Open AccessCorrections to traditional methods of verifying tangential‐breast 3D monitor‐unit calculations: Use of an equivalent triangle to estimate effective fields
Author(s) -
Prado Karl L.,
Kirsner Steven M.,
Erice Rolly C.
Publication year - 2003
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1120/jacmp.v4i1.2541
Subject(s) - monitor unit , field (mathematics) , scattering , oblique case , beam (structure) , computer science , mathematics , physics , optics , nuclear medicine , medicine , linguistics , philosophy , pure mathematics
This paper describes an innovative method for correctly estimating the effective field size of tangential‐breast fields. The method uses an “equivalent triangle” to verify intact breast tangential field monitor‐unit settings calculated by a 3D planning system to within 2%. The effects on verification calculations of loss of full scatter due to beam oblique incidence, proximity to field boundaries, and reduced scattering volumes are handled properly. The methodology is validated by comparing calculations performed by the 3D planning system with the respective verification estimates. The accuracy of this technique is established for dose calculations both with and without heterogeneity corrections. © 2003 American College of Medical Physics. PACS number(s): 87.53.– j