[en] This article presents a survey of recent progress in the development and application of analytical methods for calculating macroscopic and microscopic radiation dose distributions for Boron Neutron Capture Therapy (BNCT). Such calculations are an essential component of in vivo BNCT research and will ultimately also be required for human BNCT treatment planning. Calculations of macroscopic absorbed dose distributions for BNCT are more complex than for photon therapy. There are several different dose components, each of which has its own characteristic spatial distribution, linear energy transfer, and relative biological effectiveness (RBE). Three-dimensional (3-D) energy-dependent radiation transport models with a detailed treatment of particle scattering are required. Geometric descriptions for such models are typically constructed directly from medical image data and both the Monte Carlo stochastic simulation method and the discrete-ordinates deterministic approach have been successfully used to perform the necessary radiation transport calculations. Microdosimetric effects can profoundly influence the therapeutic benefit that may be attainable in BNCT. These effects must be carefully taken into account in the interpretation dose. Calculations of microdosimetric parameters for BNCT are typically performed using the Monte Carlo method to generate single-event energy deposition frequency distributions for critical targets in various cell types of interest. This information is useful in the development of apparent RBE factors, or open-quotes compound factorsclose quotes for the various dose components in BNCT. 31 refs., 15 figs., 1 tab

[en] Calculation of radiation dose distributions for Boron Neutron Capture Therapy (BNCT) is an essential supporting function for in vivo BNCT radiobiological research. Such calculations will also ultimately be routinely required for human treatment planning. Radiation transport and dose distribution analysis for BNCT is much more complex than is the case for standard photon therapy. There are several different physical radiation dose components associated with BNCT, each of which has it's own characteristic spatial distribution and Relative Biological Effectiveness (RBE). Most of these radiation dose components result from neutron interactions that take place after the incident neutrons from the treatment beam have undergone several scattering interactions. Accordingly, many of the simplifying assumptions that work well for radiation transport calculations associated with treatment planning for standard photon therapy are not appropriate for BNCT. Full three-dimensional calculations with an explicit treatment of particle scattering and tissue heterogeneities are required

[en] The authors have developed a direct enantioselective synthesis of L-BPA utilizing the asymmetric hydrogenation of a prochiral olefin using a chiral 1,2-diphosphine complex of rhodium. The optimal diphosphine (called DIPAMP) is not commercially available, so in the research they screened those diphosphines that are available for their ability to induce chirality in the reduction of the substrate. The ligand called R-Prophos, originally developed by Bosnich, was found to be adequate for the large-scale preparation of L-BPA, described below. The use of cationic rhodium diphosphine complex in catalytic hydrogenations is well established. To their knowledge, however this is the first example in which a boronic acid group has been present on the olefin, and it is well tolerated by the catalyst. The methodology described here should be adaptable to the synthesis of other α-amino acids containing this functionality. Moreover, the tolerance for this group suggests that other boron-containing moieties, such as carboranes or closoborane dianions, could also be tolerated

[en] This invention relates to a system for use in Boron Neutron Capture Therapy (BNCT) radiotherapy planning where a biological distribution is calculated using a combination of conversion factors and a previously calculated physical distribution. Conversion factors are presented in a graphical spreadsheet so that a planner can easily view and modify the conversion factors. For radiotherapy in multi-component modalities, such as fast-neutron and BNCT, it is necessary to combine each conversion factor component to form an effective dose which is used in radiotherapy planning and evaluation. The dose factor entry and display system is designed to facilitate planner entry of appropriate conversion factors in a straightforward manner for each component. The effective isodose is then immediately computed and displayed over the appropriate background (e.g. digitized image)

[en] Published in summary form only

[en] It is now obvious that all cancers should not be treated with an identical dose fractionation regimen but the authors do not have the necessary technology to predict the best option for an individual patient. The best average option is still a matter of discussion but it seems likely that for an average tumor the best average treatment would involve the smallest dose per fraction given sufficiently often with interfraction intervals adequate to permit complete repair of sublethal damage but with the overall treatment given in the shortest time tolerated by the acutely responding normal tissues. In general, this principle would apply to BNCT. For BNCT the choice of an optimal dose fractionation regimen is likely to be far more complex that it is for x-rays. Development of BNCT has an advantage over the development of x-ray therapy in that the basic phenomena influencing tissues responses to fractionated irradiation are now much better understood than even ten years ago

[en] Biologically targeted radiotherapy entails the preferential delivery of radiation to solid tumours or individual tumour cells by means of tumour-seeking delivery vehicles to which radionuclides can be conjugated. Monoclonal antibodies have attracted attention for some years as potentially selective targeting agents, but advances in tumour and molecular biology are now providing a much wider choice of molecular species. General radiobiological principles may be derived which are applicable to most forms of targeted radiotherapy. These principles provide guidelines for the appropriate choice of radionuclide in specific treatment situations and its optimal combination with other treatment modalities. In future, the availability of gene targeting agents will focus attention on the use of Auger electron emitters whose high potency and short range selectivity makes them attractive choices for specific killing of cancer cells whose genetic peculiarities are known. (author)

[en] This paper describes the written procedures adopted by the Massachusetts Institute of TEchnology (MIT) and the New England Medical Center (NEMC) to implement their neutron capture therapy program. The procedures are sufficiently flexible enough to accommodate the differing needs of each patient. Twenty eight procedures were prepared to implement the program

[en] The effect of substructural features of boron compounds on their toxicity (LD₅₀, mice, i.p.) was studied using the FEL-EXPERT system developed by the Czech Technical University of Prague. A set of 108 compounds containing one or two boron atoms in their molecule was arbitrarily divided into three classes: compounds with high toxicity (LD₅₀<100 mg/kg), with medium toxicity (100 mg/kg≤LD₅₀<1000 mg/kg) and with low toxicity (LD₅₀≥1000 mg/kg). The compounds were represented by 70 substructural fragments, 27 of them being ''central substructures'' containing boron atom(s). The inference net consisted of 118 nodes (74 of the Bayesian type), 362 production rules and 74 context links. The total classification correctness was 98%. As a case-study, the classification of p-tolylboronic acid (LD₅₀=520 mg/kg) and 4-carboxyphenylboronic acid (LD₅₀=3838 mg/kg) was discussed. 4 figs., 2 tabs., 11 refs

[en] Imidocaptate (IC) was developed for experimental boron neutron capture therapy for cancer. Electrospray ionization mass spectrometry (ESI-MS) was used to characterize the IC by using various counter ion pairs. The best results were obtained with ion paired with triethylamine, and tetraethylammonium cations