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Biomedical subjects

M Takiue

Publications and source records attributed to M Takiue.

13 recordsLinked to original sources
PubMed2001

Foggy scintillation counting technique.

A new "foggy scintillator" was developed for the measurement of low-energy beta-emitters in air. By the use of an ultrasonic wave generator, a liquid scintillator can be converted into the "foggy scintillator". In order to obtain reasonable detection efficiency, it is necessary to prepare a liquid scintillator with a very high concentration of the first solute (PPO). The foggy scintillation counting technique avoids the trouble of the sample preparation usually necessary for the measurement of radionuclides in air, since the radionuclide in the air can be measured directly.

Journal Article↗
PubMed2000

Monitoring of 3H surface contamination by noncontact radioluminography.

A phosphor screen imaging technique has been developed to detect 3H contamination on floor surfaces. A 3H imaging plate is elevated a maximum of 0.1 cm above the surface being monitored. This technique prevents the imaging plate from being cross-contaminated. Unlike the traditional smear test, this technique can be used to monitor fixed contamination.

Humans↗
PubMed2000

Hybrid radioassay of multiple radionuclide mixtures in waste solutions by using liquid and NaI(Tl) scintillation monitors.

A new analytical technique for radioactive waste solutions has been developed by using a combination of a liquid and a NaI(Tl) scintillation monitor, which enables beta-emitter mixtures to be radioassayed using one calculation process with the method of least squares. This hybrid system can facilitate the analysis of beta-emitter mixtures with very similar liquid scintillation pulse height distributions, such as 3H, 51Cr, and 125I. All that is required for the technique are sets of quench standards of the nuclides to be analyzed and calibration standards for the gamma-emitters. Detection limits for seven nuclides were estimated to be about 0.005 Bq mL(-1), which are sufficiently low compared with the values of authorized safety guidelines.

Chromium Radioisotopes↗
PubMed1999

[Usefulness of visualized highly sensitive new chemical dosimeter: application to blood irradiation].

In the prophylaxis of post-transfusion GVHD, it is recommended to irradiate blood components with an absorbed dose ranging from 15 Gy to 50 Gy. We applied a new chemical dosimeter to measure absorbed dose for blood irradiation. This system is composed of diphenyliodoniumchloride (DICI) as an oxidizer and crystal violet lactone as a pH indicator. Protons are released from DICI after irradiation. The maximum absorption wavelength of this indicator is 610 nm, and absorbance is linearly related with a given dose from 1 to 50 Gy. Coloration is stable for at least 2 weeks when stored in the dark at 4 degrees C. This system may be used as a chemical dosimeter for blood irradiation.

Blood↗
PubMed1989

Paraffin scintillator for radioassay of solid support samples.

A new paraffin scintillator used for solid support sample counting has been proposed, and its composition and various characteristics are described. The solid support sample treated with this scintillator can be easily handled because of rigid sample conditions. This technique provides great advantages such as the elimination of a large volume of scintillator and little radioactive waste material by using an economical polyethylene bag instead of the conventional counting vial.

Chromatography↗
PubMed1981

[Activity determination of filter sample with liquid scintillation measurement (author's transl)].

The technique for solubilization of various filter samples into a liquid scintillator has been established to overwhelm the inherent shortcomings of a disc counting technique. Conventional liquid scintillation measurement methods that employ the quenching correction methods can be adopted to the homogeneously dispersed filter samples, which consequently enable the activity of the filter samples to be determined. This technique involves a resolution of the last problem in a sample preparation technique.

Filtration↗
PubMed1978

[Studies on halogen quenching through the Stern-Volmer plot (author's transl)].

The quenching effect for halogenated benzenes, methanes and ethanes have been investigated. The halogen quenching was accurately measured using the internal conversion electrons emitted from 113Sn-113mIn. From the quenching constants determined by the Stern-Volmer plots with respect to various halogen quenchers, the following results have been obtained. (1) The quenching constants increase with the number of halogen substituents, so as linearly in halogenated benzenes and exponentially in halogenated methanes and ehtanes. Even the isomers of halogenides have different quenching constants. (2) There is a linearity between logarithm of the quenching constant and a polarographic half-wave reduction potential. (3) Electron excitation provides larger quenching constants than UV excitation for halogenated methames. Based on these results, the mechanism of halogen quenching have been discussed in connection with the exciplex formation.

Benzene↗
PubMed1978

[Improvement of Cherenkov counting method (author's transl)].

Cherenkov counting efficiency has been considerably improved by a specified measuring geometry. Radioactive sample and wavelength shifter are separately dispositioned, where a butyl-PBD has been employed as a wavelength shifter in the form of liquid and solid solutions. This technique can get rid of the shortcoming of the method usually used, in which wavelength shifter is directly incorporated to Cherenkov medium.

Radiometry↗