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Biomedical subjects

H Toyama

Publications and source records attributed to H Toyama.

At least 163 records · Page 9Linked to original sources
PubMed1986

[Estimation of 99mTc-dimercaptosuccinic acid renal uptake using single photon emission computed tomography].

Renal function was assessed by measurement of 99mTc-dimercaptosuccinic acid (DMSA) uptake by the kidney based on the transsectional tomographic image obtained by single photon emission computed tomography (SPECT). The renal uptake was expressed as percentage of the total radioactivity detected in the kidney, the volume of which was measured by convolution method, against the amount dosed. Absorption was corrected by GE-STAR method using cut off level of 42%. In order to determine normal range, measurement was made for 40 kidneys of each of 10 male and female volunteers confirmed of having normal kidneys both morphologically and functionally. The average volume of the kidney was 220.4 ml for the right and 239.3 ml for the left for males, and 205.9 ml and 236.5 ml, respectively for females. The renal uptake of radioactivity (at 2 h after injection), was 26.8% for the right and 27.6% for the left for males, with corresponding figures for females being 26.4% and 27.9%, respectively. Distribution range of renal volume and renal uptake was obtained by bivariate analysis with 90% and 95% probability. From these results, our method of renal function determination based on renal uptake of 99mTc-DMSA obtained from renal transactional tomogram by SPECT is considered to be accurate and potentially useful for clinical purpose.

Adult↗
PubMed1986

Automated body contour detection in SPECT: effects on quantitative studies.

To perform accurate in vivo quantitation by single photon emission computed tomography, we have developed a new method for detecting body contours for the correction of tissue attenuation. Our method can rapidly derive the best fit contours throughout the body by using the measured axial length of the patient body and Fourier filtering the detected contours which are defined by a unique bit-plane algorithm. We have also evaluated the effects of the body contours on the reconstructed images by using various attenuation correction techniques including a precorrection method (Sorenson, 1974), a postcorrection method (Chang, 1978), a weighted backprojection method, and a radial post correction method (Tanaka, 1983 and 1984). Counts in the specified region-of-interest in phantom images reconstructed by the radial postcorrection, weighted backprojection, and postcorrection methods were more strongly affected by inaccurately detected contours than were counts derived from images reconstructed by the precorrection method.

Body Surface Area↗
PubMed1985

Taxonomic studies on the Mycobacterium tuberculosis series.

Numerical classification of slowly growing mycobacteria, including 159 strains received as Mycobacterium tuberculosis, M. bovis, M. africanum, and M. microti, was carried out using 88 characters, and the following results were obtained. 1) All 159 strains received as M. tuberculosis, M. bovis, M. africanum, and M. microti formed one cluster, and no clear-cut differentiation among four species was achieved. These four species should be reduced to one species, M. tuberculosis. 2) Within the cluster, two subclusters appeared, with a number of strains located outside the subclusters. One subcluster was composed, except for two strains, of only M. tuberculosis strains, and another of M. bovis and M. africanum strains only. The subclusters were regarded as subspecies tuberculosis and subspecies bovis, respectively. M. africanum was regarded as a synonym of M. bovis, i.e., a niacin-positive variety of M. bovis (subsp. bovis). 3) An intermediate subcluster was observed outside the M. tuberculosis and M. bovis subclusters. This may be regarded as intermediate between the two subspecies, tuberculosis and bovis. 4) In the last two decades, the characteristics of M. tuberculosis strains isolated from patients seemed to be approaching those of M. bovis strains. The recently isolated strains showed stronger arylsulfatase activity and lower resistance to thiophene-2-carboxylic acid hydrazide than the strains isolated 16 to 19 years ago.

Arylsulfatases↗
PubMed1985

[Three-dimensional image processing for analysis of ventricular wall motion].

Three-dimensional data processing was developed for single photon computed tomographic imaging of the multigated blood pool with Tc-99m labelled red blood cells. A gamma camera (ZLC-7500; Siemens) was rotated from the left posterior oblique (LPO 45 degrees) to the right anterior oblique (RAO 45 degrees) projections at intervals of 180 degrees/32. Data were collected at each part for one to two minutes, and the number of gates per beat was 12 to 20, depending on the patient. Three-dimensional transaxial images of the heart were reconstructed by the filtered back projection method without attenuation correction. A Shepp & Logan filter was used for the convolution filter. Short-axial images were reconstructed from the transaxial images. Using the equicount level method, the contours of both ventricles at each short-axial cross-section image were determined automatically with 50% levels of the maximum counts. Each contour line was smoothed to the fifth order of Fourier function after conversion from (x-y) coordinates to (r-theta) polar coordinates with respect to the center of the area. Each contour line, converted again into (x-y) coordinates, was drawn successively on a color CRT at constant intervals and inclinations in order to display the ventricles three-dimensionally. It is possible to display simultaneously on a CRT the right and left ventricles or two types of cardiac disease. It is also possible to depict superimposed images of end-diastolic and end-systolic ventricles. Three cases including a normal control, one with old inferior infarction and one with hypertrophic cardiomyopathy (HCM) were examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Hypertrophic↗