MicroComputed tomography with a photon-counting X-ray detector

E. C. Frey, K. Taguchi, M. Kapusta, J. Xu, T. Orskaug, I. Ninive, D. Wagenaar, B. Patt, B. M.W. Tsui

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Scopus citations


In this work we used a novel CdTe photon counting x-ray detector capable of very high count rates to perform x-ray micro-computed tomography (microCT). The detector had 2 rows of 384 square pixels each 1 mm in size. Charge signals from individual photons were integrated with a shaping time of -60 ns and processed by an ASIC located in close proximity to the pixels. The ASIC had 5 energy thresholds with associated independent counters for each pixel. Due to the thresholding, it is possible to eliminate dark-current contributions to image noise. By subtracting counter outputs from adjacent thresholds, it is possible to obtain the number of x-ray photon counts in 5 adjacent energy windows. The detector is capable of readout times faster than 5 ms. A prototype bench-top specimen μCT scanner was assembled having distances from the tube to the object and detector of 11 cm and 82 cm, respectively. We used a conventional x-ray source to produce 80 kVp x-ray beams with tube currents up to 400 μA resulting in count rates on the order of 600 kcps per pixel at the detector. Both phantoms and a dead mouse were imaged using acquisition times of 1.8 s per view at 1° steps around the object. The count rate loss (CRL) characteristics of the detector were measured by varying the tube current and corrected for using a paralyzable model. Images were reconstructed using analytical fan-beam reconstruction. The reconstructed images showed good contrast and noise characteristics and those obtained from different energy windows demonstrated energy-dependent contrast, thus potentially allowing for material decomposition.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2007
Subtitle of host publicationPhysics of Medical Imaging
EditionPART 1
StatePublished - 2007
EventMedical Imaging 2007: Physics of Medical Imaging - San Diego, CA, United States
Duration: Feb 18 2007Feb 22 2007

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
NumberPART 1
ISSN (Print)1605-7422


OtherMedical Imaging 2007: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego, CA


  • Microcomputed tomography
  • Photon counting x-ray detector

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


Dive into the research topics of 'MicroComputed tomography with a photon-counting X-ray detector'. Together they form a unique fingerprint.

Cite this