No abstract available

[en] Fukushima Prefecture is expected to have three nuclear power stations along the Pacific coast. One of them has already been in operation, the other two are now under construction or planning. The original plan includes 14 reactors (ca. 13,000 MWh) in all. Thus, in 1974, Environmental Radioactivity Research Institute of Fukushima Prefecture was established in Okuma town by the local government. The activities of this facility are as follows: (1) Monitoring of environmental radioactivities around the nuclear power stations. (2) Measurement of radioactive fallout. (This work is entrusted by the Science and Tochnology Agency.) (3) Information of the nuclear energy. (author)

[en] Computed tomography equipment provides cross sectional images of human bodies. From these two-dimensional images, doctors can extract useful information for diagnosis. Possibilities of contour extraction and three-dimensional construction of objective regions of affected parts (dilated ventricles) have been investigated on the basis of brain CT images. The perspectives of extracted three-dimensional objects are dynamically displayed on a three-dimensional graphic display system and following conclusions have been obtained. (1) Three-dimensional images provide helpful information for recognizing the shapes of objective regions of affected parts of a brain. (2) The volume and cross sectional area of the object of interest are available from this system. Especially the volumetric ratio of dilated ventricles to cranium has the possibility of becoming a better measure than the conventional one. (author)

[en] The stereo-display system by making three-dimensional construction from a two-dimensional computed tomographic image was developed. It was aimed to develop such system that enables to make three methods of contour extraction; namely extraction by doctors, automated computerized contour extraction, and extraction employing both methods in combination. In order to carry out the completely automated computerized contour extraction, however, further consideration is required to make its algorithm. This three-dimensional stereo-display system is expected to be useful for the investigation of operation methods and the observation of therapeutic progress. Its display of dose ditribution is supposed to contribute to radiotherapy in the future. (Kobatake, H.)

[en] 2-Octyl-4H-1,3,2-benzodioxaphosphorin 2-oxide (octyl-BDPO) was labelled with tritium in the 7,8-octyl and 6-BDPO positions at specific activities of 38 and 16 Ci/mmol, respectively, by catalytic reductions of the corresponding olefin and bromo precursors with tritium gas. This potent mechanism-based inhibitor for neuropathy target esterase (NTE) (I₅₀ 0.25 nM) and delayed neurotoxicant (Active in hens at 3 mg/kg) was designed to determine phosphorylated NTE which retains the octyl label and differentiate aging with or without intramolecular group transfer (''alkylation'') reactions at the NTE active site from the fate of the aryl label. (author)

[en] We examined the relationship between CT visual score and pulmonary function studies in patients with pulmonary emphysema. Lung volume was measured using helium dilution method and body plethysmographic method. Although airflow obstruction and overinflation measured by helium dilution method did not correlate with CT visual score, CO diffusing capacity per alveolar volume (DL_CO/V_A) showed significant negative correlation with CT visual score (r=-0.49, p<0.01). FRC measured by body plethysmographic method was significantly correlated with CT visual score (r=0.49, p<0.01). Trapped gas volume was obtained from the FRC, which was measured by helium dilution method, subtracted by that measured by body plethysmographic method, and it was correlated with CT visual score (r=O.41, p<0.05). These results suggest that CT visual score and DL_CO/V_A reflect pathologic change in pulmonary emphysema. Further, both helium dilution method and body plethysmographic method are required to evaluate lung volume of pulmonary emphysema because of its ventilatory unevenness. (author)

[en] We studied the usefulness of multi-detector-row CT (MDCT) as a preoperative diagnostic tool for detecting combined coronary artery disease in aortic aneurysm. Fifty patients of aortic aneurysm were successfully evaluated by MDCT coronary angiography. Cardiac catheterization was required for further evaluation in 19 patients. We could avoid cardiac catheterization in 62% of patients of aortic aneurysm. We conclude that MDCT is useful to avoid cardiac catheterization in preoperative evaluation for coronary artery disease in aortic surgery. (author)

[en] Laser propulsion has very unique advantage of producing exhausting gas (ions) of very high velocity. Specific impulse from laser plasma could easily exceed 10,000 seconds that reduce the current propellant consumption rate on space born thrusters significantly. For efficient propellant usage, it is desirable that the exhaust plasma has rather narrow velocity distribution of fast ions. In order to accomplish the requirements, thermal conduction and neutral particle losses at and vicinity of the laser heated region have to be eliminated. A concept of spot size limited propellant shape has been proposed and tested in terms of the effects of the loss reduction. Ion and neutral particle measurements from laser plasmas produced on the above mentioned carbon targets are used to characterize the performance of the propellant

[en] Translucent scintillator ceramics of Gd₂O₂S:Pr, Ce, F were fabricated using a hot isostatic pressing (HIP) technique. The optical transmission is about 60 % of the incident light and the X-ray stopping power is also quite high. Owing to the enhancement of these properties by the HIP densification process, the highest light output from a 1 mm thick specimen combined with a silicon photodiode, when excited by 120 kV X-rays, has reached 1.8 times that of CdWO₄ single crystals. The present ceramics are very promising candidates for scintillator materials in X-ray computed tomography (CT) detector applications. (author)

[en] From October 1989 to December 1993, 103 breasts in patients were treated with radiotherapy after breast-conserving surgery at Aichi Cancer Center Hospital. There were 93 stage I and 10 stage II tumors by the classification of the Japanese Breast Cancer Society. As surgical treatment, quadrantectomy, segmentectomy, or lumpectomy with axillary dissection (level II) was performed. Radiotherapy was delivered with two opposing tangential fields of 46-50 Gy using 6-MV photons. For patients with a positive margin, boost electron irradiation to 10 Gy was employed. In median follow-up of 27 months (range 10-60 months), two patients developed recurrence in the treated breast and four patients had distant metastases (1 brain, 2 lung, and 1 bone). As for complications, symptomatic radiation pneumonitis occurred in one case. (author)