1. Field of the Invention
The present invention relates to a radiographic image capturing apparatus, which includes a radiation source and a radiation detector required for capturing radiographic images, and which can be carried to, e.g., a patient in order to obtain radiographic image information of the patient.
2. Description of the Related Art
In the medical field, there have widely been used radiographic image capturing apparatus, which apply radiation to a subject and guide radiation that has passed through the subject to a radiation conversion panel (radiation detector), which captures a radiographic image from such radiation. Known forms of radiation conversion panels include conventional radiation film for recording a radiographic image by way of exposure, and stimulable phosphor panels for storing radiation energy representing a radiographic image in a phosphor, and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. Radiation film with the recorded radiographic image is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image.
In an operating room or the like, for the purpose of quickly and appropriately treating patients, it is necessary to read a recorded radiographic image immediately from a radiation conversion panel after the radiographic image has been captured. As a radiation detector which meets such a requirement, there have been developed a radiation detector of a direct conversion type (electronic cassette) having a solid-state detector for converting radiation directly into electric signals, and a radiation detector of an indirect conversion type (electronic cassette) having a scintillator for temporarily converting radiation into visible light and a solid-state detector for converting such visible light into electric signals.
In recent years, there have been growing demands for capturing an image of a critically ill patient who cannot easily be moved out of his or her room and also for capturing an image in emergency in an operating room. As a result, there have been increasing needs for apparatus which allow doctors to confirm, quickly with high image quality, images that have been captured in clinical and surgical environments other than X-ray image capturing rooms.
To meet such needs, a mobile radiographic image capturing apparatus has been proposed. As the conventional technology of a mobile radiographic image capturing apparatus, for example, Japanese Laid-Open Patent Publication No. 2009-201561 discloses a mobile medical cart, and Japanese Laid-Open Patent Publication No. 2010-022731 discloses a radiographic image capturing apparatus.
The mobile medical cart in Japanese Laid-Open Patent Publication No. 2009-201561 and the radiographic image capturing apparatus in Japanese Laid-Open Patent Publication No. 2010-022731 comprise a cart unit which is movable by electric power or by hand, and a radiographic apparatus installed in the cart unit. The radiographic apparatus at least has an X-ray source, a cassette housing a stimulable phosphor panel which records radiographic image information of a subject, an image reader for reading radiographic image information from the stimulable phosphor panel in the cassette, and a battery for supplying electric power to devices. In particular, Japanese Laid-Open Patent Publication No. 2009-201561 further discloses an example which uses an electronic cassette housing a solid-state radiation detector, instead of a cassette housing a stimulable phosphor panel.
There has been developed a portable radiographic image capturing apparatus, which can be folded into a compact form in its entirety (see Japanese Laid-Open Patent Publication No. 11-104117, Japanese Laid-Open Patent Publication No. 2007-530979 (PCT), U.S. Pat. No. 4,979,198). In addition, radiation sources comprising field-electron-emission-type electron sources based on carbon nanotube (CNT) technology have also been developed (see Japanese Laid-Open Patent Publication No. 2007-103016, and AIST: Press Release, “Development of Portable X-ray Sources Using Carbon Nanostructures” [online], Mar. 19, 2009, National Institute of Advanced Industrial Science and Technology, Internet <URL:http://www.aist.go.jp/aist_j/press_release/pr2009/pr20090319/pr20090319.html> (hereinafter referred to as “Document 1”). It is expected that small-size, lightweight radiographic image capturing apparatus including radiation sources will become available in the art. Further, a portable size and high energy X-ray source was developed by using LiTaO3 that is a typical pyroelectric crystal (see “Applying Pyroelectric Crystal to Small High Energy X-Ray Source”, Advances in X-Ray Chemical Analysis, Japan, 41, 2010, pages 195-200 (hereinafter referred to as “Document 2”)).
Wireless electric power transmitting schemes are known from IEDM Plenary Talk, “Arrival of Contactless Power Transmission Sheet Expected to be Embedded in Walls and Floors, developed by the University of Tokyo” [online], Dec. 4, 2006, Internet <URL:http://techon.nikkeibp.co.jp/article/NEWS/20061204/124943/> (hereinafter referred to as “Document 3”), and Nikkei Electronics, “Development of Wireless Power Transmission Technology, a 60-W Lamp Turned on in Experiment,” Dec. 3, 2007, pages 117-128 (hereinafter referred to as “Document 4”). The process disclosed in Document 3 transmits electric power based on electromagnetic induction from a primary coil embedded in a contactless power transmission sheet. The process disclosed in Document 4 is a wireless power transmission technology based on magnetic field resonance between two LC resonators.