book

Radiation Detectors for Medical Imaging

by Jan S. Iwanczyk

October 2015

Intermediate to advanced

351 pages

12h 21m

English

CRC Press

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CdZnTe and CdTe Crystals for Medical Applications1.1 CdTe and CdZnTe for Medical Applications1.2 CdTe and CdZnTe Materials1.3 Materials Technology1.3.1 Defect Structure of High-Purity CdTe1.3.2 Electrical Compensation1.3.3 Carrier Transport1.3.3.1 Recombination1.3.3.2 Uniform Trapping1.3.3.3 Nonuniform Trapping1.3.3.4 Carrier Transport under High Photon Flux1.4 Crystal Growth Technology1.4.1 Parasitic Nucleation1.4.2 Physical Defect Generation1.4.3 Defect Interactions1.4.4 Annealing1.4.5 Status of Crystal Growth1.5 SummaryReferences
Monte Carlo Modeling of X-Ray Detectors for Medical Imaging2.1 Introduction2.2 X-ray Detector Technologies2.2.1 Scintillator-Based Detectors2.2.2 Semiconductor-Based Detectors2.3 Modeling Approaches2.3.1 Photon–Electron Interactions2.3.2 Electron–Hole Pair Transport2.3.3 Coupled Monte Carlo Simulation2.3.4 Analytical Methods2.4 Monte Carlo Simulation of Radiation Transport2.4.1 Theory2.4.1.1 Charge Generation2.4.1.2 Recombination and Trapping2.4.2 Implementation2.4.3 Indirect Detectors2.5 Applications2.5.1 Pulse-Height Spectroscopy2.5.2 Information Factor and Detective Quantum Efficiency2.6 SummaryAcknowledgmentsReferences
Medical X-Ray and CT Imaging with Photon-Counting Detectors3.1 Introduction3.2 Historical Overview of Photon-Counting X-ray and CT Systems3.3 Advantages of PCXCT3.3.1 Electronic Noise Rejection3.3.2 SNR Improvement with Photon Energy Weighting3.3.2.1 Generalized Weighting Approach3.3.2.2 Energy Weighting in Projection X-Ray Imaging3.3.2.3 Energy Weighting in CT3.3.3 Material Decomposition3.4 Design Concepts of PCXCT3.4.1 High Demands to Clinical Imaging Systems3.4.2 Practical PCXCT Detector Configuration3.4.3 PCXCT Detector Electronics3.4.4 Material Selection for PCXCT Detectors3.4.5 Imaging Configurations3.5 PCXCT Detector Technologies3.5.1 PCXCT with Si Strip Detectors3.5.2 PCXCT with CZT and CdTe Detectors3.5.3 Medipix Detectors3.6 Problems with PCXCT and Future Developments3.6.1 Count Rate Limitations3.6.2 Low-Energy Spectral Tailing3.6.3 Intensity-Dependent Line Artifacts3.6.4 Charge Sharing3.6.5 Suboptimal Energy Resolution3.7 Feasible Clinical Application: Photon-Counting Spectral Breast CT3.8 ConclusionReferences
Pixelated Semiconductor and Parallel ASIC Design for Spectral Clinical Radiology4.1 Introduction4.2 Direct Conversion Semiconductor Sensor Development4.3 ASIC Development4.4 Module Development for Spectral Computed Tomography4.5 Detector Development for Spectral Bone Mineral Densitometry4.6 Module Development for Spectral Digital Mammography4.7 Discussion4.8 ConclusionsAcknowledgmentsReferences
Silicon Photomultipliers in Detectors for Nuclear Medicine5.1 Introduction5.2 Operation Principles5.2.1 Basic Parameters of a SiPM5.2.1.1 Gain5.2.1.2 Photon Detection Efficiency5.2.1.3 After-Pulses5.2.1.4 Optical Crosstalk5.2.1.5 Dark Noise5.2.1.6 Linearity of a SiPM5.2.1.7 Excess Noise Factor5.2.1.8 Transit Time Spread5.2.2 Digital Silicon Photomultipliers5.2.3 SiPMs in Gamma Spectrometry with Scintillators5.2.4 SiPMs in Fast Timing with Scintillators5.3 SiPMs in Medical InstrumentationsReferences
Imaging Technologies and Potential Clinical Applications of Photon-Counting X-Ray Computed Tomography6.1 Imaging Technologies6.1.1 Overall Strategy6.1.2 X-ray Beam-Shaping Filters6.1.3 Calibration and Compensation Methods6.1.4 PCD Models6.1.5 Image Reconstruction6.1.5.1 Interior Problem6.1.5.2 Spectral Data6.2 Potential Benefits and Clinical Applications6.2.1 Improved Contrast-to-Noise Ratio and Contrast of CT Images6.2.2 Dose Reductions of X-ray Radiation and Contrast Agents6.2.3 Improved Spatial Resolution6.2.4 Beam-Hardening Artifacts6.2.5 Quantitative CT and X-ray Imaging6.2.6 Accurate K-Edge Imaging6.2.7 Simultaneous Multiagent Imaging6.2.8 Molecular CT with Nanoparticle Contrast Agents and Personalized MedicineReferences
Photon-Counting Detectors and Clinical Applications in Medical CT Imaging7.1 Photon-Counting Detectors for Medical Imaging7.1.1 Direct Conversion7.1.2 Material Properties7.1.3 Candidate Materials7.1.4 Detector Fabrication and Signal Formation7.1.5 Prospects for CT Application7.2 Requirements for Photon-Counting Detectors in Medical CT Imaging7.2.1 Introduction7.2.2 Image Quality (Spatial and Contrast Resolution)7.2.3 Dose Efficiency7.2.4 Examination Time7.2.5 Rings (Bands)7.2.6 Multienergy Imaging7.3 Clinical Applications with Photon-Counting Detectors7.3.1 K-Edge Imaging7.3.2 Improved Spatial Resolution7.3.3 Dose ReductionReferences

