[Use experience and problems in the optimization of intensity modulated radiation therapy (IMRT)--Focus on head & neck].
We present the main points of the optimization in IMRT. The skin surface of the planned target volume was reduced by a few millimeters, in view of the limitations of a calculation grid in accurately estimating the influence of build-up or contamination of electrons. Air cavities such as nasal or oral cavities were, in general, filled with water equivalent density in the dose calculation. Planned target volume was contracted by 5 mm when PTV of a higher prescribed dose was delineated adjacent to it. The 5 mm width of ring-shaped ROI was set at 5 mm outside of the entire PTV to eliminate hot spots. Physical quality assurance is extremely important to eradicate unexpected dose inhomogeneity, and meticulous efforts are required.
Ariji
Takaki
T
Department of radiology, National Canser Center Hospital East.
Ueda
Takashi
T
Kitoh
Satoshi
S
Goka
Tomonori
T
Kameoka
Satoru
S
Kohno
Ryosuke
R
Nishio
Teiji
T
Kawashima
Mitsuhiko
M
D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*