Today we have issued the 100th license! The licenses have been issued to academic researchers all over the world, from China (38 licenses), USA (30), South Korea (12), France (5), Germany (3), UAE (2), Pakistan (2), and 1 each from Canada, Netherlands, UK, Switzerland, Taiwan, Saudi Arabia, Baku Azerbaijan, and Australia. We are very grateful for the support by and collaboration with Siemens during the development. We are pleased that our work is directly helping other groups research activities and looking forward to seeing their presentation and papers somewhere. It would be great if you keep us posted with your progress, once it is published.
Congrats to Ken Taguchi and colleagues on the publication of their journal paper entitled, “Model-based pulse pileup and charge sharing compensation for photon counting detectors: A simulation study.” The model-based algorithm is called PCP for Pulse-pileup and Charge sharing comPensation. The paper can be accessed from here (it is an open access, thanks to JHU).
The main contribution of this paper is as follows.
(1) This is the first model-based method to compensate for both charge sharing and pulse pileup simultaneously.
(2) The study showed that 15% count-loss would result in significant biases when the spectral distortion due to pulse pileup is left uncorrected for. It is not sufficient to take into account a loss of count due to pulse pileup and spectral distortion due to charge sharing.
(3) The biases observed in a small portion of sinograms will be spread to the entire CT images via the image reconstruction process.
Editorial on photon counting CT published in January 2022 IEEE TRPMS issue
Congrats to Ken Taguchi and Jan S. Iwanczyk on the publication of their journal paper entitled, “Assessment of multi-energy inter-pixel coincidence counters at the presence of charge sharing and pulse pileup: A simulation study.” The paper can be accessed from here (it is an open access, thanks to JHU).
The main contribution of this paper is as follows. (1) We used Monte Carlo (MC) simulation to compare the performance of MEICC with those of various competing methods such as analog charge summing (ACS), digital count summing (DCS), one coincidence counter (1CC), and the conventional pulse height analysis. (2) Our study showed that MEICC provided the best normalized Cramér–Rao lower bounds for all of the spectral tasks at all of the count rates (except that ACS had a better result at a few ultra-low-count rates).
A bug in script_workflow_PcTK.m has been corrected. The latest version is ver 1.03a and is included in PcTK release version 3.24a. The corrected parts concern how to initialize the matrix. We appreciate Shengzi Zhao of Tsinghua University for his help.
We are very excited that our photon counting CT book has finally been released! A total of 21 chapters written by excellent authors outline the state of the art and futuristic visions of various topics from detectors/ASICs to algorithms to clinical applications. The three editors including me as well as the chapter authors are very proud of the scientific quality and the practical value of the book. A copy is available at the following links.
Part I Spectral, Dual-Energy CT: Clinical Perspective and Applications
Chapter 1 Spectral Imaging Technologies and Apps and Dual-Layer Detector Solution by Nadav Shapira, Yoad Yagil, Naor Wainer, and Ami Altman
Chapter 2 Clinical Applications of Dual Energy CT in Neuroradiology by Rajiv Gupta, Maarten Poirot, and Rick Bergmans
Chapter 3 Clinical Perspective on Dual Energy Computed Tomography by Charis McNabney, Shamir Rai, and Darra T. Murphy
Part II Spectral, Photon-Counting CT: Clinical Perspective and Applications
Chapter 4 Imaging of the Breast with Photon-Counting Detectors by Stephen J. Glick and Bahaa Ghammraoui
Chapter 5 Clinical Applications of Photon-Counting Detector Computed Tomography by Shuai Leng, Shengzhen Tao, Kishore Rajendran, and Cynthia H. McCollough
Chapter 6 Clinical Perspectives of Spectral Photon-Counting CT by Salim Si-Mohamed, Loic Boussel, and Philippe Douek
Chapter 7 Spectral CT Imaging Using MARS Scanners by Aamir Raja, et al
Chapter 8 Advances in and Uses of Contrast Agents for Spectral Photon Counting Computed Tomography by Johoon Kim, Pratap C. Naha, Peter B. Noël, and David P. Cormode
Chapter 9 Clinical Applications of Spectral Computed Tomography: Enabling Technique for Novel Contrast Development and Targeting Imaging? by Thorsten Fleiter
Part III Photon-Counting Detectors for Spectral CT
Chapter 10 X-Ray Detectors for Spectral Photon Counting CT by Ira Blevis
Chapter 11 Spectral Performance of Photon-Counting X-Ray Detectors: How Well Can We Capture the Rainbow? by Peter Trueb, Pietro Zambon, and Christian Broennimann
Chapter 12 Photon Counting Detectors Viewed as Nonlinear, Shift-Variant Systems by Thomas Koenig
Chapter 13 Signal Generation in Semiconductor Detectors for Photon-Counting CT by Xiaochun Lai, Liang Cai, Kevin Zimmerman, and Richard Thompson
Chapter 14 Application Specific Integrated Circuits (ASICs) for Spectral Photon Counting by Chris Siu, Conny Hansson, and Krzysztof Iniewski
Chapter 15 ChromAIX: Energy-Resolving Photon Counting Electronics for High-Flux Spectral CT by Roger Steadman, Christoph Herrmann, and Amir Livne
Chapter 16 Modeling the Imaging Performance of Photon Counting X-Ray Detectors by Jesse Tanguay and Ian Cunningham
Chapter 17 Design Considerations for Photon-Counting Detectors: Connecting Detector Characteristics to System Performance by Scott S. Hsieh
Congrats to Ken Taguchi on the publication of his journal paper entitled, “Assessment of Multi-energy inter-pixel coincidence counters (MEICC) for charge sharing correction or compensation for photon counting detectors with boxcar signals.” The paper can be accessed from here and will be included in the special issue on photon counting CT.
The contribution of this paper is as follows. (1) We proposed the use of boxcar signals for high spatial resolution tasks and flat-field signals for low resolution tasks. (2) We studied the effect of cross-boundary charge sharing with NxN super-pixels using Monte Carlo (MC) simulation and an analytical counting model. (3) Our study using boxcar signals showed that MEICC with 225-µm pixels performed comparably to the current PCD with 450-µm pixels in general. We will continue to develop and assess the MEICC design. Stay tuned.
The MC program used in this paper is the stochastic version of Photon Counting Toolkit (PcTK) developed in the previous MEICC study, which has been upgraded for this study by including (1) both boxcar signals and flat-field signals and (2) NxN super-pixel measurements.
A bug in function sup_offdiag has been fixed with version 3.24. Please contact us if you already have an older version of PcTK and need the revised sup_offdiag.p only. We appreciate Minjae Lee of Yonsei University for letting us know the problem.
Congrats to Ken Taguchi on the publication of his journal paper entitled “Multi-energy inter-pixel coincidence counters for charge sharing correction and compensation in photon counting detectors.” The paper can be accessed from here.
In this paper, we proposed a novel detector design to tackle charge sharing problems and the performance assessment using a new Monte Carlo (MC) simulator found it very effective. It was very encouraging so that we have decided to continue to put our efforts for studying and further developing the MEICC design. Stay tuned.
The MC program used in this paper (outlined in Sec. 2.2) is essentially a stochastic version of Photon Counting Toolkit (PcTK). It cascades the following five processes: (1) Photon generation with randomized energies and time intervals for a Poisson distribution, (2) charge sharing based on a randomized location and interaction and detection processes, (3) pulse train generations with electronic noise, (4) comparator signal generation by pulse height analyzers with set energy thresholds, and (5) counting and coincidence processing.
