A Solid State X-Ray Image Intensifier (SSXII)

A solid state x-ray 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 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. (Three talks at the AAPM meeting: WE-C-L 100J-3, 2007, WE-C-L 100J-4, 2007, WE-C-L 100J-6, 2007)