RADIOISOTOPES

The Rational Estimator Method for Gamma-Ray Peak Area Determination

Kazuo TERANISHI, Kan-ichi FUJII, Hiroshi GOTOH

1994 Volume 43 Issue 12 Pages 735-740
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_735

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A determination method of the gamma-ray peak area and its uncertainty is described for a well-resolved single peak. The method needs no fitting the peak region, and the lower and the upper background regions to some analytical function such as the normal distribution function or the second degree polynomial, but instead, it fits a rectangular polygon to the peak region and a flat straight line to each background region, respectively. The peak area and its standard error are given by the rational expressions of counts and a set of some channel numbers in the peak region, and the lower and the upper background regions. An algorithm of these expressions is coded with BASIC laguage for a personal computer. An example of the peak area determination is shown for nine gamma-ray peaks of a ¹⁵²Eu source obtained by a high purity Ge detector.

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Radiation Characteristics of Tritium Plane Sources for Calibration of Surface Contamination Monitoring Instruments

Makoto YOSHIDA, Koji TAKAHASHI, Shigeru SHIMIZU

1994 Volume 43 Issue 12 Pages 741-749
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_741

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Radiation characteristics of tritium plane sources have been studied for calibration of surface contamination monitoring instruments. On estimation of the radiation characteristics, three typical tritium sources of monomolecular layer, polymer and anodized aluminum were selected. Surface emission rates and energy distributions of the β-rays and X-rays emitted from the sources were measured using a windowless proportional counter. As a result, it turned out that the structural difference of sources influenced the calibration of instrument efficiency mentioned in ISO reports. And the suitable type of tritium source for routine calibration works was concluded. In addition, the efficiency of contamination source in the ISO reports was discussed for direct determination of tritium surface activity.

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Improvement of Hygienic Quality of White Ginseng Powders by γ-Irradiation

Han-Ok CHO, Myung-Woo BYUN, Il-Jun KANG, Hong-Sun YOUK, Joong-Ho KWON

1994 Volume 43 Issue 12 Pages 750-759
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_750

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For the purpose of improving hygienic quality of white ginseng powders, the comparative effects of ethylene oxide (EO) fumigation and γ-irradiation (5 -10 kGy) on the sterilization, physicochemical properties and organoleptic quality were investigated. EO fumigation and γ-irradiation (5-10 kGy) completely eliminated the microorganisms contaminating in white ginseng powder. There was no growth of microorganisms after 7 months storage at 30°C and different relative humidities. In the physicochemical properties, ginseng saponins were considerably resistant to γ-irradiation (less than 10 kGy) and commercial EO fumigation, while sulfur-containing amino acids, reducing sugar and acidity were significantly changed by EO fumigation. EO residues were 570 ppm in the samples taken immediately after deaeration and 170 ppm in the stored samples of 8 days at 30°C, respectively. Ethylene chlorohydrin and ethylene glycol residues as the secondary products of EO were 9595 ppm immediately after deaeration and 221 ppm in the stored samples of 3 months at 30°C.

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Patients without Myocardial Accumulation of ¹²³I-metaiodobenzylguanidine Does it always reflect cardiac adrenergic dysfunction?

Michihiro NARITA, Tadashi KURIHARA, Minoru HONDA, Osamu HOHJOH

1994 Volume 43 Issue 12 Pages 760-769
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_760

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Since December 1992 to March 1994, we have performed myocardial imaging with ¹²³I metaiodobenzylguanidine (¹²³I-MIBG) in 110 patients to examine myocardial sympathetic integrity. Among them 11 patients (10%) showed no accumulation of ¹²³I-MIBG in the heart. So we have examined the mechanisms of no myocardial ¹²³I-MIBG accumulation.
¹²³I-MIBG imaging was obtained at 20 min and 3 h after intravenous injection of ¹²³I-MIBG (148 MBq) at rest. In addition to routine tomography, anterior planar imaging of the heart and the whole body imaging were performed. Eleven patients without myocardial ¹²³I-MIBG accumulation consisted of 5 patients with orthostatic hypotension (including 3 patients with diabetic neuropathy), four patients with hypertrophic cardiomyopathy (HCM), one patient with hypertension and one normal subject. In patients with orthostatic hypotension, standing test showed cardiac sympathetic dysfunction. In addition to no myocardial ¹²³I-MIBG accumulation, accumulation of ¹²³I-MIBG in the salivary glands was not found in all of them. These indicated that in patients with orthostatic hypotension, generalized sympathetic dysfunction caused no myocardial ¹²³I-MIBG accumulation. But in other 6 patients there was no evidence which suggested the cardiac sympathetic nerve dysfunction. Age, sex, serum norepinephrine level, myocardial perfusion and the medication were not different between the patients with and without myocardial ¹²³I-MIBG accumulation. So the mechanism of no myocardial ¹²³I-MIBG accumulation was not clear in these patients. But it was noteworthy that in patients with HCM, no myocardial ¹²³I-MIBG accumulation appeared in 17% (4/24), and the frequency of no myocardial ¹²³I-MIBG accumulation in HCM was significantly (p<0.05) higher than in other disease entities when patients with orthostatic hypotension were excluded.

