November 3, 2015 --
"CT scanners with photon-counting detectors have a number of theoretical advantages over current CT scanners, which have energy-integrating detectors," Cynthia McCollough, PhD, from the Mayo Clinic in Rochester, MN, told AuntMinnie.com. "One is that photon-counting scanners can reject electronic noise, which negatively affects image quality more and more as dose decreases. The other is that the lower energy photons -- which carry more information about iodine -- are not weighted equally with energy-integrating detectors; there the high-energy photons -- which have little iodine information -- are counted the most strongly."
There is no such weighting with photon-counting detectors, which, in fact, can be used to weight those iodine-information-carrying low-energy photons most strongly.
In their study, Munich-based presenter Ralph Gutjahr from Siemens Healthcare and colleagues from the Mayo Clinic hypothesized that the iodine contrast-to-noise ratio should be higher for the CT detector based on photon counting. A research scanner was installed last year at Mayo as part of a U.S. National Institutes of Health (NIH) bioengineering grant.
"The scanner we have won't be commercialized, but what we learn from it may open the door to a commercial system in the future," McCollough said.
The scanner yielded increased contrast-to-noise values for a given dose, the study team will report.