contains comparatively few reports on quality assurance (QA) for proton therapy.
