Biomedical subjects

M Takai

Publications and source records attributed to M Takai.

132 records · Page 8Linked to original sources

PubMedDate not supplied

Breast cancer diagnosis by laser transmission photo-scanning with spectro-analysis (report 4).

The laser transmission photo-scanning (LTPS) is a non-invasive imaging technique for breast examination that is based on the fact that tumors have a different light transmission rate than normal tissues. The LTPS equipment used in our study was improved by adopting a dual (red and infrared) beam scan method. LTPS results of 19 patients are presented here, together with their mammography results. Sixteen positive cases were detected by LTPS, while mammography yielded 15 out of 19 cases. In our study, LTPS images were similar in accuracy to those of X-ray mammography. This dual-wavelength LTPS system improved the tumor sensitivity and specificity of transmission images. It may be possible to present pathophysiological data in addition to anatomical data, to distinguish malignant from benign tumors.

Adult↗

PubMedDate not supplied

Quantitative CT for determination of thorium in thorotrast patients.

The concentrations of thorium in the liver, spleen, and their efferent lymph nodes were determined in six thorotrast patients by quantitative CT scanning. Thorium concentration per CT number was calibrated by scanning a phantom that contained a known concentration of thorium nitrate solution. The total amount of thorium determined by the quantitative CT method in the liver, spleen, and lymph nodes was compared with that determined by gamma-ray measurement of the upper abdomen using a whole body counter. A linear relationship was obtained between the amount of thorium determined by the CT method and that determined by the gamma-ray measurement method, although the correlation was not high. The quantitative CT method appears to be useful for determining, with some accuracy, the concentration of thorium in the liver, spleen, and lymph nodes of thorotrast patients.

Gamma Rays↗

PubMedDate not supplied

Construction of a laser transmission photo-scanner: pre-clinical investigation (report 2).

A prototype high-speed laser transmission photo-scanner using a 1 mm He-Ne laser beam and corresponding detector was constructed. Signals obtained from the detector were digitalized and stored in floppy disks by a micro-computer and displayed as color-coded pictures on the CRT monitor. The data were analyzed and absorption in the tissue was shown in a histogram. Breast tissue was simulated using pork, ham, lard, and cheese in a pre-clinical investigation. Normal breasts of volunteers were also examined. When disks of varying sizes were inserted into ham and cheese of various thicknesses, it was found that disks closer to the beam's point of entrance produced the best images, while disks in the center and those closer to the exit were poorly detected. Disks close to the surface were better detected than central lesions. Laser transmission images of normal breasts of twelve volunteers were symmetrical but often nonhomogeneous because of the complexity of breast tissue.

Breast↗

PubMedDate not supplied

Fundamental studies of breast tumor detection with narrow beam laser scanning (report 1).

Fundamental studies were performed in which halogen parallel lights and narrow beam He-Ne laser scanning were applied to the image diagnosis of breast lesions. The breast tissue was simulated by fresh milk as an opaque material. With halogen parallel lights, objects close to the light could not be detected, objects in the center were slightly detectable, and those close to the detector were visualized distinctly. Narrow beam scanning with He-Ne laser produced contrasting results: the closer the object was to the light, the better its detectability. However, as the diameter of the object decreased, detectability worsened. The results of the experiments indicated that small lesions in the opaque breast tissue may be detected by He-Ne laser with narrow beam scanning.

Breast Neoplasms↗

PubMedDate not supplied

Relationship of the celiac and superior mesenteric arteries to the vertebral bodies and its clinical relevance.

To determine the relationship of the origins of the celiac artery (CA) and superior mesenteric artery (SMA) to the vertebral bodies, and their distribution in males and females, we examined them quantitatively on the angiograms of 1,591 patients (male 1,003, female 588). Our results showed that the origins of the CA and SMA were highly variable: 14.0% of the CA originated beyond the extent of the lower half of T12 to the upper part of L1, and 24.7% of the SMA originated beyond the level of L1. The origin of the SMA was more variable than that of the CA (p < 0.01). The variation in the origin of the CA was not significantly different (p > 0.05) between males (13.4%) and females (15.1%), but a statistically significant difference (p < 0.01) between males (22.3%) and females (28.7%) was shown for the SMA. The distance between the origin of the two arteries was over 3 cm in six patients (0.4%). Our results provide a valuable reference for clinical practice.

Adolescent↗

PubMedDate not supplied

Promoting effects of phenobarbital on the enzyme-altered foci induced by intrahepatic gamma-ray-irradiation in the rat liver.

Radiation-induced carcinogenesis of the rat liver using iridium-192 seeds as an intrahepatic radioactive source was studied by enzyme histochemical means. Rats were divided into six groups according to various combinations of one or two iridium-192 or stainless steel seeds and whether they were given a diet containing 0.05% phenobarbital (PB) or a basal diet (BD). Each group were sacrificed at 20, 40, and 60 weeks after intrahepatic insertion of the iridium-192 or stainless steel seeds. gamma-Glutamyl transpeptidase (GGT), glucose-6-phosphatase (G6Pase), and adenosine triphosphatase (ATPase) were stained in the liver tissues, and GGT-positive foci were quantified. Liver neoplasm was not evident, but enzyme-altered foci (EAF) were induced by gamma-ray irradiation. At every point (20, 40, and 60 weeks) after the insertion of the seeds, the GGT-positive area was larger in the rats given than those given BD. Moreover, despite the iridium-192 radioactivity decay, EAF developed continuously in the rats given PB, and persisted in those given BD from 40 to 60 weeks after insertion. These results indicated that phenobarbital promotes the development of EAF initiated by irradiation, as it promotes the process of chemical carcinogenesis in the rat liver.

Adenosine Triphosphatases↗