Current Definition in Teleradiotherapy Treatment Phase and Brachytherapy Treatment Phase: "A phase ends when there is a change in the irradiated volume, treatment fraction size, modality, or treatment technique." I think this still suggests too much that phases are expected to be sequential with one phase ending and then other phase starting. Phases may be sequential, but just as well interleaved or treated in parallel. Also "fraction size", currently used in Bracy Phase only, is confusing. 

Proposed Change: Us the same as in description of Course Summary: “A phase consists of a set of identical fractions. In this context, identical means that each fraction uses the same modality, technique, dose per fraction, and is applied to the same treatment volume or volumes. Because of their spatial relationship or the technique used, all treatment volumes do not necessarily receive the same total dose during a phase.”