| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain required S/N on projection data even if a subject is substantially photographed in a low dose mode in an X-ray CT apparatus. SOLUTION: This X-ray CT apparatus is provided with an X-ray tube 40 and an X-ray detector array 70 opposed to each other with the subject 100 placed between, and recomposes a CT tomographic image of the subject on the basis of projection data collected from the X-ray detector array. The X-ray CT apparatus is further provided with an integrator 1 integrating the detection output of an X-ray detector XDi and capable of changing the integrating time constant, an X-ray dose estimating means 2 for estimating an X-ray dose per picture element inputted to the X-ray detector XDi, on the basis of specified set information related to a scanning plan, and a control means 3 for changing the integrating time constant of the integrator in a diminishing direction when the estimated X-ray dose is less than a specified threshold TH.</p> |
