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- Hindorf, Cecilia, et al.
(författare)
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Single-cell dosimetry for radioimmunotherapy of B-cell lymphoma patients with special reference to leukemic spread
- 2007
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 22:3, s. 357-366
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Many lymphoma patients have both macroscopic tumors and single-cell manifestations of their disease. Treatment efficacy could, therefore, depend on the radionuclide used. The aim of this study was to investigate dosimetry at a cellular level for three isotopes of radioiodine. Methods: Cells were assumed to be spherical with radii of 6.35, 7.7, and 9.05 mu m corresponding to the dimensions of the Raji cells. The radius of the nucleus was assumed to be 75% of the cellular radius. The electron energies were 18, 28, and 190 keV, corresponding to the mean electron energy per decay for I-125, I-123, and I-131, respectively. S-values for different activity distributions were simulated using Monte Carlo and dose-volume histograms as well as absorbed doses, and absorbed dose rates were calculated. Results: I-125 gives the highest absorbed dose (similar to 4-40 times that of I-131), whereas I-123 Will give the highest absorbed dose rate (similar to 100 times that of I-131). Under the given assumptions, the absorbed dose at this level is more dependent on the Size of the cells than on whether the radioimmunoconjugate is internalized. Conclusions: This enquiry showed that both I-123 and I-125 have greater potential than I-131 for the treatment of leukemic spread in patients With lymphoma.
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- Liamsuwan, Thiansin, et al.
(författare)
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A model of carbon ion interactions in water using the classical trajectory Monte Carlo method
- 2011
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Ingår i: International Journal of Radiation Biology. - : Oxford University Press (OUP). - 0955-3002 .- 1362-3095. ; 143:2-4, s. 152-155
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, model calculations for interactions of C6+ of energies from 1 keV u−1 to 1 MeV u−1 in water are presented. The calculations were carried out using the classical trajectory Monte Carlo method, taking into account the dynamic screening of the target core. The total cross sections (TCS) for electron capture and ionisation, and the singly and doubly differential cross sections (SDCS and DDCS) for ionisation were calculated for the five potential energy levels of the water molecule. The peaks in the DDCS for the electron capture to continuum and for the binary-encounter collision were obtained for 500-keV u−1 carbon ions. The calculated SDCS agree reasonably well with the z2 scaled proton data for 500 keV u−1 and 1 MeV u−1 projectiles, but a large deviation of up to 8-folds was observed for 100-keV u−1 projectiles. The TCS for ionisation are in agreement with the values calculated from the first born approximation (FBA) at the highest energy region investigated, but become smaller than the values from the FBA at the lower-energy region.
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- Liamsuwan, Thiansin, 1984-, et al.
(författare)
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Physical and biophysical properties of proton tracks of energies 1 keV to 300 MeV in water
- 2011
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 87:2, s. 141-160
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Tidskriftsartikel (refereegranskat)abstract
- Materials and methods: aEuro integral We present model calculations for cross sections and methods for simulations of full-slowing-down proton tracks. Protons and electrons were followed interaction-by-interaction to cut-off energies, considering elastic scattering, ionisation, excitation, and charge-transfer. Results: aEuro integral Model calculations are presented for singly differential and total cross sections, and path lengths and stopping powers as a measure of the code evaluation. Depth-dose distributions for 160 MeV protons are compared with experimental data. Frequencies of energy loss by electron interactions increase from similar to 3%% for 10 keV to similar to 77%% for 300 MeV protons, and electrons deposit aEuroS > 70%% of the dose in 160 MeV tracks. From microdosimetry calculations, 1 MeV protons were found to be more effective than 5--300 MeV in energy depositions greater than 25, 50, and 500 eV in cylinders of diameters and lengths 2, 10, and 100 nm, respectively. For lower-energy depositions, higher-energy protons are more effective. Decreasing the target size leads to the reduction of frequency- and dose-mean lineal energies for protons < 1 MeV, and conversely for higher-energy protons. Conclusions: aEuro integral Descriptions of proton tracks at molecular levels facilitate investigations of track properties, energy loss, and microdosimetric parameters for radiation biophysics, radiation therapy, and space radiation research.
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