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Mechanical and radiation isocenter coincidence: An experience in linear accelerator alignment
Author(s) -
Woo M. K.,
O'Brien P.,
Gillies B.,
Etheridge R.
Publication year - 1992
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 - 10.1118/1.596866
Subject(s) - isocenter , linear particle accelerator , dosimetry , physics , coincidence , medical imaging , radiation , particle accelerator , optics , medical physics , nuclear medicine , nuclear physics , computer science , beam (structure) , medicine , artificial intelligence , imaging phantom , alternative medicine , pathology
As part of the commissioning procedure of a linear accelerator at our cancer center, the defining laser lines were aligned with the optical and radiation isocenter of the linac. When a mechanical checkout jig was set up at the same point, a discrepancy of 4 mm resulted when the gantry was moved from 0° to 180°. Extensive measurements, some with custom‐designed devices, confirmed the observations and provided an explanation. Even though the mechanical isocenter is within the specified tolerence of 1‐mm radius, the clinically observable discrepancy of 4‐mm results from the noncoincidence of the mechanical and radiation isocenters. The clincial significance of the final setup is discussed and future commissioning procedures are recommended.