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Dose delivery error detection by a computer‐controlled linear accelerator
Author(s) -
Loyd M.,
Chow H.,
Laxton J.,
Rosen I.,
Lane R.
Publication year - 1989
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 - 10.1118/1.596384
Subject(s) - linear particle accelerator , collimator , collimated light , monitor unit , backscatter (email) , optics , dosimetry , scattering , beam (structure) , physics , nuclear medicine , computer science , laser , medicine , telecommunications , wireless
A commercial dual photon energy, computer‐controlled linear accelerator has a complex collimation and beam delivery system. For accurate dose delivery, six separate motorized elements must be properly positioned for a given beam selection. Experimentally instituted misalignments of the primary electron scattering foils, the primary collimator, the flattening filter, the scattering foil carousel, and the backscatter shield or shutter produced significant dose delivery errors. The ability of the Mylar window monitor chamber to detect these errors was examined for x‐ray beams. The fault detection system failed to interrupt dose delivery in a number of situations where the error in dose per monitor unit delivered ranged from −6% to +270% of the calibrated value.