Kenji Tanaka

Early Cancer Diagnosis through Ultrasonics

We succeeded in obtaining ultrasonic echoes from human intracranial ventricles and brain tumors, not only through the dura mater during surgical operation, but also through the skull at preoperative and postoperative examinations. In these experiments, we used 1–5 megacycle ultrasound and A‐Scope presentation. We found, among other things, that an echo from the ventricle wall pulsates slowly and rhythmically with synchronization to each heartbeat. Furthermore, we succeeded in detecting echoes from various abdominal organs and tumors through the skin, and found that the echoes reflected from the bowel move in correlation to bowel peristalsis. As the echoes are so clearly perceptible, we are now engaged in developing an “ultrasono‐tomography” for a horizontal section of the human head or abdomen by plan‐position indication; such a tomograph cannot be obtained by any other penetration‐method including x‐ray. In thoracic examination also, we have made achievements not only in ultrasonic diagnosis of breast tu...

Diagnosis of Brain Tumor Using Ultrasound

Since the first report by DUSSIK (1942) the problem of the application of ultrasound in neurosurgery has been studied by FRENCH et colI. (1950, 1951), BOLT & RUETER (1951), LEKSELL (1955), GORDON (1959), JEFFERSON (1959), DE VLIEGER & RIDDER (1959),JEPPSSON (1960), LITHANDER (1961), and TAYLOR et colI. (1961). We reported on this subject at the Second I.C.A. Congress at Cambridge, Mass. in 1956 and at the Third I.C.A. Congress in Stuttgart, Germany in 1959 (TANAKA 1959). We present here an account of the ultrasonic diagnosis of brain tumors by the reflection method.

Experimental investigation of dynamics of sonoluminescing bubbles

Light scattering was carried out for a cavitation bubble trapped in a spherical flask. A He–Ne laser of 7 mW was used as the light source and the scattering angle was 90 deg. A function generator was used as the trigger source and a digital phospher oscilloscope for averaging the data. Changing the drive voltage resulted in differences in the signal waveform above and below the sonoluminescence threshold; a sonoluminescing bubble had the maximum radius greater than a dark bubble did, but showed smaller rebounds. This suggests that energy concentration is made possible by tight and symmetric collapse of the bubble. Sonoluminescence signals were also retrieved for a few hours with no laser light, and a discontinous drift was noted in the appearance time on the oscilloscope, suggesting that a bubble may have drifted in space discontinuously. [Work supported by Grant‐in‐Aid for Scientific Research, Ministry of Education, Science, and Culture, Japan.]