Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon beams.
An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of ND,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.
National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada.
Malcolm
M
McEwen
University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705.
Larry
L
DeWerd
Department of Radiation Physics, M D Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030.
Geoffrey
G
Ibbott
IROC Houston QA Center, Radiological Physics Center, 8060 El Rio Street, Houston, Texas 77054.
David
D
Followill
Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada.
David W O
DW
Rogers
National Institute of Standards and Technology, Gaithersburg, Maryland 20899.
Stephen
S
Seltzer
Medical Physics Unit, McGill University, 1650 Cedar Avenue, Montreal, Québec, Canada.
Jan
J
Seuntjens
D002138:Calibration; D006801:Humans; D009010:Monte Carlo Method; D017785:Photons / Q000627:therapeutic use*; D017410:Practice Guidelines as Topic; D011874:Radiometry / Q000592:standards*; D012958:Societies, Scientific; D035501:Uncertainty