Kumada, Hiroaki; Yamamoto, Kazuyoshi; Yamamoto, Tetsuya*; Nakai, Kei*; Nakagawa, Yoshinobu*; Kageji, Teruyoshi*; Matsumura, Akira*
Applied Radiation and Isotopes, 61(5), p.1045 - 1050, 2004/11
To carry out the BNCT clinical trials based on accurate dosimetry of several absorbed doses given to a patient, we have developed JCDS which can determine the absorbed doses by numerical simulation. The aim of this study is to improve the accuracy of the BNCT dosimetry efficiently. We have developed the multi-voxel calculation method reconstructing the original voxel model by combining of several voxel cell sizes such as in 5mm, 10mm and 20mm voxel cell. To verify the accuracy of the multi-voxel method, the calculation results were compared with the phantom experimental data. These results proved that the multi-voxel calculation enables JCDS to more accurately estimate the absorbed doses to a patient by efficient calculations.
Kageji, Teruyoshi*; Nagahiro, Shinji*; Mizobuchi, Keiji*; Toi, Hiroyuki*; Nakagawa, Yoshinobu*; Kumada, Hiroaki
Applied Radiation and Isotopes, 61(5), p.1063 - 1067, 2004/11
no abstracts in English
Yamamoto, Tetsuya*; Matsumura, Akira*; Nakai, Kei*; Shibata, Yasushi*; Endo, Kiyoshi*; Sakurai, Fumio; Kishi, Toshiaki; Kumada, Hiroaki; Yamamoto, Kazuyoshi; Torii, Yoshiya
Applied Radiation and Isotopes, 61(5), p.1089 - 1093, 2004/11
no abstracts in English
Yamamoto, Kazuyoshi; Kumada, Hiroaki; Nakai, Kei*; Endo, Kiyoshi*; Yamamoto, Tetsuya*; Matsumura, Akira*
Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 14 Pages, 2004/10
A dose distribution considered the tumor cell density distribution is required on the radiation therapy. We propose a novel method of determining target region considering the tumor cell concentration as a new function for the next generation Boron Neutron Capture Therapy (BNCT) dosimetry system. It has not been able to sufficiently define the degree of microscopic diffuse invasion of the tumor cells peripheral to a tumor bulk in malignant glioma using current medical imaging. Referring to treatment protocol of BNCT, the target region surrounding the tumor bulk has been set as the region which expands at the optional distance with usual 2cm margin from the region enhanced on T1 weighted gadolinium Magnetic Resonance Imaging (MRI). In this research, the cell concentration of the region boundary of the target was discussed by using tumor cell diffusion model in the sphere spatio-temporal system. The survival tumor cell density distribution after the BNCT irradiation was predicted by the two regions diffusion model for a virtual brain phantom.
Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Torii, Yoshiya; Sakurai, Yoshinori*; Kobayashi, Toru*
Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 15 Pages, 2004/10
To carry out the boron neutron capture therapy (BNCT) using the epithermal neutron, the epithermal neutron beam intensity was measured by using Au reaction rate activated on the resonance absorption peak (4.9eV). Two scaling factors, which are the reactor power calibration factor and the calculation/experiment (C/E) scaling factor, are necessary in order to correct with the simulation and actual irradiation experiment. First, an optimum detector position was investigated using MCNP code. The result of MCNP calculation showed that the influence of subject placed at the collimator was below 1% when the detector was placed in the distance of over 20cm from the collimator. Therefore we installed the monitor holders near the bismuth block in order to set three gold wire monitors. The factors were determined in the calibration experiments that measure the thermal neutron flux in the phantom and reaction rate of the gold wire monitors. The monitoring technique to measure epithermal neutron beam intensity was applied to clinical irradiation with the epithermal neutron beam.
Takahashi, Kazunori*; Nakamura, Hiroyuki*; Furumoto, Shozo*; Yamamoto, Kazuyoshi; Matsumura, Akira*; Fukuda, Hiroshi*; Yamamoto, Yoshinori*
Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 1 Pages, 2004/10
We synthesized a BPA-Gd-DTPA compound, as a carrier for neutron capture therapy to be used for MRI contrast media. Pinanediol was used as the protective group for B(OH)2 group of BPA, and the BPA unit was connected to the DTPA framework through an amide bond. The biodistribution studies were performed after injection of the compound into AH109A hepatoma bearing Donryu rats. The concentrations of Gd and boron were measured by prompt g-ray analyses. The tumor uptakes (% ID/g) were 1% and 0.3% at 20 min and 60 min after injection, respectively and were higher than that of carborane-Gd-DTPA, which we previously reported. However, liver and kidney uptake was very high and tumor/blood ratio was very low (0.38) compared to that of BPA itself (ca. 3.0). Alfa autoradiogram of a tumor bearing rat showed higher concentration of boron in the tumor compared to surrounding muscle and very high in the intestine. Although tumor selectivity of the compound was higher than that of carborane-Gd-DTPA, further studies of the synthesis and in vivo evaluation of better binary compounds are continuing.
Endo, Kiyoshi*; Shibata, Yasushi*; Yoshida, Fumiyo*; Nakai, Kei*; Yamamoto, Tetsuya*; Matsumura, Akira*; Ishii, Keizo*; Sakai, Takuro; Sato, Takahiro; Oikawa, Masakazu*; et al.
Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 2 Pages, 2004/10
Micro PIXE, which is installed in a single end accelerator in JAERI, was used for quantitative analysis of boron and gadolinium distribution in a cell level. The micro beam of 1 m diameter is possible to observe the distribution. In the adjustment procedure of the sample, first is a fix of mylar film by using a glass ring and a bite ring of 2cm diameter. Next the 9L cells were scattered on the washed film, and is cultivated on 37C in medium until they form the mono-layer. After the Gd-BOPTA was added, it incubates for the 24-72 hour on 37C. The film is washed in the THAM liquid, and is directly put on liquid nitrogen. A vacuum drying for 24 hours is conducted in order to fix a film on holder. It is important to uniformly fix the cell in distribution analysis in the cell using Micro PIXE. In recent result, it became possible that the distribution of P, S, Gd, etc. was analyzed. But we could not distinguish whether K and Gd exist in the cell or whether it exists around the cell. It was indicated that these elements was leaked by the reason of cell breaking or other on the cytoplasm.