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Volume 52, Issue 3
Displaying 1-6 of 6 articles from this issue
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Yoshiyuki SHIRAKAWA2003 Volume 52 Issue 3 Pages 111-117
Published: March 15, 2003
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThree prototypes of directional detectors, which positively increase directional sensitivity for incident gamma rays, have been developed to measure directions of incident gamma rays. In the detector, a cylindrical NaI (Tl), the same sized BGO scintillator and a photomultiplier tube are combined optically in this order. Sizes of scintillators are 5.0 cm in diameter and 2.5 cm in length (A type), 5.0 cm in diameter and 5.0 cm in length (B type), 2.5 cm in diameter and 5.0 cm in length (C type) .Since gamma ray pass length of crossing each scintillator is changed related to the incident direction θ, the probabilities of photoelectric absorptions in both scintillators are also changed. As a result, photoelectric absorption peak counts in a spectrum also have a relation to θ. This relation is expressed by the ratio R of BGO counts / NaI (Tl) counts with respect to θ. Using this function, the sensitivity of each detector to θ is estimated.
Experiments were carried out for purposes of 1) Confirmation of the measurement principle and 2) Estimation of the sensitivity. A 137Cs source of 3.7 MBq was put 100 cm in front of the detector. Incident gamma rays were counted for 300 s, and the ratio R was calculated observing from the spectrum. The source was moved in each 10-degree interval toward the side of the detector to 90 degrees. The experimental results showed that the ratio R continuously increased from 1.605 to 2.855 for the A type detector, from 0.548 to 2.602 for the B type detector and from 0.792 to 5.187 for C type detector, when the direction θ changed from 0 to 90 degrees. This means that the incident direction θ can be determined when the ratio R is given. It was also found that the C type detector with a slender shape indicated high sensitivity to direction change.View full abstractDownload PDF (1954K) -
Hiroko TANABE, Michiko GOTO2003 Volume 52 Issue 3 Pages 118-127
Published: March 15, 2003
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThe amount of hydrocarbons (HC) and 2-alkylcyclobutanones (RCB), which are both radiolytic compounds of lipid from irradiated rainbow trout, were measured by continuous analysis method. The results are discussed in relation to the possibility of detecting irradiated rainbow trout.
Various hydrocarbons were formed in irradiated rainbow trout and saturated hydrocarbons were detected in unirradiated sample. Therefore, the amount of hydrocarbons is not suitable for the marker of irradiation. In addition, it is found that ratio of radiation-induced Cn-1: 0 and Cn-2: 1 does not result in correct identification of irradiated rainbow trout.
1, 7-Hexadecadiene was detected only in irradiated sample, and amount formed was in direct proportion to doses between 1-11 kGy. 2-Dodecylcyclobutanone and 2-tetradecylcyclobutanone were formed at half the amount of Cn-2: 1 which were formed from the same fatty acids, and the amount of them were in direct proportion to doses. These results indicate that it is possible to identify irradiated rainbow trout by measuring the amount of Cn-2: 1 and RCB using continuous analysis method. In addition, by measuring ESR of high-density bone after additive re-irradiation, dose irradiated was able to be estimated.View full abstractDownload PDF (1064K) -
Hajime MONZEN, Yeunhwa GU, Takeo HASEGAWA, Rumio YUKI2003 Volume 52 Issue 3 Pages 128-135
Published: March 15, 2003
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSAlthough some studies have suggested that certain substances, such as vitamins and glucan, found in natural food products may have protective effect against radiation injuries, no substance is used practically as radioprotectors. Safe radioprotectors without side effects are, however, yet to see. Enterococcus faecalis (Ef) in intestines is known to enhance immunity of the host as a biological response modifier. In this report, we have examined the radiation protection effect of Ef using C3H mice and assessed the effect of Ef on the natural killer cells activity of the splenic cells in the mice. Less body weight losses after irradiation were observed among Ef injection groups, in comparison with control groups. Our data showed a strong tendency to prolong the surviving fraction among the groups with the Ef injection. Hence, the Ef treatment appeared to have protected mucosal damage caused by the X-ray irradiation. The NK cells activities were markedly enhanced after the Ef injection as well. With the evidence mentioned above, we conclude that the Ef may have positive effect on patients who undergo a radiotherapy.View full abstractDownload PDF (4429K) -
Hideharu MATSUDA2003 Volume 52 Issue 3 Pages 136-143
Published: March 15, 2003
Released on J-STAGE: July 21, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...2003 Volume 52 Issue 3 Pages 144
Published: March 15, 2003
Released on J-STAGE: July 21, 2010
JOURNAL FREE ACCESSDownload PDF (116K) -
Toshio NAKAMURA2003 Volume 52 Issue 3 Pages 145-171
Published: March 15, 2003
Released on J-STAGE: July 21, 2010
JOURNAL FREE ACCESSDownload PDF (3123K)
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