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Physical characteristics of a miniature multileaf collimator
Author(s) -
Xia P.,
Geis P.,
Xing L.,
Ma C.,
Findley D.,
Forster K.,
Boyer A.
Publication year - 1999
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 - 10.1118/1.598478
Subject(s) - multileaf collimator , penumbra , collimated light , collimator , linear particle accelerator , aperture (computer memory) , optics , field size , dosimetry , nuclear medicine , physics , beam (structure) , medicine , acoustics , laser , ischemia , cardiology
A preliminary study of the physical characteristics of a miniature multileaf collimator (mMLC) used with 4 MV x rays is reported. The mMLC attached to the accessory mount of a class C or D Varian linear accelerator (Varian Oncology Systems, Palo Alto, CA) with a source to aperture distance of 65 cm. The field penumbra using the small leaves was found to be consistent with the anticipated field penumbra using photon jaws at the same source to aperture distance as the mMLC. The percentage depth dose values of square fields were found to be consistent with the fields collimated with the upper and lower jaws. Output factors for the very small fields were found to vary rapidly. Circular fields could be produced with depth dose characteristics similar to those produced using conical tertiary collimators, commonly used for radiosurgery, but with a broader penumbra.