This Article Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Plane, J. H. Articles by Trevor, M. M. Search for Related Content PubMed PubMed Citation Articles by Plane, J. H. Articles by Trevor, M. M.

Virtual source distances and field geometry independent output factors for 5–14 MeV electron beams from a Siemens Mevatron M7145

Regional Medical Physics Department, South Cleveland Hospital, Marton Road, Middlesbrough, Cleveland TS4 3BW, UK

This excerpt was created in the absence of an abstract.

It is well established that an inverse square factor based on virtual source distance (VSD) corrects for an air space between the electron applicator and the skin surface (ICRU, 1972; Almond, 1976). Values of VSD have been measured for electron fields of a Siemens Mevatron M7145. Double scattering foils and collimators above the applicator reduce scatter from the applicator walls. As a result some virtual sources are near to the electron window. However, there is some variation with energy and field size.

Key Words: Virtual source distances • Output factors • Electron beams

Received for publication October 30, 1991. Revision received March 16, 1992. Accepted for publication April 7, 1992.