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IMRT commissioning: Multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119
Author(s) -
Ezzell Gary A.,
Burmeister Jay W.,
Dogan Nesrin,
LoSasso Thomas J.,
Mechalakos James G.,
Mihailidis Dimitris,
Molineu Andrea,
Palta Jatinder R.,
Ramsey Chester R.,
Salter Bill J.,
Shi Jie,
Xia Ping,
Yue Ning J.,
Xiao Ying
Publication year - 2009
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 - 10.1118/1.3238104
Subject(s) - dosimetry , confidence interval , medical physics , imaging phantom , radiation treatment planning , nuclear medicine , radiological weapon , task group , medicine , mathematics , statistics , radiation therapy , radiology , engineering , engineering management
AAPM Task Group 119 has produced quantitative confidence limits as baseline expectation values for IMRT commissioning. A set of test cases was developed to assess the overall accuracy of planning and delivery of IMRT treatments. Each test uses contours of targets and avoidance structures drawn within rectangular phantoms. These tests were planned, delivered, measured, and analyzed by nine facilities using a variety of IMRT planning and delivery systems. Each facility had passed the Radiological Physics Center credentialing tests for IMRT. The agreement between the planned and measured doses was determined using ion chamber dosimetry in high and low dose regions, film dosimetry on coronal planes in the phantom with all fields delivered, and planar dosimetry for each field measured perpendicular to the central axis. The planar dose distributions were assessed using gamma criteria of 3%/3 mm. The mean values and standard deviations were used to develop confidence limits for the test results using the concept confidence limit = | mean | + 1.96 σ . Other facilities can use the test protocol and results as a basis for comparison to this group. Locally derived confidence limits that substantially exceed these baseline values may indicate the need for improved IMRT commissioning.