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Title: A generalized reconstruction framework for unconventional PET systems

Abstract

Purpose: Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels. Methods: The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood-expectation–maximization. System geometry can be specified using a simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon’s algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features. Results: Application of the framework for three novel PET systems, each designed formore » a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual-pinhole half-ring insert integrated into Biograph-40: although the insert device improves image quality over conventional whole-body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual-pinhole flat-panel insert integrated into Biograph-40: preliminary results from an investigation into a modular flat-panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half-ring and flat-panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries. Conclusions: This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations.« less

Authors:
;  [1]; ; ; ;  [2]
  1. Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States)
  2. Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri 63110 (United States)
Publication Date:
OSTI Identifier:
22581318
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 8; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ALGORITHMS; BIOMEDICAL RADIOGRAPHY; COMPRESSION; COMPRESSION RATIO; CONCENTRATION RATIO; CORRECTIONS; DESIGN; IMAGE PROCESSING; IMAGES; OPTIMIZATION; PARALLEL PROCESSING; POSITRON COMPUTED TOMOGRAPHY; SIMULATION; SYMMETRY

Citation Formats

Mathews, Aswin John, E-mail: amathews@wustl.edu, Li, Ke, O’Sullivan, Joseph A., Komarov, Sergey, Wang, Qiang, Ravindranath, Bosky, and Tai, Yuan-Chuan. A generalized reconstruction framework for unconventional PET systems. United States: N. p., 2015. Web. doi:10.1118/1.4923180.
Mathews, Aswin John, E-mail: amathews@wustl.edu, Li, Ke, O’Sullivan, Joseph A., Komarov, Sergey, Wang, Qiang, Ravindranath, Bosky, & Tai, Yuan-Chuan. A generalized reconstruction framework for unconventional PET systems. United States. https://doi.org/10.1118/1.4923180
Mathews, Aswin John, E-mail: amathews@wustl.edu, Li, Ke, O’Sullivan, Joseph A., Komarov, Sergey, Wang, Qiang, Ravindranath, Bosky, and Tai, Yuan-Chuan. 2015. "A generalized reconstruction framework for unconventional PET systems". United States. https://doi.org/10.1118/1.4923180.
@article{osti_22581318,
title = {A generalized reconstruction framework for unconventional PET systems},
author = {Mathews, Aswin John, E-mail: amathews@wustl.edu and Li, Ke and O’Sullivan, Joseph A. and Komarov, Sergey and Wang, Qiang and Ravindranath, Bosky and Tai, Yuan-Chuan},
abstractNote = {Purpose: Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels. Methods: The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood-expectation–maximization. System geometry can be specified using a simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon’s algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features. Results: Application of the framework for three novel PET systems, each designed for a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual-pinhole half-ring insert integrated into Biograph-40: although the insert device improves image quality over conventional whole-body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual-pinhole flat-panel insert integrated into Biograph-40: preliminary results from an investigation into a modular flat-panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half-ring and flat-panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries. Conclusions: This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations.},
doi = {10.1118/1.4923180},
url = {https://www.osti.gov/biblio/22581318}, journal = {Medical Physics},
issn = {0094-2405},
number = 8,
volume = 42,
place = {United States},
year = {Sat Aug 15 00:00:00 EDT 2015},
month = {Sat Aug 15 00:00:00 EDT 2015}
}