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A review of the reliability of chamber factors used clinically in the United States (1968–1976)
Author(s) -
Hanson W. F.,
Grant W.,
Kennedy P.,
Cundiff J. H.,
Gag W. F.,
Berkley L. W.,
Shalek R. 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 - 10.1118/1.594449
Subject(s) - electrometer , ionization chamber , calibration , reliability (semiconductor) , dosimetry , medical physics , physics , radiological weapon , nuclear medicine , ionization , optics , medicine , ion , power (physics) , quantum mechanics , radiology
One of the principle concerns of a physicist responsible for calibrating megavoltage radiotherapy equipment is the validity and stability of the 60 Co exposure correction factor assigned to his ionization‐chamber and electrometer system. It is the practice of the AAPM Radiological Physics Center (RPC) to perform an intercomparison between the RPC chamber and electrometer system and the chamber and electrometer in use at each of the various institutions visited by the RPC. The results of 202 such intercomparisons are reviewed to determine (1) the consistency in the assignment of exposure correction factors by a calibrating agency with itself and with other calibrating agencies, and (2) the dependence of the reliability of the exposure correction factors upon the type of field instrument and the time since calibration.