Photon-counting detector computed tomography: iodine density versus virtual monoenergetic imaging of pancreatic ductal adenocarcinoma

CT (EID-CT), which down-weights low-energy photons, PCD-CT counts photons equally across the entire X-ray energy spectrum, thereby increasing the iodine signal.Moreover, since the energy information of human organs primarily resides within the relatively low-energy X-ray spectrum, PCD-CT improves soft tissues contrast.Setting the low energy threshold slightly above electronic noise levels effectively minimizes noise.Additionally, PCD-CT's smaller detector pixel size, compared to EID-CT, enhances spatial resolution.Combined with improved iodine contrast, this can enhance the detectability of small objects [7,8].This may be particularly significant for detecting PDAC in the PVP, where the attenuation differences between pancreatic parenchyma and the tumor are less pronounced compared to the LAP [5].Furthermore, PCD-CT obtains spectral information from every scan because the energy of each detected photon is registered and binned.This energy information can be utilized to generate virtual monoenergetic images (VMIs), and for material decomposition, such as generating material density iodine (MD-iodine) images [9].