The present invention relates to the art of x-ray imaging. It finds particular application in connection with radiography and fluoroscopy and will be described with reference thereto.
Radiographic images have traditionally been recorded on photographic film, which is ordinarily mounted in contact with one or more intensifying screens. The screen-film combination is housed in a cassette, which can be placed in a Bucky, filmer, wall mount, or other desired location. After the screen-film combination is exposed to x-radiation, the film is processed in a series of chemical solutions which produce a human readable image. Although film based systems are well known and have been used for many years, these systems have various drawbacks. The need to process the film delays image availability, introduces variables that can negatively impact image quality, and introduces additional handling, service and cost. The resultant image is in analog form; a separate digitizing step is required to convert the image to digital form.
Storage phosphor screen cassettes have also been used to produce radiographic images for example as disclosed in U.S. Pat. No. 5,072,118 to Konno. These systems use a reusable phosphor to retain an x-ray image, and a laser scanning device to create a digital representation of the image. Because one screen is required for each exposure, phosphor screen systems are limited to radiology. The laser scanning step can also impact image quality and requires additional handling, service, and cost.
Other systems include an image intensifier tube which produces an amplified, visible image, and a television or video camera. The camera acquires the image as a single image for spot radiography or as a continuing image for fluoroscopy. These systems tend to be large and heavy, thus limiting positioning flexibility, and generally have insufficient resolution for radiographic applications.
More recently, digital radiography systems have been developed. These systems typically include a flat panel image detector which includes a scintillator layer and an addressable silicon detector array. Each of the elements in the array convert the light detected by it into an electrical charge. This charge is converted into an equivalent digital signal for further processing and storage. One such image detector is disclosed in U.S. Pat. No. 5,117,114, Street, et al., issued May 26, 1992. Other image detectors do not include a scintillator layer; the detectors convert incident radiation into an electrical charge using a selenium photoconductor layer on top of a microcapacitor matrix. Such detectors are disclosed, for example in U.S. Pat. Nos. 5,331,179 and 5,319,206 to Lee, et al. In either case, the image detector is connected to a power supply or other source of power. Similarly, the image detector input/output lines are connected to an image processor. Yet other flat panel image detectors are known in the art and are readily available.
Digital radiography (DR) systems facilitate the production of direct, digital x-ray image information. This digital information is readily transferred to picture archival and communications systems (PACS) and other computer networks. A drawback to existing digital radiography systems, however, is that the power and I/O connections to the image detector are accomplished using wiring such as cables. This cabling restricts the physical placement of the detector. Provisions for accommodating the cabling must be provided, and the technologist must also take care in placing the wires relative to the patient and the x-ray image. Further, existing x-ray systems may be poorly suited to accepting the requisite power and signal cabling, thus limiting the utility of the DR systems in upgrade or retrofit applications.