Abstract: An X-ray three-dimensional imaging method in which the step of irradiating an object of imaging with X-rays from an X-ray tube so as to obtain a radioactivity density as an X-ray original image is performed with at least positions of X-ray irradiation changed, thus obtaining X-ray original images at respective X-ray irradiation positions; and the step of performing irradiation from an X-ray irradiation position in a specified position with respect to a certain observation point in the object is performed, so that an X-ray transmissivity obtained by dividing planar density of radioactivity of X-rays passing through an observation point by planar density of radioactivity if it is assumed that no object of imaging is present is obtained from pixels determined from positions of the irradiation position and observation point within the X-ray original image that corresponds to the irradiation position.

Abstract: An apparatus for measuring the teeth for looseness in a form of physical quantity of elasticity, viscosity and mass elements. The apparatus including a signal generator producing analog signals that have a desired frequency and waveform, a vibration driver for converting electrical signals supplied from the digital type oscillating signal generator into a mechanical vibration, an impedance head for detecting force and acceleration required to cause the teeth to oscillate, and an analysis device which takes in the data on the force and acceleration detected by the impedance head so as to obtain a physical quantity of the measured tooth.