A CT calibration method based on the polybinary tissue model for radiotherapy treatment planning.
A method to establish the relationship between CT number and effective density for therapeutic radiations is proposed. We approximated body tissues to mixtures of muscle, air, fat and bone. Consequently, the relationship can be calibrated only with a CT scan of their substitutes, for which we chose water, air, ethanol and potassium phosphate solution, respectively. With simple and specific corrections for non-equivalencies of the substitutes, a calibration accuracy of 1% will be achieved. We tested the calibration method with some biological materials to verify that the proposed method would offer the accuracy, simplicity and specificity required for a standard in radiotherapy treatment planning, in particular with heavy charged particles.
Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan. nkanemat@nirs.go.jp
Nobuyuki
N
Kanematsu
Naruhiro
N
Matsufuji
Ryosuke
R
Kohno
Shinichi
S
Minohara
Tatsuaki
T
Kanai
D000273:Adipose Tissue / Q000502:physiology; D000818:Animals; D001842:Bone and Bones / Q000502:physiology*; D002138:Calibration / Q000592:standards; D003198:Computer Simulation; D006801:Humans; D008460:Meat; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D019047:Phantoms, Imaging / Q000592:standards*; D011874:Radiometry / Q000379:methods* / Q000592:standards*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards*; D012015:Reference Standards