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WE‐G‐BRA‐04: Common Errors and Deficiencies in Radiation Oncology Practice
Author(s) -
Kry S,
Dromgoole L,
Alvarez P,
Lowenstein J,
Molineu A,
Taylor P,
Followill D
Publication year - 2015
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 - 10.1118/1.4926074
Subject(s) - dosimetry , calibration , audit , medical physics , nuclear medicine , quality assurance , medicine , radiation oncology , statistics , mathematics , radiation therapy , radiology , accounting , external quality assessment , pathology , business
Purpose: Dosimetric errors in radiotherapy dose delivery lead to suboptimal treatments and outcomes. This work reviews the frequency and severity of dosimetric and programmatic errors identified by on‐site audits performed by the IROC Houston QA center. Methods: IROC Houston on‐site audits evaluate absolute beam calibration, relative dosimetry data compared to the treatment planning system data, and processes such as machine QA. Audits conducted from 2000‐present were abstracted for recommendations, including type of recommendation and magnitude of error when applicable. Dosimetric recommendations corresponded to absolute dose errors >3% and relative dosimetry errors >2%. On‐site audits of 1020 accelerators at 409 institutions were reviewed. Results: A total of 1280 recommendations were made (average 3.1/institution). The most common recommendation was for inadequate QA procedures per TG‐40 and/or TG‐142 (82% of institutions) with the most commonly noted deficiency being x‐ray and electron off‐axis constancy versus gantry angle. Dosimetrically, the most common errors in relative dosimetry were in small‐field output factors (59% of institutions), wedge factors (33% of institutions), off‐axis factors (21% of institutions), and photon PDD (18% of institutions). Errors in calibration were also problematic: 20% of institutions had an error in electron beam calibration, 8% had an error in photon beam calibration, and 7% had an error in brachytherapy source calibration. Almost all types of data reviewed included errors up to 7% although 20 institutions had errors in excess of 10%, and 5 had errors in excess of 20%. The frequency of electron calibration errors decreased significantly with time, but all other errors show non‐significant changes. Conclusion: There are many common and often serious errors made during the establishment and maintenance of a radiotherapy program that can be identified through independent peer review. Physicists should be cautious, particularly in areas highlighted herein that show a tendency for errors.