Reference dosimetry in the presence of magnetic fields: conditions to validate Monte Carlo simulations.
With the advent of MRI-guided radiotherapy, reference dosimetry must be thoroughly addressed to account for the effects of the magnetic field on absorbed dose to water and on detector dose response. While Monte Carlo plays an essential role in reference dosimetry, it is also crucial for determining quality correction factors in these new conditions. The Fano cavity test is recognized as fundamental to validate Monte Carlo transport algorithms. In the presence of magnetic fields, it is necessary to define special conditions under which such a test can be performed. The present theoretical study proposes two conditions in which the validity of Fano's theorem is demonstrated in the presence of a magnetic field and the analytic expression of energy deposition is verified. It is concluded that the proposed conditions form a valid basis for two types of Fano cavity tests in the presence of a magnetic field.
Acoustics and Ionising Radiation Team, National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
Hugo
H
Bouchard
Jacco
J
de Pooter
Alex
A
Bielajew
Simon
S
Duane
D000465:Algorithms; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging; D009010:Monte Carlo Method; D011874:Radiometry / Q000592:standards*; D061089:Radiotherapy, Image-Guided; D012016:Reference Values