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A method of beam–couch intersection detection
Author(s) -
Muthuswamy Moorthy S.,
Lam Kwok L.
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 - 10.1118/1.598509
Subject(s) - isocenter , collimator , rotation (mathematics) , intersection (aeronautics) , optics , beam (structure) , linear particle accelerator , translation (biology) , physics , field (mathematics) , mathematics , geometry , imaging phantom , engineering , biochemistry , chemistry , messenger rna , pure mathematics , gene , aerospace engineering
At the time of treatment planning it would be useful to know whether part of the treatment beam passes through the patient/couch support assembly before it passes through the patient. In the previous work of Yorke, the range of gantry angles leading to beam–couch intersection was found as a function of couch translation for symmetric field sizes and for zero couch rotation. Yorke's method has been extended to include couch rotation, dual independent jaws, and multi‐leaf collimator (MLC) field shapes. In addition, the new method is also applicable in the situation of the couch top located above the isocenter. For a clinically treatable, 20 × 20 cm field configuration in a linac, the range of gantry angles leading to beam–couch intersection are different by 6.7 degrees for a couch rotation angle of 25 degrees when compared to no couch rotation. The new method agrees with data within the setup and measurement uncertainties for a variety of field sizes including an oval shaped MLC field, and various couch locations, couch, and collimator rotation angles.