Radiation Detection in SPECT and PET8.1 Introduction8.1.1 Historic Perspectives8.1.2 Early Developments of SPECT8.1.3 Early Developments of PET8.2 Overview8.2.1 Overview of SPECT8.2.2 Overview of PET8.3 Current Technologies in Routine Uses8.3.1 Scintillation Detectors and Pulse-Height Analysis8.3.2 SPECT8.3.2.1 Gamma Cameras8.3.2.2 Anger Position Logic8.3.2.3 Collimators8.3.3 PET8.3.3.1 Block PET Detector Modules8.3.3.2 Coincidence Detection8.3.3.3 Factors Affecting Spatial Resolution8.3.3.4 Considerations for the Scintillator8.4 Recent Advances8.4.1 SPECT8.4.1.1 Scintillators8.4.1.2 Semiconductor Detectors8.4.1.3 Photodetectors8.4.2 PET8.4.2.1 DOI Detectors8.4.2.2 TOF Detectors8.4.2.3 Silicon Photomultipliers8.4.2.4 Novel Readout Methods8.4.2.5 Waveform Sampling8.5 Future Trends and Summary8.5.1 Modular and Reconfigurable Detectors8.5.2 Application-Specific Imaging Systems8.5.3 Multimodality Imaging Systems8.5.4 SPECT and PET in Image-Guided Therapy8.5.5 SummaryReferences
Review of Detectors Available for Full-Field Digital Mammography9.1 From Analog to Digital Mammography9.2 Computed Radiography9.2.1 Dual-Side Reading9.2.2 Line-Scan Reading9.2.3 Columnar Photostimulable Phosphor9.3 Flat-Panel Detectors9.3.1 Indirect Conversion Detector9.3.1.1 TFT Readout9.3.1.2 CMOS Readout9.3.2 Direct Conversion Detectors9.3.2.1 TFT Readout9.3.2.2 Optical Readout9.3.2.3 TFT with Hexagonal Array9.4 Slot-Scanning Systems9.4.1 Indirect Conversion Approach with Tiled CCD9.4.2 Direct Conversion with Photon-Counting DetectorsReferences
Grating-Based Phase-Contrast X-Ray Imaging Technique10.1 INTRODUCTION10.2 X-ray and Its Interaction with Matter10.3 Imaging with X-ray10.4 Phase-Contrast X-ray Imaging10.5 Grating-Based PCXI10.6 Gratings10.7 Phase Stepping10.8 Image Reconstruction10.9 Optimization10.10 LimitationsReferences
Emerging Concept in Nuclear MedicineThe Voxel Imaging PET (VIP) Project11.1 Introduction11.1.1 Voxel Imaging PET (VIP)11.1.2 Pixel CdTe11.1.3 VIP-PIX Chip11.2 Image Reconstruction11.2.1 Introduction11.2.2 Simple Back-Projection11.2.3 Filtered Back-Projection11.2.4 Ordered Subset Expectation Maximization (OSEM)11.2.5 Origin Ensemble (OE) Algorithm11.2.6 Image Quality Criteria11.2.7 Available Software11.3 Voxel Imaging PET11.3.1 Current Limitations in PET Design11.3.2 Evaluation of the VIP Design11.3.3 The VIP Scatter Fraction11.3.4 VIP Counting Performance11.3.5 VIP Resolution11.3.6 VIP Image Quality11.3.7 VIP Minimum Detectable Lesion Size11.3.8 Simulation and Image Reconstruction of Real 3-D Human Head Phantom11.3.9 VIP Image Reconstruction Algorithms11.4 Positron Emission Mammography with VIP11.4.1 VIP PEM Design11.4.2 Evaluation of Imaging Performance11.5 VIP Compton Camera11.5.1 Introduction to SPECT and Compton Camera11.5.1.1 SPECT11.5.1.2 Compton Camera11.5.2 VIP Compton Camera Design11.5.3 VIP Compton Camera Performance11.5.3.1 Optimization of Design11.5.3.2 Detector Sensitivity11.5.3.3 Spatial Resolution11.5.4 VIP Compton Camera Image Reconstruction Results11.6 ConclusionAcknowledgmentsReferences

Content preview from Radiation Detectors for Medical Imaging

Preface

This book aims to provide the current status and prospective of key technologies and applications of photon-counting detectors emerging in medical imaging. Photon-counting detectors have been commonly used in nuclear medicine equipment for many years. However, the use of photon counting in x-ray imaging is very new and only possible due to recent progress in material/detector technologies combined with the availability of application-specific integrated circuits that provide very compact low-noise amplification and processing of the signal from individual detector pixels in imaging arrays. Also, novel methods for photon counting that can replace conventional photon-counting detectors utilizing photomultiplier tubes are starting to impact ...