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Evaluation of a beam‐spot camera for megavoltage x rays
Author(s) -
Lutz Wendell R.,
Maleki Nasser,
Bjärngard Bengt E.
Publication year - 1988
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 - 10.1118/1.596214
Subject(s) - microdensitometer , optics , beam (structure) , materials science , radiography , computed radiography , laser beam quality , calibration , image quality , physics , computer science , laser beams , artificial intelligence , laser , quantum mechanics , nuclear physics , image (mathematics)
A beam‐spot camera for measurements of x‐ray focal spots of accelerators has been evaluated. The device consists of closely packed 0.25‐mm‐thick lead and 0.25‐mm‐thick cardboard strips. It is placed on radiographic film with the lamellae parallel to the beam axis and an exposure made. The images were scanned with a microdensitometer. The results indicate that the broadening of the source intensity profile at half maximum is of the order 1 mm, which permits the use of the beam‐spot camera for acceptance testing and quality control. Longer tails in the density profile limit the quantitative information that can be extracted from the images.