Patent ID: 9724051
Date: 2017-08-08
CPC Classifications: A61B

Claim:
1. A medical X-ray CT photography apparatus comprising: a support that supports an X-ray generator and an X-ray detector while the X-ray generator and the X-ray detector are opposed to each other with a subject interposed therebetween, the X-ray generator emitting an X-ray beam, the X-ray detector outputting an electric signal according to an intensity of a detected X-ray; a support retention part that journals a turning shaft provided in the support; a turning part that turns the support about the turning shaft with respect to the support retention part; a subject chair on which the subject sits; a chair moving mechanism that moves the subject chair relative to the support in at least a direction orthogonal to the turning shaft and a front-back direction of the subject; and a circuit that performs panoramic X-ray photography by controlling the chair moving mechanism and the turning part in conjunction with each other; a position of the turning shaft and a position of the support retention part are generally fixed relative to each other; in a local CT photography in which only a part of the subject is set as a CT photography area, the chair moving mechanism moving the subject chair such that the subject is positioned for the local CT photography prior to the local CT photography; in the panoramic X-ray photography, the turning part turns and moves the support so as to turn and move the X-ray generator from one side of a head of the subject to an opposite side of the head via a front of the head; the circuit controlling the chair moving mechanism in response to the turning angle of the support when the panoramic X-ray photography is performed, such that: the subject chair is moved linearly in a backward direction relative to the support while the X-ray detector goes from the opposite side of the head to the front of the head; the subject chair is moved linearly in a frontward direction relative to the support while the X-ray detector goes from the front of the head to the opposite side of the head; the chair moving mechanism linearly moving the subject chair with respect to the support turning at a fixed position; and defining that a horizontal axis is a rotation angle of the support while a vertical axis is a position of the subject chair in the front-back direction relative to the support, and a graph of a relationship between the rotation angle and the position during the panoramic X-ray photography includes a parabolic part.