Patent ID: 7706498
Filing Date: 2010-04-27
Classification: A61B

Abstract:
1. An X-ray CT apparatus comprising: an X-ray data collecting system comprising an X-ray generating section configured to generate X-rays and an X-ray detecting section comprising a multiplicity of X-ray detector elements two-dimensionally arranged, facing each other across a cavity and provided rotatably around a given axis; an imaging table configured to carry a subject placed thereon through said cavity along the given axis; a scan control device configured to control said X-ray data collecting system and said imaging table to perform a first helical scan on the subject to collect projection data; an image reconstructing device configured to perform image reconstruction processing based on the collected projection data to produce a tomographic image of the subject; a cardiac motion identifying device configured to identify cardiac motion of the subject; an optimal cardiac phase setting device configured to set an optimal cardiac phase for the subject; a target position defining device configured to determine a target position to be scanned in a direction along the given axis of the subject when a cardiac phase for the subject is at the optimal cardiac phase; and a transport-starting-cardiac-phase calculating device configured to calculate a transport-starting cardiac phase corresponding to a time at which transport of said imaging table is to be started such that the target position is scanned at the optimal cardiac phase, using a cardiac cycle of the subject determined based on the identified cardiac motion, a scan start position in the subject, a transport speed of said imaging table, and an approach-run time for said imaging table, the transport-starting cardiac phase calculated according to the following equation:  where Stph denotes the transport-starting cardiac phase, Tgph denotes the optimal cardiac phase, Pm denotes the target position, Ps denotes the scan start position, Vt denotes the transport speed, Tr denotes the approach-run time, and Th denotes the cardiac cycle, and wherein said scan control device is further configured to control said imaging table to start transport of said imaging table when the cardiac phase of the subject determined based on the identified cardiac motion coincides with the calculated transport-starting cardiac phase.