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A new method for obtaining depth distribution of the nonlinearity parameter B/A and the frequency‐dependent attenuation coefficient is outlined. In this method, the higher frequency probe pulse wave, superposed coaxially on the lower frequency pump pulse wave, is modulated nonlinearly due to their propagation, and is received as an echo signal. The relationship between these acoustic parameters and the modulation characteristics of the probe pulse wave is derived by the division of the spectra of modulated echo signals with each other. The possibility of canceling out of error factors, such as the frequency‐dependent acoustic reflection coefficient of random scattering medium, in the above division process is discussed. A preliminary evaluation of this method is made by using an experimental system. B/A values are obtained for various kinds of sponge test targets immersed in water, n‐propyl alcohol, isopropyl alcohol, ethylene glycol, or diethylene glycol; and for agar graphite phantom.

Multifunctional logic gate devices consisting of a nanodot array are studied from the viewpoint of single electronics. In a nanodot array, the dots come in a random variety of sizes, which sometimes has a negative effect on the performance of electrical device applications. Here, this feature is used in a positive sense to achieve higher functionality in the form of flexible logic gates with low power consumption in which the variability of logic functions is guaranteed. Nanodot arrays with two input gates and one control gate in a variety of arrangements are considered, in which the two-input logic functions (such as NAND, NOR, or exclusive-OR (XOR) gates) are selected by changing the voltage applied to the control gate. To ensure the flexibility of the device, it is important to guarantee the performance with any one of the six important logic functions: NAND, AND, NOR, OR, XOR, and XNOR. We ran a selection simulation using a nanodot array consisting of six nanodots with different dot arrangements to clarify the relation between the variability of the logic functions and the dot arrangements.

Liver demonstrates a heterogeneous (18)F fluoro-2-deoxy-D: -glucose ((18)F-FDG) uptake pattern and sometimes shows an abnormally increased uptake even when there is no malignant tissue. The aim of this study was to evaluate the relationships of liver (18)F-FDG uptake as related to physical factors, fatty liver, blood glucose (BG), and other biochemical data.(18)F-FDG positron emission tomography (PET) imaging was performed in 101 consecutive subjects for cancer screening. Multiple stepwise regression analysis was used to define the best predictors of the liver standardized uptake value (SUV) among height, weight, waist circumference, body mass index (BMI), systolic and diastolic blood pressure, BG and other biochemical data, i.e., aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, total cholesterol, high-density lipoprotein cholesterol, triglycerides, total protein, total bilirubin, and alkaline phosphatase. Furthermore, we evaluated the association between liver (18)F-FDG uptake and the metabolic syndrome.The independent factors for increased liver (18)F-FDG uptake (mean SUVor = 2) were BMI (P0.0001), triglycerides (P = 0.0007), and high-density lipoprotein cholesterol (P = 0.0013). Other factors were not significantly associated with liver (18)F-FDG uptake. In addition, the liver (18)F-FDG uptake of metabolic syndrome subjects was significantly higher than that of a non-metabolic syndrome subjects.BMI was the strongest determinant of liver (18)F-FDG uptake, and the liver (18)F-FDG uptake of metabolic syndrome subjects was significantly higher than that of non-metabolic syndrome subjects. This result suggests that a subject with a high liver (18)F-FDG uptake should be screened for the metabolic syndrome.

Ultrasonic B-mode images, as the output of diagnostic ultrasonic imaging systems, are the results caused by acoustic properties inside the human body and a number of acoustic or electrical processings by equipment. In order to estimate a B-mode image and extract useful information for diagnosis, research in the new methods is necessary so that B-mode images can be analyzed quantitatively. For the first step in the development of such new techniques, a simulation model for B-mode imaging was developed. This paper describes the structure of the simulation model studied, and presents some calculated B-mode images.

The present invention relates to an ultrasonic examination apparatus which transmits ultrasonic waves into a body to be examined and receives the echo signals therfrom for examination of the inside of the body. The ultrasonic examination apparatus measures acoustic characteristics such as nonlinear parameter within the body using tha fact that the characteristic of the reception ultrasonic wave from the inside of the body is varied in accordance with variation of the characteristics within the body. The ultrasonic examination apparatus has first and second ultrasonic transducers for transmitting first ultrasonic pulse and second ultrasonic pulse, respectively. The frequency of the second ultrasonic pulse from the second ultrasonic transducer is higher than that of the first ultrasonic transducer. The first and second ultrasonic pulses are superimposed and transmitted into the body. The phase relation of the first and second ultrasonic pulses is controlled so that the modulation characteristic of the reception signal based on the non-linear effect assumes the maximum.

An application of nonlinear effect to ultrasonic pulse reflection method is described. With this method, higher frequency probe pulse wave and lower frequency large pressure amplitude pump pulse wave are transmitted along the axis of a coaxially arranged probe transducer and a pump transducer, and are superposed in the propagation medium by precisely controlling the relative phase of these pulses. Frequency characteristics of a nonlinearly modulated probe pulse wave are analyzed, and center frequency shift and change in group delay are obtained. These experimental values are evaluated by a simple analytical method.

An ultrasonic tomographic diagnosis apparatus suitable for skin disease displays a first ultrasonic tomographic image (12) of an object of a fairly broad area, wherein sizes in depthwise direction (X in FIG. 1) displayed in an enlarged scale in relation to sizes in a direction (Y in FIG. 1) on the skin surface, and further a second ultrasonic tomographic image (13) of an object wherein sizes in depthwise direction and sizes in the direction on the skin surface are displayed in substantially proportional to actual size relations, for a selected part marked by a marker (14) on the first tomographic image (12). While specific embodiments of the invention have been illustrated and described herein, it is realized that modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all modifications and changes as fall within the true spirit and scope of the invention.

The modulation characteristics of a high frequency probe pulse, superposed on a large amplitude low frequency pump pulse, are analyzed in a medium modeled with a frequency dependent attenuation coefficient. The influence of a probe pulse with finite amplitude and duration on these modulation characteristics is simulated by numerical computation. An algorithm estimating the local distribution of acoustic parameters in a random scattering medium is derived.

The method for measuring the distribution of the attenuation coefficient and the nonlinearity characteristic, using the nonlinear effect in superposed probe and pump pulse waves, is described. The relationship between these acoustic parameters, the measured crossing frequency (ωx) and the slope of the depth dependence of ω x is also described. The experimental result of using a pig liver as a lossy medium is reported.