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Elongation effects on the Therac 6 linear accelerator
Author(s) -
Dawson Donald J.
Publication year - 1978
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 - 10.1118/1.594508
Subject(s) - collimator , linear particle accelerator , square (algebra) , elongation , physics , optics , dosimetry , field (mathematics) , mathematics , geometry , nuclear medicine , materials science , beam (structure) , medicine , metallurgy , ultimate tensile strength , pure mathematics
The effects of field elongation on the central‐axis output at d max and on the depth‐dose curves for the 6‐MV x rays from the Therac 6 linear accelerator are considered. These parameters are independent of the collimator angle for both square and elongated fields. The exchange of collimator pairs results in significant output differences but has a negligible effect on the depth‐dose curves. Both the central‐axis output at d max and the depth‐dose curves agree satisfactorily with the predictions of the equivalent‐square technique. An alternative method of greater accuracy is also indicated for the prediction of central‐axis outputs at d max for elongated fields.