X Ray :: A solid state x-ray image intensifier

A solid-state x-ray image intensifier (SSXII), now in development, should greatly improve the spatial resolution of medical x-ray imaging.

In angiography (imaging blood vessels using higher x-ray exposures to provide a very high-quality, low-noise diagnostic image) and fluoroscopy (real-time imaging at lower x-ray exposures for image guidance) it is important to minimize the x-ray dose to the patient and to maximize the sensitivity of the detectors recording the image.

Usually an x-ray image intensifier (XII) or a flat-panel detector (FPD) is employed. These are devices used for converting the x-ray image into a digital image. The XII suffers from inherent image distortions due to the method of image intensification including susceptibility to the earth?s magnetic field. As a result, the XII is currently being replaced by the newer FPDs which overcome these distortion problems. Unfortunately the flat-panel detectors themselves suffer from excessive instrumentation noise, resulting in poor image quality at the lower x-ray exposures required for fluoroscopy. Both detectors have limited spatial resolution.

Now, scientists at the University at Buffalo are developing a solid state version of the traditional x-ray image intensifier, one which relies upon electron-multiplying charge-coupled devices (CCDs) to provide variable signal amplification in solid-state. The result should be a device which incorporates all the positive features of current state-of-the-art fluoroscopic imagers, but with minimal image distortions unaffected by magnetic fields, extremely low instrumentation noise, variable sensitivity down to very low x-ray exposures, and more than double the spatial resolution. Andrew Kuhls (atkuhls@buffalo.edu, 716-829-3595 x114), working in Professor Stephen Rudin?s medical imaging physics group, says that in-vivo testing of the new device is planned, with clinical trials to follow.

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