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Application of ²²²Rn to the Analysis of the Exchange between River Water and Groundwater

Hiromasa HAMADA, Takami KOMAE

1994 Volume 43 Issue 12 Pages 770-775
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_770

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As ²²²Rn is an inert gas generated from ²²⁶Ra in soils and rocks, ²²²Rn concentration in groundwater is higher than in river water. It is, therefore, possible to determine a section by measuring ²²²Rn concentration in the stream where groundwater is seeping into the river. Moreover, the simultaneous equations of water balance and ²²²Rn balance make it possible to quantify groundwater seepage and river water infiltration at the same time. However, as the ²²²Rn loss in a stream is estimated directly by measuring the decrease in ²²²Rn concentration in river water, the traditional method of analysis using ²²²Rn is applied only to a river which has a section with no groundwater input.
In this paper, the authors proposed a new method to analyze an exchange between river water and groundwater using ²²²Rn which is applicable to a river in any condition. The ²²²Rn loss in a stream was calculated assuming that a stagnant film existed at the boundary between water and air. Its thickness was estimated as 20μm from field investigations and the previous research. The method using ²²²Rn was applied to the Omoi River Basin, Tochigi, and the groundwater seepage and the river water infiltration were quantified simultaneously. The obtained values were within reasonable ranges and the applicability of the method using ²²²Rn was troved.

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Development of β-Ray Tracking Technique for Studying Hydrogen Behavior of Radiation Damaged Fe-Cr-Ni Alloy

Seigoroh YAMAMOTO, Minoru MORI, Yoichi ISHIDA

1994 Volume 43 Issue 12 Pages 776-780
Published: December 15, 1994
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_776

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Hydrogen behavior in an Fe-Cr-Ni alloy is very important for the investigation of hydrogen embrittlement. This paper shows the hydrogen trapping sites in an Fe-Cr-Ni alloy, which have not been clarified with conventional techniques, using β-ray tracking technique. This technique, application of tritium TEM-ARG (transmission electron microscopic autoradiography) technique, is applied to the visualization of hydrogen trapping sites in a radiation damaged Fe-Cr-Ni alloy.

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Application of Electron Beam Irradiation (4)

Treatment of pollutants by electron beam irradiation

Okihiro TOKUNAGA, Hidehiko ARAI

1994 Volume 43 Issue 12 Pages 781-790
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_781

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Handling Technique of Spore-forming Bacteria in Radiation Sterilization (II)

Determination of numbers and radiation resistance of spores

Tomihiko KOSHIKAWA

1994 Volume 43 Issue 12 Pages 791-797
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_791

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Application of Radioisotopes to Therapies. V. The latest brachyterapy

—¹⁹²Ir high-dose rate technique—

Toshihiko INOUE, Takehiro INOUE, Takayuki NOSE

1994 Volume 43 Issue 12 Pages 798-808
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_798

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[title in Japanese]

[in Japanese]

1994 Volume 43 Issue 12 Pages 809-810
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_809

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[title in Japanese]

[in Japanese]

1994 Volume 43 Issue 12 Pages 811-812
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_811

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[title in Japanese]

[in Japanese]

1994 Volume 43 Issue 12 Pages 813-814
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_813

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[title in Japanese]

[in Japanese]

1994 Volume 43 Issue 12 Pages 815-816
Published: December 15, 1994
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.43.12_815

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