In many cases, like cardiac CT, the area of interest is just a relatively small region within the larger body. "It was realized long before that one could reduce the radiation dose by sending X-rays just through the region of interest from different directions, and then reconstruct that region from resultant local data," said Wang.
Depending upon the algorithm used, the resulting images can, to different degrees, portray sharp borders or edges from tissue or bone within the region of interest but cannot show X-ray linear attenuation coefficients accurately. "This has been known for decades as the 'interior problem'," said Wang.
A method known as lambda tomography addresses the interior problem by producing changes in the density of the image. "However, physicians need quantitative images, and hence lambda tomography has not been clinically used," said Wang.
His group at Virginia Tech, in collaboration with Professor Yangbo Ye at the University of Iowa, developed the now patented "interior tomography" method for interior reconstruction of a region of interest image to replace lambda tomography. "We assume a known sub-region within the region of interest such as an air gap, a blood area, or an implant in the heart. With a known sub-region, we can solve the interior problem in a theoretically exact and mathematically stable fashion we can produce an accurate image!" said Wang.
Interior tomography is a theoretical breakthrough, and Wang and colleagues as well as peer groups have been developing it and publishing results. The patent application was filed in 2007. The proof of conce
|Contact: Susan Trulove|