Unique Tissue Depth Response to Electron Irradiation

Observations are presented on what appeared to be a unique depth effect of a monoenergetic electron beam (2.0 Mpv). Changes related to the incident beam were identified in swine to a depth of 3 cm grossly and confirmed by histologic study as typical of radiation effect. This is in contrast to the generally accepted penetration of 2.0-Mev electrons of approximately 1 cm. Various factors of dosimetry and tissue effect are discussed, without a clear explanation of the lesion observed. The 1-cm beam penetration was confirmed in nonliving tissue- equivalent materials.