Proton Beams in Radiation Therapy

摘要: The rationale for study of proton radiation therapy is that, some anatomic sites and tumors, the treatment volume smaller; i.e., there less irradiation nontarget tissue while target included in three dimensions at each session. As a result, dose to can be raised. consequence that tumor control probability improves frequency severity treatment-related morbidity decrease. These results come about from physical fact range finite; comparison, absorption photons an exponential function and, hence, received full-beam path through body. Accordingly, deep treatments zero beam path. This situation provides virtually certain means improving outcome selected categories patients. Experience date with has been quite limited. June 1991, total number radiation-treated patients was 11,763 various centers. Of number, approximately 46% 32% have treated small benign intracranial lesions (principally pituitary adenomas arteriovenous malformations) tumors eye, respectively. Thus, only 2500 all other types. centers 2800 uveal melanoma are local rate 96% (for failures in-field, marginal, parts eye). chondrosarcomas chordomas skull base 91% 65%, percentages compare 35% achieved conventional treatment. malformations indicates bleeding disappearance lesion comparable those by procedures. developments programs contributed greatly planning, e.g., first three-dimensional planning system put into regular clinical use (uveal melanoma), beam's eye view, digital-reconstructed radiograph, dose-volume histograms, definitions uncertainty around any defined point. potential gains high. In May Proton Radiation Oncology Group formed design, supervise, coordinate trials assist data analysis. efficacy will compared photon very highest technology.