A Comprehensive PC-based Computer Model for Microdosimetry of BNCT

Verrijk, R.; Huiskamp, R.; Begg, Adrian C.; Wheeler, Floyd J.; Watkins, P.

doi:10.1080/09553009414550271

Cited by 14 publications

(6 citation statements)

References 35 publications

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“…3. There was a good match for calculated survival values S tot in comparison with measured values from Gabel et al [22] and with the calculated D 0 value from Verrijk et al [17]. The same parameter for computer calculations, as given in Table 1, Table 2 for the V79 cell suspension.…”

Section: Resultsmentioning

confidence: 81%

“…3 Comparison between measured (ć) and calculated (í) survival data for V79 cells after BNC irradiation in suspension with the BMRR thermal neutron beam. The measured values are from Gabel et al [34], and the calculated value (b) is from Verrijk et al [17]. Table 2), about 10% of the dose D B would be expected to come from external 10 B, while about 40% of the dose would come from 10 B in the cytoplasm and about 50% from the cell nucleus.…”

Section: Discussionmentioning

confidence: 99%

“…A computer model has recently been developed by Verrijk et al [17] which uses RBE values of alpha-particles measured at different LETs [12] and the measured x-ray survival curve of cells in order to estimate high-LET radiation effects caused by boron neutron capture. In this model, a microscopic efficacy factor was calculated for each individual particle track segment that traverses the cell nucleus, including the effect of cross-fire from particles produced in adjacent cells, which makes the program suitable for densely packed cell structures.…”

Section: Introductionmentioning

confidence: 99%

“…Several Monte-Carlo models for microdosimetry have been developed in order to calculate mean absorbed doses to the cell nuclei for BNCT [13][14][15][16][17]. In these models, single mean RBEs were used to transform high-LET radiation doses into low-LET photon doses for the same biological endpoint.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Calculation of boron neutron capture cell inactivation in vitro based on particle track structure and x-ray sensitivity

Pöller

Wittig

Sauerwein

1998

Radiation and Environmental Biophysics

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The Monte-Carlo technique was used to perform quantitative microdosimetric model calculations of cell survival after boron neutron capture irradiations in vitro. The high energy 7Li and alpha-particles resulting from the neutron capture reaction 10B (n,alpha)7Li are of short range and are highly damaging to cells. The biophysical model of the Monte-Carlo calculations is based on the track structure of these a-particles and 7Li-ions and the x-ray sensitivity of the irradiated cells. The biological effect of these particles can be determined if the lethal effect of local doses deposited in very small fractional volumes of the cell nucleus is known. This lethal effect can be deduced from experimental data of cell survival after x-ray irradiation assuming a Poisson distribution for lethal events. The input data used in a PC-based computer program are the radial dose distribution inside the track of the released particles, cell survival after x-ray irradiation, geometry of the tumor cells, subcellular 10B concentration, and thermal neutron fluence. The basic concept of this Monte-Carlo computer model is demonstrated. Validations of computer calculations are presented by comparing them with experimental data on cell survival.

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Section: Resultsmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calculation of boron neutron capture cell inactivation in vitro based on particle track structure and x-ray sensitivity

Pöller

Wittig

Sauerwein

1998

Radiation and Environmental Biophysics

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“…Theoretical radiation dose calculation Boron-related physical radiation dose rates were calculated with a three-dimensional microdosimetry PC-based computer programm, previously described by us (Verrijk et al, 1994). Briefly, energy deposition of boron neutron capture products, alpha particles and lithium ions were cumulatively recorded in a spherical nucleus modelled in a cuboidal cell.…”

Section: Drugsmentioning

confidence: 99%

Pharmacokinetics in melanoma-bearing mice of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a candidate compound for boron neutron capture therapy

Verrijk

Smolders²,

Huiskamp³

et al. 1994

Br J Cancer

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Summary Blood pharmacokinetics and tissue distribution of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a boron carrier with postulated melanin-seeking properties for boron neutron capture therapy, were determined in C57/BL mice with subcutaneous pigmented or non-pigmented B16 melanomas. Borocaptate sodium (BSH) was used as a boron compound without melanin-seeking properties in a comparative biodistribution study in the same animal tumour models. Administration of single doses showed that BPTU was retained better in the pigmented B16 tumour than in the non-pigmented variant. BPTU was found in large concentrations in kidney and liver. Brain boron was approximately 10-fold lower than tumour boron. On a molar basis, BPTU demonstrated higher affinity for B16 tumours than BSH. Owing to solubility limits, tumour boron concentrations in this mouse study were too low for effective application of BNCT. However, the high tumour-to-blood and tumour-to-normal tissues ratios indicate that, with appropriate formulation, BPTU could be a promising candidate for clinical BNCT.The primary goal of boron neutron capture therapy (BNCT) at the present time is to achieve more effective treatments for glioma and melanoma than conventional radiotherapy (Allen et al., 1989;Slatkin, 1991). The selective accumulation of "'B-containing compounds in tumours and subsequent irradiation with low-energy (thermal) neutrons form the basis of BNCT. The short track lengths of`'B(n,a)7Li fission products (9 and 5 iLm for a and 7Li respectively) offer partial restriction of the radiation dose to the "'B-containing cells. Additional advantages owing to the high-LET (linear energy transfer) character of the emitted radiation are higher biological efficacies compared with photons or X-rays and less effect of hypoxia or cell cycle distribution on the therapeutic effect. The relatively high resistance of melanomas for photon therapy and the presence of a biochemical rationale for boron targeting explain the efforts made in this area Madoc Jones et al., 1990). The often high rate of melanogenesis in melanoma cells has led to the development of several boron drugs with melanoma-seeking capacity.The L-isomer of boronphenylalanine (BPA) is taken up by melanoma cells both in vitro and in vivo (Ichihashi et al., 1982; Coderre et al., 1987;Allen et al., 1992;Packer et al., 1992). Animal studies on BNCT efficacy and normal tissue tolerance with BPA have also been performed (Coderre et al., 1991; Hiratsuka et al., 1991). Although the uptake of BPA in melanoma cells is well accepted, incorporation of boron into melanin might not occur, resulting in poor retention. Boronated thiouracils that enter the melanogenesis pathway at a different point from BPA have been recently synthesised, aiming at boron incorporation into the melanin for better retention (Tjarks & Gabel, 1991). We have found previously that 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU) and not boronthiouracil (BTU) was retained in vitro in melanotic B16 cells, while BPTU failed to be retained in th...

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Modeling the Impact of Near-Threshold 7Li(p,n)7Be Generated, Fast Neutron Beams on Boron Drug Distribution Requirements for BNCT

LaHann

Griebenow

Larsen

2001

Frontiers in Neutron Capture Therapy

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A Comprehensive PC-based Computer Model for Microdosimetry of BNCT

Cited by 14 publications

References 35 publications

Calculation of boron neutron capture cell inactivation in vitro based on particle track structure and x-ray sensitivity

Calculation of boron neutron capture cell inactivation in vitro based on particle track structure and x-ray sensitivity

Pharmacokinetics in melanoma-bearing mice of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a candidate compound for boron neutron capture therapy

Modeling the Impact of Near-Threshold 7Li(p,n)7Be Generated, Fast Neutron Beams on Boron Drug Distribution Requirements for BNCT

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