title: Human Imaging With Photon Counting-Based Computed Tomography at Clinical Dose Levels: Contrast-to-Noise Ratio and Cadaver Studies.
abstract: The purpose of this work was to measure and compare the iodine contrast-to-noise ratio (CNR) between a commercial energy-integrating detector (EID) computed tomography (CT) system and a photon-counting detector (PCD) CT scanner capable of human imaging at clinical dose rates, as well as to determine clinical feasibility using human cadavers.
  
  
  
  A research dual-source PCD-CT scanner was used, where the "A" tube/detector subsystem used an EID and the "B" tube/detector subsystem used a PCD. Iodine CNR was measured in 4 anthropomorphic phantoms, simulating 4 patient sizes, at 4 tube potential settings. After biospecimen committee approval, PCD scans were performed on a fresh-frozen human head and a whole-body cadaver using clinical dose rates. Scans were repeated using the EID and identical parameters, and qualitative side-by-side comparisons were performed.
  
  
  
  For the same photon fluence, phantom measurements demonstrated a mean increase in CNR of 11%, 23%, 31%, 38% for the PCD system, relative to the EID system, at 80, 100, 120, and 140 kV, respectively. Photon-counting detector CT additionally provided energy-selective imaging, where low- and high-energy images reflected the energy dependence of the iodine signal. Photon-counting detector images of cadaveric anatomy demonstrated decreased beam hardening and calcium blooming in the high-energy bin images and increased contrast in the low-energy bins images relative to the EID images. Threshold-based PCD images were qualitatively deemed equivalent in other aspects.
  
  
  
  The evaluated research PCD-CT system was capable of clinical levels of image quality at clinical dose rates. It further provided improved CNR relative to state-of-the-art EID-CT. The energy-selective bin images provide further opportunity for dual-energy and multienergy analyses.
authors.affiliation: From the *CAMP, Technical University of Munich, Munich, Germany; †Siemens Healthcare-Imaging and Therapy Systems, Malvern, PA; Departments of ‡Radiology, and §Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN; and ∥Siemens Healthcare, Forchheim, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Gutjahr
authors.forename: Ahmed F
authors.initials: AF
authors.lastname: Halaweish
authors.forename: Zhicong
authors.initials: Z
authors.lastname: Yu
authors.forename: Shuai
authors.initials: S
authors.lastname: Leng
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yu
authors.forename: Zhoubo
authors.initials: Z
authors.lastname: Li
authors.forename: Steven M
authors.initials: SM
authors.lastname: Jorgensen
authors.forename: Erik L
authors.initials: EL
authors.lastname: Ritman
authors.forename: Steffen
authors.initials: S
authors.lastname: Kappler
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
mesh_terms: D000328:Adult; D000368:Aged; D002102:Cadaver; D002648:Child; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007231:Infant, Newborn; D007455:Iodine; D009622:Noise; D019047:Phantoms, Imaging; D017785:Photons; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine
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