Premium
Exceptional increases in electron cone output as the backup diaphragms are opened
Author(s) -
Lightstone A. W.,
Videla N.,
Mason D. L. D.
Publication year - 1997
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597913
Subject(s) - electron , physics , backup , optics , cone (formal languages) , computer science , nuclear physics , algorithm , database
Some linac manufacturers provide cones for defining circular electron fields. During commissioning of one of our new radiotherapy units, we noted that the output of these cones has a strong dependence on the diaphragm opening that precedes the cone. In particular, for the 8 MeV beam, the output of a 3 cm diameter cone increased by more than a factor of 2 as the diaphragm was opened from 5×5 to 20×20 cm. One concludes that the particular mechanical design results in an output factor dependency that is exceptional when compared to the data presented in standard texts such as Khan's “The Physics of Radiation Therapy.” The importance of quality assurance and communications with the manufacturer is underscored by this example.