RADIOISOTOPES

Uranium and Thorium Contents and Radioactive Equilibrium of U-series Nuclides in Phosphorites

Minoru TAKADA, Asaya KOBASHI, Jun SATO, Nobufusa SAITO

1987 Volume 36 Issue 5 Pages 213-220
Published: May 15, 1987
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_213

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Nondestructive γ-ray spectrometry and α-ray spectrometry have been applied to determine ²³⁸U, ²³⁴U, ²²⁸Ra, ³¹⁰Pb and ²³²Th in 30 phosphorite samples from various parts of the world. Instrumental neutron activation analysis has also been employed on a supplementary basis for the determination of thorium in the phosphorites. The results indicate that the uranium and thorium contents of sedimentary phosphorites are generally higher than those of guano phosphorites. In most of the phosphorites studied, ²³⁸U can be regarded to be in equilibrium with ²³⁴U, ²²⁶Ra and ²¹⁰Pb. However, several phosphorites clearly exhibit radioactive disequilibrium among these nuclides. It is suggested that geological processes such as migration of uranium and selective removal of radium on the sites of phosphorite deposits, and recent phosphatization may account for the disequilibria.

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Count Rate Characteristics and Count Loss Correction of POSITOLOGICA II: A Whole Body Positron Emission Tomograph

Masahiro ENDO, Norimasa NOHARA, Takeshi A. IINUMA, Hitoshi SHINOTO, Ei ...

1987 Volume 36 Issue 5 Pages 221-226
Published: May 15, 1987
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_221

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This paper describes evaluation and correction of count rate characteristics of POSITOLOGICA II, a multi-slice whole body positron emission tomography system. The present study was performed using three phantoms; (1) a 5 cm inner diameter, water-filled lucite cylinder, (2) a 20 cm inner diameter, water-filled lucite cylinder and (3) a chest phantom. After injection of high activity (about 1.85 GBq (50 mCi) ) of ¹³N ammonia into each phantom, rates of true coincidence, random coincidence and single photon detections were measured during decay of the isotope through more than two orders of magnitude of activity. At very high levels of activity, count rate characteristics of the system were saturated and limited to 660 kcps of total coincidence rate, which was the sum of rates in on-time and off-time windows, by the FIFO (first-in first-out) output frequency. Below those levels of activity the relationship between count loss and true coincidence rate was not unique but depended on the phantom configurations, suggesting that count loss correction using the above relationship was inadequate for quantitative study. However, the relationship between count loss and single rate was almost independent of the phantom configurations. Thus in conclusion count loss could be corrected using single rate for POSITOLOGICA II. A practical method of count loss correction was also proposed.

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A Study on Intestinal ⁴⁷Ca Absorption Test by Employing Scintillation Camera

Kazutami TORIZUMI, Ryusaku YAMADA, Kiichiro OTA, Shoichi EBISUNO

1987 Volume 36 Issue 5 Pages 227-231
Published: May 15, 1987
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_227

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In order to evaluate the clinical application of the calcium absorption test from the intestine, the intestinal ⁴⁷Ca absorption test by using a scintillation camera was carried out in our laboratory.
The results in the intestinal ⁴⁷Ca absorption test using a scintillation camera showed a good correlation to the results which were estimated by using an arm counter previously reported by us.
The rate of intestinal ⁴⁷Ca absorption in 8 healthy volunteers (5 male, 3 female, average age: 37.6±9.5 years) was 52.0±3.8%, 74.3% in a patient with primary hyperparathyroidism 30.4% and 32.7% in two patients with idiopathic hypoparathyroidism respectively.
This method is more easily handled and can be performed for only 4 days in institutes that are set up with scintillation camera without any special preparations, and it is recommended to be of clinical usefulness for the diagnosis of calcium metabolic disorders.

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Determinations of Silicon and Phosphorus in Pepperbush Standard Reference Material by Neutron Activation and X-Ray Fluorescence Methods

Yoshihiko MIZUMOTO, Hirofumi NISHIO, Takeshi HAYASHI, Toshio KUSAKABE, ...

1987 Volume 36 Issue 5 Pages 232-234
Published: May 15, 1987
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_232

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Silicon and phosphorus contents in Pepperbush standard reference material were determined by neutron activation and X-ray fluorescence methods. In neutron activation analysis, β-ray spectra of ³²P produced by ³¹P (n, γ) ³²P reaction on Pepperbush and standard samples were measured by a low background β-ray spectrometer. In X-ray fluorescence analysis, the standard samples were prepared by mixing the Pepperbush powder with silicon dioxide and diammonium hydrogenphosphate. Characteristic X-rays from the samples were analyzed by a wavelength dispersive X-ray fluorescence spectrometer. From the β and X-ray intensities, silicon and phosphorus contents in Pepperbush were determined to be 1840±80 and 1200±50μg g^-1, respectively.

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Evaluation and Comparison of High-sensitivity Immunoradiometric Assay Kits for Thyroid Stimulating Hormone

Ikuko TSUKAMOTO, Sadatoshi YASUDA, Ichiro HINO, Yoshiro KAWASE, Hiroyu ...

1987 Volume 36 Issue 5 Pages 235-238
Published: May 15, 1987
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_235

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Fundamental and clinical characteristics of 3 kinds of high-sensitivity immunoradiometrie assay (IRMA) kits for thyroid stimulating hormone (TSH) . i.e., RIA BEADS II (kit A), TSH kit Daiichi II (kit B) and Ab tube TSH ‘Eiken’ (kit C) and one conventional radioimmunoassay (RIA) kit, i.e., TSH kit Daiichi (kit D), were studied. In the recovery test and the reproducibility test, there was no significant difference between the 4 kits. The sensitivities of kits A, B and C were much higher than that of kit D, and those IRMA kits were sensitive enough to distinguish hyperthyroidism from normal samples. For low concentrations of TSH (<5μU/ml), the data from kits D, B, C and A tended to show higher values in that order. The correlation between the data measured by kits B and D, and the tendency of kit A toward lower values agreed well with other reports.

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Recent Discussions and Summary on the Quality Factor of Fast Neutrons

Hiromichi MATSUDAIRA

1987 Volume 36 Issue 5 Pages 239-246
Published: May 15, 1987
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_239

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Handling Manual for Brachytherapy Sources. III. Practice of Radiation Protection for Therapeutic Uses of Small Sealed Radioactive Sources

(2) Protection of Medical Staffs

Takashi MARUYAMA, Kanae NISHIZAWA

1987 Volume 36 Issue 5 Pages 247-252
Published: May 15, 1987
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_247

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[title in Japanese]

1987 Volume 36 Issue 5 Pages A33P-A54M
Published: May 15, 1987
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.36.5_A33P

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