Dosimetry on sub-cellular level for intracellular incorporated auger-electron-emitting radionuclides: a comparison of Monte Carlo simulations and analytic calculations

Abstract

A quantitative dosimetric comparison was performed between Monte Carlo (MC) simulations and analytic calculations at the (sub) cellular level (V79 cells) for four nucleus-incorporated radiochemicals ((125)I/(123)I/(77)Br-UdR and A (125)IP) and two radiochemicals that localised mainly in the cytoplasm of cells ((125)I-dihydrorhodamine and Na(2)(51)CrO(4)). A microscopic investigation around the decay site of the three DNA-incorporated radionuclides ((125)I/(123)I/(77)Br-UdR) was also carried out. On the whole, deviations between MC and analytic calculations for the absorbed dose and dose rate to the cell nucleus were within ∼10%. The dose rate to the nucleus for the radiochemicals that mainly localised in the cytoplasm was greater than that for the nucleus-incorporated ones. Also evident was that the dose rate to the nucleus was approximately the same for the three DNA-incorporated radiochemicals. In contrast to the small differences found between MC and analytic calculations for the (average) absorbed dose to the nucleus, the dosimetric analysis at the microscopic level for the three DNA-incorporated radionuclides showed that the two computational approaches lead to a completely different energy deposition pattern around the decay site.

Monte Carlo single-cell dosimetry of I-131, I-125 and I-123 for targeted radioimmunotherapy of B-cell lymphoma

“…Regarding 125 I and 123 I, an extensive dosimetric comparison between our MC simulations with those of previous studies at the cellular level was undertaken in our previous works (Bousis et al 2010, Bousis 2011. For a uniform distribution of radioactivity throughout the examined spherical volumes, our results were in good agreement with those of previous studies with difference being less than 10%.…”

Production and dosimetric aspects of the potent Auger emitter 58mCo for targeted radionuclide therapy of small tumors

“…Several studies have compared the results obtained with this method and Monte Carlo (MC) calculation and have found good agreements at the cellular scale (1-10 lm)-but not at the DNA-scale. [29][30][31] Ftacniková et al 32 have found excellent agreement between the S-values (S(N/N), S(N/Cy), S(N/CS)) obtained with either MC calculations, Berger's ETRAN data, or MIRDs method (Cole) and the authors concluded that time-consuming MC calculations are not necessary at the cellular scale. In MIRD Cellular S-values Goddu et al 17 also found excellent agreement (<10%) between MC calculations of S(N/N) and their method for electron energies less than several hundred keV.…”

Calculation of cellular S-values using Geant4-DNA: The effect of cell geometry

“…Specifically, differences between the convolution integral and the Monte Carlo results were up to 50% for the largest sphere (radius 1 μm), increasing further for smaller spheres. Bousis et al (Bousis, 2011;Bousis et al, 2012Bousis et al, , 2010 have tabulated cellular S-values using their home-made Monte Carlo code (MC4) for various Auger-emitting radionuclides, reporting good agreement ( $ 10%) with MIRD for S(C'C), S (C'CS) and S(N'N) but poor agreement ( $ 50%) for S(N'Cy) and S(N'CS) (C: cell, CS: cell surface, N: nucleus, Cy: cytoplasm). Champion et al (2008) used the Monte Carlo code CELLDOSE to calculate S-values in water spheres with radius from 50 nm to 2.5 mm for I-131.…”