The growing particles-gas reaction is very important in the molecular laser isotope separation of uranium-235 (235U) at RIKEN, because an isotope exchange reaction between growing 235U enriched UF5 particles and natural UF6 is thought to be one of the most serious problems which causes the separation factor to deterionate. We present here a new simple calculation method to estimate the influence of this reaction system. Using an exchange reaction probability of 1.1 ×10-9 reported by G. Y. Grigore'v et al, , we found that the influence of the isotope exchange reaction between growing 235U enriched UF5 particles and natural UF6 gas was negligible to the separation factor.
The sensitivities of two types of β-ray ionization chambers to measure the dose-equivalent were evaluated by a tissue equivalent extrapolation ionization chamber. Seven kinds of β-ray sources; 90Sr-90Y, 210Pb-210Bi, 204Tl, 137Cs, 60Co, 147Pm, and 14C with intensities of several MBq were utilized for the evaluation. The measured values were corrected to maximum dose-equivalents at the position of the extrapolation chamber by the multiplying correction factors of the spatial dose distribution to remove the characteristics of the extrapolation ionization chamber. The variation of the sensitivities of one type ionization chamber at the distance between 50 mm and 200 mm from the β source was within ±50% for seven kinds of sources and that of another type ionization chamber was within ±50% for six sources except14C. The variation was also compared with the inverse square characteristic of the absorption dose.
We aimed to detect 3'-hydroxy terminus of DNA single-strand break (ssb) induced with different radiations using a specific enzyme reaction. Dry nuclear sample isolated from barley seeds and placed on the slides were exposed with a monochromic SR of 115, 160, 190, 210 and 260 nm-wavelength, gamma-ray, proton- or deuteron-beam, then DNA synthesis reaction was carried out on the sample using a mixture of 3H-TTP and DNA polymerase I of Escherichia coli et al. Then, microfluorography was carried out. Under the microscope, percentages of 3H-labeled nucleus and numbers of silver grains on a nucleus were observed. Consequently, it was proved that an 160 nm-SR was able to produce ssb on the nuclear DNA even with less than 0.5 V⋅min, while the other 190, 210 and 260 nm-SR yielded no ssb with lower intensity than 3 V⋅min. And, either proton- or deuteron-beam was strikingly effective than gamma-ray. From these data, we suggested that the DNA synthesis reaction is available to detect radiation-induced ssb.
We report the result of immunoscintigraphy by using IMACIS-1, which consists of 131I-labelled F (ab') 2fragments of monoclonal antibodies to anti-carcinoembryonic antigen (CEA) and anti-CA19-9. All of seven patients entered in this study were suffering from malignant diseases with elevated serum levels of CEA or CA19-9. Positive findings were obtained in two patients: One case was suffering from cholangiocarcinoma and the other from metastatic liver tumor due to colon cancer. In both cases, the diameter of the tumor was more than 3cm. Interestingly, in the latter case, the accumulation of IMACIS-1 was not seen in the coexistent hypopharyngeal cancer. Accordingly, despite the limited number of patients, IMACIS-1 was thought to he worth trying in detecting CEA-or CA19-9-producing malignancies or making differential diagnosis of them from the coexistent independent tumors.
99mTc-Galactosyl human serum albumin (99mTc-GSA) is a new liver imaging radiopharmaceutical which specifically binds to the asialoglycoprotein-receptor on the liver cell membrane. We investigated the usefulness of99mTc-GSA for evaluation of the liver function in patients with chronic liver damage. We calculated LHL15 for the index of hepatic uptake and HH15 for the index of clearance. In patients with liver cirrhosis, LHL15 value was higher and HH15 value was lower than those of other groups. Both decrease in LHL15 value and increase in HH15 value were correlated with the severity of the liver damage. Significant correlation was also observed between the prolongation of ICG clearance and both decrease in LHL15 value and increase in HH15 value. In conclusion, these findings indicate that 99mTc-GSA can be a useful agent for evaluation of the liver function in patients with chronic liver damage.