| 摘要 |
PROBLEM TO BE SOLVED: To provide a radiograph capable of automatically exposure radiographing even without separately placing a radiographic automatic exposure detector as a photodetector on a front surface of a flat panel imaging sensor. SOLUTION: A pixel area corresponding to an interest detecting site of a subject 11 is set by a detecting site setter 29, and a radiographic density is set by a density setter 16a. An X-ray transmitted through the subject 11 is incident to the flat panel imaging sensor 12, and a charge signal proportional to each pixel is stored in each pixel. A gate signal is sent from a gape driver circuit 2 to the pixel, and the signal is read by an amplifier circuit 3. A pixel selector 25 selectively captures a signal of the set pixel area from an image signal from the amplifier circuit 3, and sends the signal to an adder circuit 15a. The signal is compared with the set radiographic density by a comparator 17a. When the signal exceeds the set density, a high voltage of an X-ray high voltage unit 19 is cut off by an X-ray cut-off signal generator 18a, and radiographing is finished.
|
