Dr. Josh Star-Lack Profile

Dr. Josh Star-Lack

at Varex Imaging Corp

SPIE Involvement:

Author

Publications (27)

Proceedings Article | 18 October 2022 Open Access

Design and optimization of 3D VSHARP® scatter correction for industrial CBCT using the Linear Boltzmann Transport Equation

Kevin Holt, Devang Savaliya, Amy Shiroma, Martin Hu, David Nisius, Steve Hoelzer, Mingshan Sun, Don Vernekohl, Josh Star-Lack

Proceedings Volume 12304, 1230419 (2022) https://doi.org/10.1117/12.2647154

KEYWORDS: Sensors, Image segmentation, Image quality, Reconstruction algorithms, 3D image processing, Spatial resolution, Genetic algorithms, Aluminum, 3D acquisition, Physics

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We have developed VSHARP®, a suite of scatter correction solutions that have been incorporated into the commercially available cone-beam software development toolkit, CST (Varex Imaging, Salt Lake City, UT) enabling scatter correction to be applied as part of an entire CBCT reconstruction pipeline. The suite includes 2D VSHARP®, a deconvolution correction using asymmetric Gaussian kernels, 2D VSHARP-ML, a U-NET machine-learning correction, and 3D VSHARP®, a correction using a rapid finite-element Linear Boltzmann Transport Equation (LBTE) solver to estimate scatter in a manner similar to traditional stochastic Monte Carlo (MC) simulations. Of the three corrections, 3D VSHARP is the most accurate and flexible since it can be readily applied to arbitrary scanner geometries, protocols, and scan parts while the 2D VSHARP models may need to be regenerated for each configuration. On the other hand, 3D VSHARP is inherently slower since a minimum of two reconstruction passes are needed and the LBTE solver, while much faster than traditional MC, is still computationally intensive. The goal of this work was to minimize LBTE run times for (typically large) industrial datasets by optimizing parameter settings, particularly the choice of the sampling grid dimensions. This was achieved by applying a multi-objective genetic algorithm to find the Pareto front characterizing the tradeoff between speed and accuracy and identifying key operating points on the curve. Testing with 720 frames of 3720x3720 projection data to make a reconstruction volume of size 500x500x600, we found that excellent image quality can be obtained by using a coarse scatter grid size of 27x27x32 volume and 44x44 detector and a primary grid size of 246x246 x295 volume and 295x295 detector, both over 42 frames for a grand total of 21 seconds LBTE computation time. We show the Pareto characterization, as well as demonstrations of 3D VSHARP image quality with significantly reduced scatter-induced artifacts such as streaking and shading.

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Proceedings Article | 15 February 2021 Presentation + Paper

Dual energy chest x-ray for improved COVID-19 detection using a dual-layer flat-panel detector: simulation and phantom studies

Linxi Shi, N. Robert Bennett, Minghui Lu, Mingshan Sun, Jin Zhang, Josh Star-Lack, Emily Tsai, H. Henry Guo, Adam Wang

Proceedings Volume 11595, 1159528 (2021) https://doi.org/10.1117/12.2581317

KEYWORDS: Chest imaging, Sensors, Dual energy imaging, Chest, Opacity, Visualization, Switching, Sensor performance, Radiography, Bone

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Proceedings Article | 15 February 2021 Poster + Presentation + Paper

3D VSHARP®, a general-purpose CBCT scatter correction tool that uses the linear Boltzmann transport equation

Josh Star-Lack, Kevin Holt, Steve Hoelzer, Devang Savaliya, Amy Shiroma, Suman Shrestha, Eric Amusin, Don Vernekohl, David Nisius, Mingshan Sun

Proceedings Volume 11595, 115952X (2021) https://doi.org/10.1117/12.2582048

KEYWORDS: Algorithm development, 3D modeling, X-rays, X-ray detectors, X-ray computed tomography, Software development, Sensors, Photon transport, Image quality, Data acquisition

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Proceedings Article | 16 March 2020 Presentation + Paper

Projection-domain metal artifact correction using a dual layer detector

Linxi Shi, N. Robert Bennett, Josh Star-Lack, Minghui Lu, Adam Wang

Proceedings Volume 11312, 1131225 (2020) https://doi.org/10.1117/12.2547936

KEYWORDS: Image segmentation, Dual energy imaging, Scintillators, Computed tomography

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Proceedings Article | 16 March 2020 Paper

Model-based material decomposition with system blur modeling

Wenying Wang, Matthew Tivnan, Grace Gang, Yiqun Ma, Qian Cao, Minghui Lu, Josh Star-Lack, Richard Colbeth, Wojciech Zbijewski, J. Webster Stayman

Proceedings Volume 11312, 113123Q (2020) https://doi.org/10.1117/12.2549549

KEYWORDS: Systems modeling, Iodine, Scintillators, Imaging systems, X-rays, Computed tomography, Dual energy imaging

