Radiation imaging apparatus

#1. Field of the Invention

#The present invention relates to a radiation imaging apparatus having an electronic cassette and an imaging stand that holds the electronic cassette.

#2. Description Related to the Prior Art

#For more complete understanding of the present invention, and the advantage thereof, reference is now made to the subsequent descriptions taken in conjunction with the accompanying drawings, in which:

#FIG. 1 is an explanatory view showing schematic structure of an X-ray image capturing system;

#FIG. 2 is a perspective view of an electronic cassette and a multi connector;

#As shown in FIG. 1, an X-ray image capturing system 10 is constituted of an X-ray generating apparatus 11, an X-ray imaging apparatus 12, and a console 13. The X-ray generating apparatus 11 is provided with an X-ray source 14 for applying X-rays to a patient P, a source controller 15 for controlling the X-ray source 14, and an exposure switch 16 for issuing an X-ray emission command to the source controller 15. The X-ray imaging apparatus 12 is provided with an electronic cassette 17 and an imaging stand 18. The electronic cassette 17 receives the X-rays having passed through the patient P and produces an X-ray image. The imaging stand 18 holds the electronic cassette 17 in such a position as to be opposed to the patient's body portion to be examined.

#The X-ray source 14 has an X-ray tube 14a for emitting the X-rays and a collimator 14b for limiting an X-ray irradiation field of the X-ray tube 14a. The X-ray tube 14a has a cathode being a filament for emitting thermoelectrons, and an anode (target) for radiating the X-rays by collision of the thermoelectrons emitted from the cathode. The target is a disk-shaped rotating anode in which rotation moves focus of the collision with the thermoelectrons in circumferential orbit to disperse heat production from the focus. The collimator 14b is composed of four X-ray shielding lead plates disposed on each side of a rectangle so as to form an irradiation opening in its middle through which the X-rays propagate. Changing the positions of the lead plates can vary the size of the irradiation opening to limit the X-ray irradiation field.

#As shown in FIG. 2, the electronic cassette 17 is composed of an FPD 20 and a flat rectangular housing 21 containing the FPD 20. The housing 21 is approximately the same size as a film cassette and an IP cassette, and, for example, is 17 inches by 14 inches identical in size to the IP cassette of a half size. The housing 21 is provided at its top surface with an irradiation surface 22 to which the X-rays are applied. The irradiation surface 22 is made of an X-ray transparent material such as carbon to prevent attenuation of the X-rays to be incident on the FPD 20.