A physical dosimetry intercomparison for BNCT

Riley, Kent J.; Binns, Peter J.; Greenberg, D.; Harling, O. K.

doi:10.1118/1.1473133

Cited by 21 publications

(15 citation statements)

References 8 publications

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“…The Monte Carlo method simulates transport of neutrons and photons through the patient’s geometry and uses track-length density estimators of neutron and photon flux integrated against energy-dependent kerma coefficients to compute dose. Treatment planning systems require careful validation by evaluating agreement between dose calculations and in-phantom measurements [62,63]. Treatment planning calculations use individualized computational models of the target, constructed from CT or MR images.…”

Section: Boron Delivery Agentsmentioning

confidence: 99%

“…An extensive series of comparisons was performed between all clinical centers in the Americas and Europe [63,66-69] that found variations ranging between 7.6 and 13.2 Gy w for a common dose specification of 10 Gy w as defined in the Harvard-MIT clinical trials. The magnitude and range of these variations, illustrated in Figure 5 for several facilities, cannot be fully explained by experimental uncertainties or measurement errors.…”

Section: Boron Delivery Agentsmentioning

confidence: 99%

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Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

et al. 2012

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Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Clinical interest in BNCT has focused primarily on the treatment of high grade gliomas, recurrent cancers of the head and neck region and either primary or metastatic melanoma. Neutron sources for BNCT currently have been limited to specially modified nuclear reactors, which are or until the recent Japanese natural disaster, were available in Japan, the United States, Finland and several other European countries, Argentina and Taiwan. Accelerators producing epithermal neutron beams also could be used for BNCT and these are being developed in several countries. It is anticipated that the first Japanese accelerator will be available for therapeutic use in 2013. The major hurdle for the design and synthesis of boron delivery agents has been the requirement for selective tumor targeting to achieve boron concentrations in the range of 20 μg/g. This would be sufficient to deliver therapeutic doses of radiation with minimal normal tissue toxicity. Two boron drugs have been used clinically, a dihydroxyboryl derivative of phenylalanine, referred to as boronophenylalanine or “BPA”, and sodium borocaptate or “BSH” (Na2B12H11SH). In this report we will provide an overview of other boron delivery agents that currently are under evaluation, neutron sources in use or under development for BNCT, clinical dosimetry, treatment planning, and finally a summary of previous and on-going clinical studies for high grade gliomas and recurrent tumors of the head and neck region. Promising results have been obtained with both groups of patients but these outcomes must be more rigorously evaluated in larger, possibly randomized clinical trials. Finally, we will summarize the critical issues that must be addressed if BNCT is to become a more widely established clinical modality for the treatment of those malignancies for which there currently are no good treatment options.

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Section: Boron Delivery Agentsmentioning

confidence: 99%

Section: Boron Delivery Agentsmentioning

confidence: 99%

Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

et al. 2012

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“…Evaluation and comparison of treatment planning software is a critical step in the wider goal of standardization of dosimetry for NCT. Efforts to compare and standardize physical dosimetry in NCT have been formally initiated in the USA, 29 Europe, 30 and internationally. 31 As clinical trials of NCT progress, the benefits of standardized physical and computational dosimetry will permit the normalization of the dosimetry for subjects treated by NCT at different institutions and may eventually enable the legitimate pooling of such multisite clinical data.…”

Section: Introductionmentioning

confidence: 99%

Reference dosimetry calculations for neutron capture therapy with comparison of analytical and voxel models

2002

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As clinical trials of Neutron Capture Therapy (NCT) are initiated in the U.S. and other countries, new treatment planning codes are being developed to calculate detailed dose distributions in patient-specific models. The thorough evaluation and comparison of treatment planning codes is a critical step toward the eventual standardization of dosimetry, which, in turn, is an essential element for the rational comparison of clinical results from different institutions. In this paper we report development of a reference suite of computational test problems for NCT dosimetry and discuss common issues encountered in these calculations to facilitate quantitative evaluations and comparisons of NCT treatment planning codes. Specifically, detailed depth-kerma rate curves were calculated using the Monte Carlo radiation transport code MCNP4B for four different representations of the modified Snyder head phantom, an analytic, multishell, ellipsoidal model, and voxel representations of this model with cubic voxel sizes of 16, 8, and 4 mm. Monoenergetic and monodirectional beams of 0.0253 eV, 1, 2, 10, 100, and 1000 keV neutrons, and 0.2, 0.5, 1, 2, 5, and 10 MeV photons were individually simulated to calculate kerma rates to a statistical uncertainty of <1% (1 std. dev.) in the center of the head model. In addition, a "generic" epithermal neutron beam with a broad neutron spectrum, similar to epithermal beams currently used or proposed for NCT clinical trials, was computed for all models. The thermal neutron, fast neutron, and photon kerma rates calculated with the 4 and 8 mm voxel models were within 2% and 4%, respectively, of those calculated for the analytical model. The 16 mm voxel model produced unacceptably large discrepancies for all dose components. The effects from different kerma data sets and tissue compositions were evaluated. Updating the kerma data from ICRU 46 to ICRU 63 data produced less than 2% difference in kerma rate profiles. The depth-dose profile data, Monte Carlo code input, kerma factors, and model construction files are available electronically to aid in verifying new and existing NCT treatment planning codes.

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“…No such set of comparative data was available at the time of measurement. A comparison based only on the first set of measurements was presented previously, 14 and a physical dosimetry comparison between these two beams using conventional methods has since been published by Riley et al 15 The intercomparison phantom is a 14ϫ14 ϫ14 cm 3 acrylic cube which is identical to the BNL ''home'' phantom. The ''home'' phantom at MIT is an ellipsoidal head phantom, consisting of a 20ϫ17ϫ14 cm 3 acrylic shell filled with distilled water.…”

Section: Methodsmentioning

confidence: 99%

Microdosimetric intercomparison of BNCT beams at BNL and MIT

et al. 2003

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Microdosimetric measurements have been performed at the clinical beam intensities in two epithermal neutron beams, the Brookhaven Medical Research Reactor and the M67 beam at the Massachusetts Institute of Technology Research Reactor, which have been used to treat patients with Boron Neutron Capture Therapy (BNCT). These measurements offer an independent assessment of the dosimetry used at these two facilities, as well as provide information about the radiation quality not obtainable from conventional macrodosimetric techniques. Moreover, they provide a direct measurement of the absorbed dose resulting from the BNC reaction. BNC absorbed doses measured within this study are approximately 15% lower than those estimated using foil activation at both MIT and BNL. Finally, an intercomparison of the characteristics and radiation quality of these two clinical beams is presented. The techniques described here allow an accurate quantitative comparison of the physical absorbed dose as well as a measure of the biological effectiveness of the absorbed dose delivered by different epithermal beams. No statistically significant differences were observed in the predicted RBEs of these two beams. The methodology presented here can help to facilitate the effective sharing of clinical results in an effort to demonstrate the clinical utility of BNCT.

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A physical dosimetry intercomparison for BNCT

Cited by 21 publications

References 8 publications

Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

Reference dosimetry calculations for neutron capture therapy with comparison of analytical and voxel models

Microdosimetric intercomparison of BNCT beams at BNL and MIT

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