TY - JOUR
T1 - Dependences of mucosal dose on photon beams in head-and-neck intensity-modulated radiation therapy
T2 - A Monte Carlo study
AU - Chow, James C.L.
AU - Owrangi, Amir M.
N1 - Funding Information:
Measurements related to the Monte Carlo validation were carried out in the Grand River Hospital. J.C.L.C would like to thank Varti Vartanian and Mitch Spiegel of Varian Medical Systems for providing detailed information of the Varian 21 EX linear accelerator. This study was supported by the Dean's Fund Grant in the University of Toronto .
PY - 2012
Y1 - 2012
N2 - Dependences of mucosal dose in the oral or nasal cavity on the beam energy, beam angle, multibeam configuration, and mucosal thickness were studied for small photon fields using Monte Carlo simulations (EGSnrc-based code), which were validated by measurements. Cylindrical mucosa phantoms (mucosal thickness = 1, 2, and 3 mm) with and without the bone and air inhomogeneities were irradiated by the 6- and 18-MV photon beams (field size = 1 × 1 cm 2) with gantry angles equal to 0°, 90°, and 180°, and multibeam configurations using 2, 4, and 8 photon beams in different orientations around the phantom. Doses along the central beam axis in the mucosal tissue were calculated. The mucosal surface doses were found to decrease slightly (1% for the 6-MV photon beam and 3% for the 18-MV beam) with an increase of mucosal thickness from 1-3 mm, when the beam angle is 0°. The variation of mucosal surface dose with its thickness became insignificant when the beam angle was changed to 180°, but the dose at the bone-mucosa interface was found to increase (28% for the 6-MV photon beam and 20% for the 18-MV beam) with the mucosal thickness. For different multibeam configurations, the dependence of mucosal dose on its thickness became insignificant when the number of photon beams around the mucosal tissue was increased. The mucosal dose with bone was varied with the beam energy, beam angle, multibeam configuration and mucosal thickness for a small segmental photon field. These dosimetric variations are important to consider improving the treatment strategy, so the mucosal complications in head-and-neck intensity-modulated radiation therapy can be minimized.
AB - Dependences of mucosal dose in the oral or nasal cavity on the beam energy, beam angle, multibeam configuration, and mucosal thickness were studied for small photon fields using Monte Carlo simulations (EGSnrc-based code), which were validated by measurements. Cylindrical mucosa phantoms (mucosal thickness = 1, 2, and 3 mm) with and without the bone and air inhomogeneities were irradiated by the 6- and 18-MV photon beams (field size = 1 × 1 cm 2) with gantry angles equal to 0°, 90°, and 180°, and multibeam configurations using 2, 4, and 8 photon beams in different orientations around the phantom. Doses along the central beam axis in the mucosal tissue were calculated. The mucosal surface doses were found to decrease slightly (1% for the 6-MV photon beam and 3% for the 18-MV beam) with an increase of mucosal thickness from 1-3 mm, when the beam angle is 0°. The variation of mucosal surface dose with its thickness became insignificant when the beam angle was changed to 180°, but the dose at the bone-mucosa interface was found to increase (28% for the 6-MV photon beam and 20% for the 18-MV beam) with the mucosal thickness. For different multibeam configurations, the dependence of mucosal dose on its thickness became insignificant when the number of photon beams around the mucosal tissue was increased. The mucosal dose with bone was varied with the beam energy, beam angle, multibeam configuration and mucosal thickness for a small segmental photon field. These dosimetric variations are important to consider improving the treatment strategy, so the mucosal complications in head-and-neck intensity-modulated radiation therapy can be minimized.
KW - Head-and-neck IMRT
KW - Inhomogeneities
KW - Monte Carlo
KW - Mucosal dose
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U2 - 10.1016/j.meddos.2011.07.002
DO - 10.1016/j.meddos.2011.07.002
M3 - Article
C2 - 21993201
AN - SCOPUS:84860466978
SN - 0958-3947
VL - 37
SP - 195
EP - 200
JO - Medical Dosimetry
JF - Medical Dosimetry
IS - 2
ER -