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Proceedings Article | 16 March 2020 Presentation + Paper

Comparative study of dual energy cone-beam CT using a dual-layer detector and kVp switching for material decomposition

Linxi Shi, N. Robert Bennett, Edward Shapiro, Richard Colbeth, Josh Star-Lack, Minghui Lu, Adam Wang

Proceedings Volume 11312, 1131220 (2020) https://doi.org/10.1117/12.2549781

KEYWORDS: Dual energy imaging, X-rays, Imaging systems, Prototyping, Bone

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Proceedings Article | 4 March 2019 Presentation + Paper

Dual energy imaging with a dual-layer flat panel detector

Minghui Lu, Adam Wang, Edward Shapiro, Amy Shiroma, Jin Zhang, Joachim Steiger, Josh Star-Lack

Proceedings Volume 10948, 1094815 (2019) https://doi.org/10.1117/12.2513499

KEYWORDS: Sensors, Dual energy imaging, Modulation transfer functions, Bone, X-rays, Scintillators, Calibration, Imaging systems, X-ray detectors, X-ray imaging

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Dual Energy (DE) imaging has been widely used in digital radiography and fluoroscopy, as has dual energy CT for various medical applications. In this study, the imaging performance of a dynamic dual-layer a-Si flat panel detector (FPD) prototype was characterized for dual energy imaging tasks. Dual energy cone beam CT (DE CBCT) scans were acquired and used to perform material decomposition in the projection domain, followed by reconstruction to generate material specific and virtual monoenergetic (VM) images. The dual-layer FPD prototype was built on a Varex XRD 4343RF detector by adding a 200 μm thick CsI scintillator and a-Si panel of 150 μm pixel size on top as a low energy detector. A 1 mm copper filter was added as a middle layer to increase energy separation with the bottom layer as a high energy detector. The imaging performance, such as Modulation Transfer Function (MTF), Conversion Factor (CF), and Detector Quantum Efficiency (DQE) of both the top and bottom detector layers were characterized and compared with those of the standard single layer XRD4343 RF detector. Several tissue equivalent cylinders (solid water, liquid water, bone, acrylic, polyethylene, etc.) were placed on a rotating stand, and two separate 450-projection CBCT scans were performed under continuous 120 kV and 80 kV X-ray beams. After an empirical material decomposition calibration, water and bone images were generated for each projection, and their respective volumes were reconstructed using Varex’s CBCT Software Tools (CST 2.0). A VM image, which maximized the contrast-to-noise ratio of water to polyethylene, was generated based on the water and bone images. The MTF at 1.0 lp/mm from the low energy detector was 32% and 22% higher than the high energy detector and the standard detector, respectively; the DQE of both high and low energy detectors is much lower than that of the standard XRD 4343RF detector. The CNR of water to polyethylene from the VM image improved by 50% over that from the low energy image alone at 120 kV, and by 80% at 80 kV. This study demonstrates the feasibility of using a dual-layer FPD in applications such as DE CBCT for contrast enhancement and material decomposition. Further evaluations are underway.

Proceedings Article | 9 March 2017 Paper

1D pixelated MV portal imager with structured privacy film: a feasibility study

Pavlo Baturin, Daniel Shedlock, Marios Myronakis, Ross Berbeco, Josh Star-Lack

Proceedings Volume 10132, 1013240 (2017) https://doi.org/10.1117/12.2254606

KEYWORDS: Sensors, Photons, Gold, Spatial resolution, Reflection, Scintillators, Modulation transfer functions, Quantum efficiency, Optical filters, Radio optics, Imaging systems, Amorphous silicon, Electronic components, Electronic imaging

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SPIE Journal Paper | 29 November 2016

Accuracy of patient-specific organ dose estimates obtained using an automated image segmentation algorithm

Taly Gilat Schmidt, Adam S. Wang, Thomas Coradi, Benjamin Haas, Josh Star-Lack

JMI, Vol. 3, Issue 04, 043502, (November 2016) https://doi.org/10.1117/12.10.1117/1.JMI.3.4.043502

KEYWORDS: Neck, Tissues, Bone, X-ray computed tomography, Image processing algorithms and systems, Lung, Monte Carlo methods, Computed tomography, Error analysis, Image segmentation

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Proceedings Article | 22 March 2016 Paper

Accuracy of patient specific organ-dose estimates obtained using an automated image segmentation algorithm

Taly Gilat-Schmidt, Adam Wang, Thomas Coradi, Benjamin Haas, Josh Star-Lack

Proceedings Volume 9783, 978311 (2016) https://doi.org/10.1117/12.2217374

KEYWORDS: Image segmentation, Computed tomography, Monte Carlo methods, Algorithm development, Image processing algorithms and systems, Software development, Radiation dosimetry, Lung, Ions, Brain

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Proceedings Article | 22 March 2016 Paper

