RADIOISOTOPES

LSO and GSO: Performance Evaluation for PET

Seiichi YAMAMOTO

1997Volume 46Issue 5 Pages 265-271
Published: May 15, 1997
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.265

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We have measured pulse shape and pulse height of the promising scintillators, LSO and GSO, and compared with those of BGO. The decay time of the LSO was approximately 40 ns, 1/8 of the BGO, and the light output was approximately 3.8 times of the BGO. The decay time of the GSO was approximately 50 ns, 1/6 of the BGO, and the light output was approximately 1.7 times of the BGO. As the decay time of GSO can be controlled by the concentration of Ce doped in GSO, it was possible to separate two GSOs by using the pulse shape analysis. The possibility of performance improvement of PET by using BGO or GSO was also discussed.

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A Study on the Prefectural Distribution of Radioactive Cesium Concentrations in Dried Lentinula edodes (Shiitake) Produced in Japan

Masami SHIMIZU, Ikuro ANZAI, Masahiro FUKUSHI, Yoshiyuki NYUUI

1997Volume 46Issue 5 Pages 272-280
Published: May 15, 1997
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.272

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After the Chernobyl nuclear power plant accident, relatively high radioactive cesium levels were detected in various mushrooms produced in many countries. Mushrooms have a high transfer factor, showing a relatively high uptake of cesium from wood and soil from which they grow.
In the present investigation, we analysed radioactive cesium concentrations contained in the dried Lentinula edodes (Shiitake) produced in various prefectures all over Japan, and examined the effectiveness of this mushroom as an indicator of radioactive contamination of environment due to nuclear explosion tests and Chernobyl power plant accident.
We collected dried Lentinula edodes (Shiitake) grown on the wood from 32 prefectures from north to south, and measured ¹³⁷Cs and ¹³⁴Cs concentrations with high purity Ge-detectors. Levels of ¹³⁷Cs concentration were found to vary from 3.4 to 33.6 Bq/kg, while those of ¹³⁴Cs were less than detectable.
¹³⁷Cs concentrations in Lentinula edodes (Shiitake) samples showed a statistically significant positive correlation with those in rain and dry fallout at 1% significance level. They also proved to have been inversely correlated with atmospheric temperature at 10% significance level, but it could not be determined whether it was only an apparent correlation or not because no information of ¹³⁷Cs concentrations in wood was available. Multiple correlation coefficient of ¹³⁷Cs concentrations with atmospheric temperatures and fallout levels was 0.54 which was statistically significant at 2.5% level. A variance analysis based on the ¹³⁷Cs concentrations in Lentinula edodes (Shiitake) classified into 7 groups (Hokkaido-Tohoku, Kanto, Chubu, Kinki, Chugoku, Shikoku and Kyushu) showed that the variance between the groups was significantly greater than that within each group, which suggested, together with the above-mentioned information regarding the correlation of ¹³⁷Cs concentration in Lentinula edodes (Shiitake) with average temperatures and fallout levels, that the ¹³⁷Cs levels in Lentinula edodes (Shiitake) are possibly related with these two factors.

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Scattering of Gaseous ¹²⁵I from a Bottle Contanining Na¹²⁵I Solution for Iodination in a Calm Condition

Katsumi AOKI, Yuko FURUSE, Toshiyuki NISHIMAKI, Akiko SHINOZUKA

1997Volume 46Issue 5 Pages 281-283
Published: May 15, 1997
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.281

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Scattering of gaseous ¹²⁵I from a bottle containing Na¹²⁵I solution for iodination has been measured by distributing active charcoal granule at various heights on the inner surface of a plastic cylinder surrounding the bottle and counting the activities of granule samples. The result shows that about 70% of total scattered ¹²⁵I exist below the level of mouth of the bottle. By drawing the air from the bottle of the cylinder through a tube filled with active charcoal, about 90% of scattered ¹²⁵I collected.

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Circumferential Profile Analysis of ²⁰¹Tl Myocardial SPECT

—A Comparative Study between Various Profile Curves—

Mitsuharu SHIMIZU, Hidekiyo YANAGI, Tomio NAKAGAWA, Shuhei SATOH, Haru ...

1997Volume 46Issue 5 Pages 284-290
Published: May 15, 1997
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.284

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Circumferential profile analysis is one of quantitative analyses in ²⁰¹Tl myocardial scintigraphy. We compared the detectability of coronary artery stenosis between 4 various methods of circumferential profiles (peak point method, all points method, 3 points around the peak method and average method) based on short-axial images of ²⁰¹Tl myocardial single photon emission computed tomography. Diagnostic criteria for coronary artery stenosis was that the circumferential profile curve of a patient was below the normal limit (mean—2SD) obtained from 23 normal volunteers in more than serial 3 profiles. After examining 16 patients with coronary artery stenosis demonstrated by coronary arteriography, it was concluded that both peak point method and 3 points around the peak method surpassed other methods in the detectability of clinically significant coronary artery stenosis.

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Measurement of Environmental γ-Ray Dose in Hokkaido Using a Portable γ-Spectrum Survey Meter

Takahiro WAJIMA, Yoichiro HOSOKAWA, Mitsuo TAKEKOSHI, Satoshi FUJITA, ...

1997Volume 46Issue 5 Pages 291-297
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.291

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Industrial Use of Radioisotopes and Radiation

I. Introduction—Present Status and Its Activation and Standardization

Toshiso KOSAKO

1997Volume 46Issue 5 Pages 298-303
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.298

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Neutron Beam Analyses and Its Application VIII. Neutron Inelastic Scattering

1. Molecular Vibration and Lattice Vibration

Akira INABA

1997Volume 46Issue 5 Pages 304-310
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.304

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2. Spin Fluctuation Studied by Neutron Inelastic Scattering

Kazuyoshi YAMADA

1997Volume 46Issue 5 Pages 311-316
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.311

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3. Slow Dynamics of Macromolecules

Toshiji KANAYA

1997Volume 46Issue 5 Pages 317-321
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.317

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[title in Japanese]

[in Japanese]

1997Volume 46Issue 5 Pages 323-324
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.323

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[title in Japanese]

[in Japanese], [in Japanese]

1997Volume 46Issue 5 Pages 325-326
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.325

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[title in Japanese]

[in Japanese], [in Japanese]

1997Volume 46Issue 5 Pages 327-329
Published: May 15, 1997
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.46.327

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