title: Cluster models in cellular level electron dose calculations.
abstract: A program for calculating absorbed dose was developed for radioimmunotherapy (RIT) purposes. It was used to determine the difference in the therapeutic effect of (111)In electrons when using a close-packed cubic geometry and a cell cluster model developed in this project. Our cluster model piles the cells individually. The cells were modelled as spheres of diameters of 12 (tumour) and 30 (healthy) microm. Both models were used to generate clusters with spherical tumours inside healthy tissue. The program uses Monte Carlo-based dose kernels. The radiation spectra were calculated from the Auger and x-ray transition strengths and fluorescence yields of (111)In. The results show the importance of the cluster model in cellular level dose calculations. Near the tumour/healthy tissue interface in particular, the doses differ because of geometrical differences. In the case of a small cluster with tumour and total diameters of 30 and 150 microm, the ratio of the therapeutic effects is 20.
authors.affiliation: Department of Physics, University of Helsinki, and Helsinki University Central Hospital, Finland. Juha.Lampinen@Helsinki.fi
authors.forename: J S
authors.initials: JS
authors.lastname: Lampinen
authors.forename: P J
authors.initials: PJ
authors.lastname: Välimäki
authors.forename: A A
authors.initials: AA
authors.lastname: Kuronen
authors.forename: J
authors.initials: J
authors.lastname: Stepanek
authors.forename: S E
authors.initials: SE
authors.lastname: Savolainen
mesh_terms: D000042:Absorption; D002477:Cells / Q000528:radiation effects*; D016000:Cluster Analysis; D004583:Electrons; D006801:Humans; D007205:Indium Radioisotopes / Q000627:therapeutic use; D009010:Monte Carlo Method; D016499:Radioimmunotherapy; D011874:Radiometry; D014407:Tumor Cells, Cultured
chemical_list: D007205:Indium Radioisotopes