We propose to develop an optically-coupled CCD x-ray system using a novel, optical multiplexing imaging technique. A group of binary optical lenses is used instead of an image intensifier to couple the latent image from a scintillating screen to the CCD. Low readout-rate CCD imagers can be effectively used for fluoroscopic imaging without increasing detector noise. This technology overcomes disadvantages of conventional image intensifier fluoroscopy, including: aberrations, noise, contrast degradation, and restricted dynamic range and spatial resolution of radiographic images. Our preliminary studies indicate that the proposed system, operating at 16 frames per second, is x-ray quantum noise limited. Compared with an image intensifier and conventional fluoroscopy, it offers improved spatial resolution (up to 14 lp/mm), better contrast sensitivity, and a wider dynamic range (12-14 bit) for the same radiation dose. We plan to build a laboratory prototype and measure modulation transfer function, signal-to-noise ratio, detective quantum efficiency and lesion detectability, as a function of frame rate. We will conduct contrast-detail analysis, needle biopsy, and observer studies, comparing the proposed system to image intensifier fluoroscopic systems and stereotactic CCD imaging systems. The proposed technology is applicable to radiologic interventional procedures requiring real-time imaging. It is ideally suited for low Kvp image-guided breast interventional procedures such as: (1) preoperative lesion localization; (2) image-guided needle biopsy; (3) galactography; (4) real-time imaging to evaluate implant envelopes; and potentially, (5) real-time image-guided local interstitial therapy, such as lesion ablation. At higher Kvp it is applicable to certain interventional procedures such as; (1) fluoroscopic evaluation and guide biopsy of pulmonary lesions; (2) gastrointestinal fluoroscopic procedures such as endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiography (PTHC), and biliary drainage procedures; (3) musculoskeletal interventional procedures such as facet joint anesthetic blocks, bone biopsy, and vertebroplasty; and (4) neurologic interventional procedures requiring high resolution, real-time fluoroscopic imaging such as cerebral aneurysm occlusion.
| Jiang, Hangyi; Chen, Wei R; Liu, Hong (2002) Techniques to improve the accuracy and to reduce the variance in noise power spectrum measurement. IEEE Trans Biomed Eng 49:1270-8 |
