CIRCULAR SOLID STATE FLAT PANEL X-RAY DETECTOR
Publication Date: 2015-Jun-10
The IP.com Prior Art Database
A solid state flat panel X-ray detector is disclosed. The detector includes a circular shape light imager panel, which has a sensing surface and a non-sensing surface. Multiple light sensitive pixels arranged on a circular silicon wafer, the sensing surface and multiple contacting traces are disposed at the back of the wafer, the non sensing surface. A scintillator is optically coupled onto the sensing surface of the light imager panel and a circuitry board reads and/or controls the light imager through the contracting traces.
The present disclosure relates generally to X-ray imaging and more particularly to a circular solid state flat panel X-ray detector.
In radiography, X-ray image detectors with square or rectangular surface areas have been widely used. Figure 1 depicts an example of pixel structure of one such conventional square or rectangular detector. The pixels are arranged in a two-dimensional array. Output of all pixels located in one column is connected through a row selective gate to a data line. A contacting finger is disposed at end of each data line that connects the data line with a readout circuitry located outside panel.
A controlling terminal of the selecting gate of all pixels in a row is connected to one scan line. Similarly controlling terminal of a reset gate of all pixels in a row is connected to one reset line. All the scan lines and the reset lines are fed into a scan logic and a reset logic respectively. On receiving scanning signal, the scan logic turns on the selecting gate of pixels of one row at a time. After readout is complete, the rest logic reset resets the pixels of one row at a time. Another conventional technique employs such scan and reset logic inside the pixel array by sharing real estate with one column of pixels.
Recent trend in X-ray imaging is replacement of Radiological Imaging Unit (RIU) or Image Intensifier with solid state flat panel detectors such as mobile C-arms. Replacing the RIU with the solid state flat panel detector is a very costly proposition. For example, a 21cm flat panel detector costs more than twice of the 9 inch RIU and the price difference between a 31cm flat panel detector and a 12 inch RIU is even larger. Major contributor to cost of the solid state flat panel detector is silicon wafer used in fabricating the flat panel detector. Therefore, though solid state flat panel detectors are preferred, cost remains a challenge.
Further, while it is highly desirable that the RIU replacement has similar field of review (FOV) and external dimensions. Desirable shape of the RIU replacement is circular because a square detector is larger in x-y dimensions for same diameter of the FOV.
A conventional technique employs a solid-body x-ray image detector with circular detector surface area. As depicted in Figure 2, such conventional technique includes a readout circuitry, 24 and a sensing area 28. The readout circuitry 24 is semi-circular, ring-shaped and is disposed adjacent to the silicon wafer in a radial direction. The sensing area 28 measures about 5mm. However, the sensing area excludes a narrow edge region.
It would be desirable to have an efficient circular solid state flat panel X-ray detector that does not exclude edge regions.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 depicts a conventional solid-body x-ray image detector with circular detector surface area.
Figure 2 depicts an example of pixel structure of conventional square...