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Unexpectedly large dose rate dependent output from a linear accelerator
Author(s) -
Cheng Pocheng,
Kubo Hideo
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 - 10.1118/1.596192
Subject(s) - linear particle accelerator , absorbed dose , dose rate , calibration , dosimetry , physics , nuclear medicine , monitor unit , cathode ray , electronics , particle accelerator , medical physics , beam (structure) , nuclear engineering , nuclear physics , electron , optics , electrical engineering , engineering , medicine , quantum mechanics
During our routine calibration of a Varian Clinac‐20 linear accelerator, the absorbed dose for a fixed monitor unit (mu) was found to decrease with increasing dose rate. Between dose rates of 100 and 500 mu/min, there was up to 20% difference in absorbed dose for a 20‐MeV electron beam. The cause of this problem was a failure in the electronics circuit of an integrating board. This paper presents our analysis of the problem and suggests a possible means of isolating such a failure to warn technologists, physicists, and engineers.