Other

University of California

Alain L Fymat

James C Fletcher

Wai-Nang P Lee

Moses A Greenfield

This invention comprises a method and apparatus for measuring both the absolute levels and variations of radioactivity emitted following administration of suitable radioisotopes during a test period by selected organs. Miniaturized radiation detectors for measuring two different types of radiation, such as gamma rays and photons, for example, are modified by the addition of mutual overlap coincidence units, scalers, single channel analyzers and time-gates. The individual detector units are appropriately arranged to form a probe or collar in either a strip or a checkerboard configuration, extending around the neck to study the thyroid gland or other gland organ to be analyzed. The associated electronic architecture is appropriately designed in either simplex or multiplex circuit patterns. Measurements are performed according to an established, preprogrammed time schedule that is reflective of the functional processes of the organ undergoing testing, and which separately determine the background radiation and that emanating from the organ or gland being examined. The data is recorded and processed by a dedicated microcomputer means. With a properly chosen radiopharmaceutical, the measurements provide specific data useful for clinical evaluation of the physiological functions and morphological features of the organ.

Coincidence counting emission tomographic probe: method and apparatus

A particle size spectrometer having a fixed field of view within the forward light scattering cone at an angle .theta..sub.s between approximately 100 and 200 minutes of arc (preferably at 150 minutes), a spectral range extending approximately from 0.2 to 4.0 inverse micrometers (.mu.m.sup.-1), and a spectral resolution between about 0.1 and 0.2 .mu.m.sup.-1 (preferably toward the lower end of this range of spectral resolution), is employed to determine the distribution of particle sizes, independently of the chemical composition of the particles, from measurements of incident light, I.sub.o, at each frequency, .sigma. (=1/.lambda.), and scattered light, I(.sigma.), according to the equation: ##EQU1## where l=2.pi.sin.theta., .theta. being the fixed viewing angle .theta..sub.s at which scattered light is measured, r is particle size, .sigma. is the reciprocal of wavelength, J.sub.1 is a Bessel function of first kind and order unity, Y.sub.1 is a Bessel function of second kind and order unity. The quantity, I.sub..sigma., is the ratio of scattered light to incident light at each frequency interval. The apparatus is a passive remote sensor that can be used in laboratories, field stations, flying aircrafts and airships, and on board an orbiting satellite.

Frequency-scanning particle size spectrometer

A high-resolution Fourier interferometer-spectrophotopolarimeter is provided using (i) a single linear polarizer-analyzer the transmission axis azimuth of which is positioned successively in the three orientations of 0.degree., 45.degree., and 90.degree., in front of a detector; (ii) four flat mirrors, three of which are switchable to either of two positions to direct an incoming beam from an interferometer to the polarizer-analyzer (1) around a sample cell (2) transmitted through a medium in a cell and (3) reflected by medium in the cell; and (iii) four fixed focussing lenses, all located in a sample chamber attached at the exit side of the interferometer. This arrangement can provide the distribution of energy and complete polarization state across the spectrum of (a) the reference light entering from the interferometer; (b) the same light after a fixed-angle reflection from the sample cell containing a medium to be analyzed; and (c) the same light after direct transmission through the same sample cell, with the spectral resolution provided by the interferometer.

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Pasadena, CA, United States of America

Alain L Fymat