RADIOISOTOPES

Automatic Stop Type SPE Tritium Enrichment Apparatus

Masaaki SAITO, Sigeru TAKATA

1996Volume 45Issue 8 Pages 483-490
Published: August 15, 1996
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.483

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A water sensor was attached to the tritium enrichment apparatus which we had developed with solid polymer electrolyte. When water is decomposed to a constant volume, the sensor cut the electric source off automatically. The function enabled to get enriched water at the same volume for every electrolysis run. Associated to the function, a tritium measurement without enriched water volume data was proposed. The tritium concentration T_i was expressed as follows. T_i=T_f/ {10^{[A⋅log (V_i) +B]}}, T_f : enriched tritium concentration, V_i : sample water volume, A and B : constants. By this, we solved the problem about the enriched water volume that had been held in porous electrodes. The reliability of the apparatus was improved in addition to advantages ; the reduction of electrolysis time, easy and safe procedure.

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Elimination of Background and Kidney Depth Correction during Renal Uptake Rate Measurement with ^99mTc-Dimercaptosuccinic Acid Using a Kinetic Modeling Approach

Kenya MURASE, Shuji TANADA, Ken HAMAMOTO

1996Volume 45Issue 8 Pages 491-499
Published: August 15, 1996
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.491

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Renal uptake rate measurement with ^99mTc-dimercaptosuccinic acid (DMSA) requires accurate background and kidney depth correction as well as several hours for the examination. We developed a new method which required no correction and only 20 min for examination using the kinetic modeling approach. Our model consists of three compartments with the rate constants for the transport of DMSA from blood to renal tissue (k₁), from tissue to blood (k₂), and DMSA uptake in the tissue (k₃) . In addition, we introduced a parameter indicating the blood pool fraction, rather than correcting for background. The parameters were calculated by fitting the model equation to the time-activity curve obtained by injection of 148 MBq of DMSA and sequential imaging for 20 min. The net uptake rate of DMSA by tubular cells (K) was also calculated from K=k₁×k₃/ (k₂+k₃) . The K values obtained without background and kidney depth correction were well correlated with the renal uptake rates measured two hours after DMSA administration (r=0.918, n=120), and with those obtained using background correction (r=0.989) or correction for attenuation due to kidney depth (r=0.982) . Our results indicate that this is a promising method of quantifying renal cortical function, as it requires no correction and only 20 min for image acquisition.

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Analytical Estimation of γ-Ray Shielding Generated by Neutron Capture

Yoshiaki NISHIHARA

1996Volume 45Issue 8 Pages 500-506
Published: August 15, 1996
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.500

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Radiation shielding is very important not only in nuclear reactor sites but also in facilities for accelerator and radioisotope applications. In order to estimate the shielding thickness, Sn transport method and Monte-Carlo calculation have been widely used and are considered to give us useful and precise results. Although those calculation methods are not always necessary for all the shielding problems, we sometimes have to estimate the neutron distributions in shielding materials including capture gamma-rays generated by neutron capture.
An analytical formula derived here seems to be a fair tool for shielding calculation of capture gamma-rays. This paper shows the derivation of the formula, and the results and discussions of the calculation by comparing them with Sn transport calculation and measured data.

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Airborne Exhalation of Radioactivity from Animals Injected with Radioactive Substances

Toshiyuki NISHIMAKI, Senichi FURUDATE

1996Volume 45Issue 8 Pages 507-510
Published: August 15, 1996
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.507

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Few reports were published on exhalation of a radioactive substance into the air from animals injected with it. For safe handling of iodine-125 in research using animals, we examined daily changes of airborne release of radioactivity from housing cages, containing mice treated with Na ¹²⁵I or ¹²⁵I labelled anti-mouse monoclonal IgG₁κ. Airborne radioactivity was collected during 100 min with a flow rate of 10l/min with charcoal filters and measured every 24 h during the period of 4 days. Radioactivity in the removed organs was also measured after 96 h of the time when the mice were sacrificed. Different patterns were observed in airborne radioactivity for different chemical forms of injected radioisotope, i.e. Na¹²⁵I or ¹²⁵I labelled anti-mouse monoclonal IgG₁κ. For Na ¹²⁵I injection, the radioactive concentration in air was highest at 24 h after injection. The concentration decreased gradually from 24 to 96 h, to one seventh at 96 h. Contrary, in the ¹²⁵I labelled anti-mouse monoclonal IgG₁κ injection, the radioactivity was low at 24 h and became highest at 96 h. The radioactivity only in the thyroid gland was higher in the Na ¹²⁵I than in ¹²⁵I labelled anti-mouse monoclonal IgG₁ κ injection. The radioactivity in the submaxillary gland, liver, kidney, stomach and lung was higher in the ¹²⁵I labelled anti-mouse monoclonal IgG₁κ than in Na ¹²⁵I injection. These results indicate that the different chemical forms of ¹²⁵I compounds show different patterns not only in the distribution in the organs but also in the exhalation.

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Production of ^95mTc Tracer for ⁹⁹Tc Analysis by ICP-MS

Noriyuki MOMOSHIMA, Seiichi SHIBATA

1996Volume 45Issue 8 Pages 511-514
Published: August 15, 1996
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.511

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Analysis of ⁹⁹Tc in the environment have been interested because of a long term radioecological effect of ⁹⁹Tc due to its long half-life. One of the problems on ⁹⁹Tc analysis is a tracer since there is no stable isotope in Tc. Development of ⁹⁹Tc determination by ICP-MS enables us to use ^95mTc as a yield monitor. The radiochemical yield is evaluated by gamma spectrometry of ^95mTc and ⁹⁹Tc is determined by mass spectrometry without any in-terference by ^95mTc tracer added to the sample. We produced ^95mTc without ⁹⁹Tc by an irradiation of metal Nb with 40MeV alpha particles using cyclotron. The 0.1 mm thickness Nb foil stacked 4 pieces was irradiated for 21 h at beam current of 1.5μC, dissolved in a mixture of HNO₃ and HF, and ^95mTc was isolated and purified chemically. No contamination of ⁹⁹Tc was confirmed on ^95mTc fraction.

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Development of Free Electron Lasers and Their Applications

Takio TOMIMASU

1996Volume 45Issue 8 Pages 515-526
Published: August 15, 1996
Released on J-STAGE: December 13, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.515

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[title in Japanese]

[in Japanese]

1996Volume 45Issue 8 Pages 527-530
Published: August 15, 1996
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.527

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[title in Japanese]

[in Japanese]

1996Volume 45Issue 8 Pages 531-532
Published: August 15, 1996
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.531

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[title in Japanese]

[in Japanese]

1996Volume 45Issue 8 Pages 533-534
Published: August 15, 1996
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.533

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese]

1996Volume 45Issue 8 Pages 535-536
Published: August 15, 1996
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.45.535

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