Adaptively-weighted total-variation (AwTV) in a prototype 4D digital tomosynthesis system for fast and low-dose target localization

Sunghoon Choi, Sooyeul Lee, Young Nam Kang, Scott S. Hsieh, Hee Joung Kim

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

Abstract

On-board 4D cone-beam CT (CBCT) imaging using a linear accelerator (LINAC) is recently favored scanning protocol in image guided radiotherapy, but it raises the problems of excessive radiation dose. Alternatively, the 4D digital tomosynthesis (DTS) has been introduced for small-sized target localization, such as pancreas, prostate, or partial breast scan, which does not require a full 3D information. However, conventional filtered back-projection (FBP) reconstruction method produces severe aliasing artifacts due to sparsely sampled projections measured in each respiration phase within a limited angle range. This effect is even more severe when the LINAC gantry sweep speed is too fast to sufficiently cover the respiratory gating phase. Previous studies on total-variation (TV) minimization-based reconstruction framework would be an alternative approach to solve this problem, however, it presents the loss of sharpness during the iterations. In this study, we adopted an adaptively-weighted TV (AwTV) scheme which penalizes the images after the TV optimization. We introduced a look-up table which contains all possible weighting parameters during each iteration step. As a result, the proposed AwTV method provided better image quality compared to the conventional FBP and adaptive steepest descent-projection onto convex set (ASD-POCS) frameworks, showing higher structural similarities (SSIM) by factor of 1.12 compared to FBP and less root-mean-square error (RMSEs) by factor of 1.06 compared to ASD-POCS. The horizontal line profile of the spherical target inserted in the moving phantom showed that the images from FBP and ASD-POCS provided severe aliasing artifact and smoothed pixel intensities, but proposed AwTV scheme reduces the aliasing artifact while maintaining the object's sharpness. In conclusion, the proposed AwTV method has a potential for low-dose and faster 4D-DTS imaging, which indicates an alternative option to 4D-CBCT for small region target localization.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2019
Subtitle of host publicationPhysics of Medical Imaging
EditorsTaly Gilat Schmidt, Guang-Hong Chen, Hilde Bosmans
PublisherSPIE
ISBN (Electronic)9781510625433
DOIs
StatePublished - 2019
EventMedical Imaging 2019: Physics of Medical Imaging - San Diego, United States
Duration: Feb 17 2019Feb 20 2019

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume10948
ISSN (Print)1605-7422

Conference

ConferenceMedical Imaging 2019: Physics of Medical Imaging
CountryUnited States
CitySan Diego
Period2/17/192/20/19

Keywords

  • 4D tomosynthesis
  • Low-dose image reconstruction
  • Modified AwTV

ASJC Scopus subject areas

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

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