title: Reconstruction of biologically equivalent dose distribution on CT-image from measured physical dose distribution of therapeutic beam in water phantom.
abstract: From the standpoint of quality assurance in radiotherapy, it is very important to compare the dose distributions realized by an irradiation system with the distribution planned by a treatment planning system. To compare the two dose distributions, it is necessary to convert the dose distributions on CT images to distributions in a water phantom or convert the measured dose distributions to distributions on CT images. Especially in heavy-ion radiotherapy, it is reasonable to show the biologically equivalent dose distribution on the CT images. We developed tools for the visualization and comparison of these distributions in order to check the therapeutic beam for each patient at the National Institute of Radiological Sciences (NIRS). To estimate the distribution in a patient, the dose is derived from the measurement by mapping it on a CT-image. Fitting the depth-dose curve to the calculated SOBP curve also gives biologically equivalent dose distributions in the case of a carbon beam. Once calculated, dose distribution information can be easily handled to make a comparison with the planned distribution and display it on a grey-scale CT-image. Quantitative comparisons of dose distributions can be made with anatomical information, which also gives a verification of the irradiation system in a very straightforward way.
authors.affiliation: Research Center of Charged Particle Therapy, National Institute of Radiological Sciences, Inage, Chiba, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Mizota
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Kanai
authors.forename: Ken
authors.initials: K
authors.lastname: Yusa
authors.forename: Takashi
authors.initials: T
authors.lastname: Akagi
authors.forename: Munefumi
authors.initials: M
authors.lastname: Shimbo
authors.forename: Haruo
authors.initials: H
authors.lastname: Yamashita
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Futami
authors.forename: Masahiro
authors.initials: M
authors.lastname: Endo
mesh_terms: D006801:Humans; D015233:Models, Statistical; D019047:Phantoms, Imaging; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*