title: High energy photon beam percent depth dose curves.
abstract: The percent depth dose of 8 MV and 18 MV photon beams were measured for various field sizes. The percent depth dose curves exhibited crossed over at selective depth in phantom. Hence, the percent depth dose increases at shallower depth, is independent at crossed over depth, and decreases at deeper depth with decreasing field size. This peculiar phenomenon, which cannot be explained using the primary and scattered radiation concept, should be noted.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA.
authors.forename: C B
authors.initials: CB
authors.lastname: Saw
authors.forename: C
authors.initials: C
authors.lastname: Berta
authors.forename: A
authors.initials: A
authors.lastname: Wu
mesh_terms: D006801:Humans; D008961:Models, Structural; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy