During the last decade, I’ve noticed a tremendous increase in imaging technology. One more example is the use of “ghost images” created by X-rays interacting with solids to image solids, including tissue. This was reported by a team led by Ling-An Wu, a physicist in the Chinese Academy of Sciences in Beijing, and described here.
Image quality is competitive with other technology, but the radiation dose per image is less than current high-resolution technology. Although the acquisition time is not addressed, it seems probable that it would be longer than current medical X-ray technology (less than one minute).
Ghost image hardware is simple. A radiation source is focused on a patterned filter that absorbs and scatters X-rays and then on to the sample and detector. Wu’s team used sandpaper for the patterned filter and a single-pixel detector. Single-pixel detectors provide images ranging from black to white. Individually, the images are not very interesting or useful, but if the patterned filter is rotated from image to image, computers can see a pattern and construct the image of the sample. Ghost imaging dates back about 20 years for IR and visible illumination (https://en.wikipedia.org/wiki/Ghost_imaging), and should not be confused with ghost imaging in information technology for backing up hard drives, etc.
To improve the speed or resolution, a multipixel detector should be chosen. Alternatively, the patterned filter could be recorded in high-resolution instruments and then used with a single-pixel detector.
Wu recognizes that the value of ghost imaging technology depends on reducing the total X-ray dose and providing useful image quality in a practical turnaround time. Time and dose might not be as important in other applications, particularly in fund-limited labs that can tolerate longer time-to-answer and low-sample throughput.
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected]
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