Striped ratio grids for scatter estimation

Scott Hsieh, Adam Wang, Josh Star-Lack

Proceedings Volume 9783, 97830J (2016) https://doi.org/10.1117/12.2216896

KEYWORDS: Modulation, Cones, Beam analyzers, Nonlinear image processing, Image processing, X-ray computed tomography, X-ray imaging, X-ray sources, Sensors, Bone, Monte Carlo methods, Modulators, Manufacturing, Medical imaging

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Proceedings Article | 23 March 2015 Paper

Prototype 1.75 MV X-band linear accelerator testing for medical CT and industrial nondestructive testing applications

James Clayton, Daniel Shedlock, Steven Vanderet, George Zentai, Josh Star-Lack, Richard LaFave, Gary Virshup

Proceedings Volume 9438, 943813 (2015) https://doi.org/10.1117/12.2084394

KEYWORDS: Imaging systems, Prototyping, Nondestructive evaluation, X-rays, X-ray computed tomography, X band, Radiotherapy, Amorphous silicon, Metals, X-ray imaging

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Proceedings Article | 18 March 2015 Paper

Asymmetric scatter kernels for software-based scatter correction of gridless mammography

Adam Wang, Edward Shapiro, Sungwon Yoon, Arundhuti Ganguly, Cesar Proano, Rick Colbeth, Erkki Lehto, Josh Star-Lack

Proceedings Volume 9412, 94121I (2015) https://doi.org/10.1117/12.2081501

KEYWORDS: Breast, Mammography, Digital mammography, Monte Carlo methods, Sensors, Image quality, Signal detection, Signal attenuation, Image restoration, Point spread functions

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Proceedings Article | 19 March 2014 Paper

Reflection properties of scintillator-septum candidates for a pixelated MeV detector

Mihye Shin, Josh Star-Lack, Martin Janecek, Eric Abel, Daniel Shedlock, Rebecca Fahrig

Proceedings Volume 9033, 90331H (2014) https://doi.org/10.1117/12.2043281

KEYWORDS: Sensors, Reflectivity, Reflection, Interfaces, Reflectors, Glasses, Scintillators, Surface finishing, Optical properties, Polishing

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Proceedings Article | 19 March 2014 Paper

Rapid scatter estimation for CBCT using the Boltzmann transport equation

Mingshan Sun, Alex Maslowski, Ian Davis, Todd Wareing, Gregory Failla, Josh Star-Lack

Proceedings Volume 9033, 90330Z (2014) https://doi.org/10.1117/12.2043312

KEYWORDS: Monte Carlo methods, Reconstruction algorithms, Sensors, Photons, Computer simulations, Data modeling, Detection and tracking algorithms, Computed tomography, Superposition, 3D modeling

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Proceedings Article | 19 March 2014 Paper

Measurement of imaging properties of scintillating fiber optic plate

George Zentai, Arundhuti Ganguly, Josh Star-Lack, Gary Virshup, Hayley Hirsh, Daniel Shedlock, David Humber

Proceedings Volume 9033, 90333Q (2014) https://doi.org/10.1117/12.2043887

KEYWORDS: Modulation transfer functions, Imaging systems, X-rays, X-ray imaging, Fiber optics, Scintillators, Crystals, Fiber optics tests, Sensors, Copper

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Proceedings Article | 19 March 2013 Paper

Scatter correction with kernel perturbation

Josh Star-Lack, Mingshan Sun

Proceedings Volume 8668, 86681I (2013) https://doi.org/10.1117/12.2008181

KEYWORDS: Monte Carlo methods, Sensors, Computer simulations, Convolution, X-rays, X-ray computed tomography, Error analysis, Medical imaging, Scatter measurement, X-ray imaging

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Proceedings Article | 19 March 2013 Paper

User-friendly, ultra-fast simulation of detector DQE(f)

Eric Abel, Mingshan Sun, Dragos Constanin, Rebecca Fahrig, Josh Star-Lack

Proceedings Volume 8668, 86683O (2013) https://doi.org/10.1117/12.2008411

KEYWORDS: Sensors, Photons, Scintillation, Neodymium, Computer simulations, Point spread functions, Scintillators, Quantum efficiency, Particles, Modulation transfer functions

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Proceedings Article | 17 March 2011 Paper

Fast 4D cone-beam reconstruction using the McKinnon-Bates algorithm with truncation correction and nonlinear filtering

Ziyi Zheng, Mingshan Sun, John Pavkovich, Josh Star-Lack

Proceedings Volume 7961, 79612U (2011) https://doi.org/10.1117/12.878226

KEYWORDS: Reconstruction algorithms, Image quality, CT reconstruction, Nonlinear filtering, Signal to noise ratio, Data acquisition, Lung, Radiotherapy, 3D image reconstruction, Computed tomography

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Proceedings Article | 13 March 2009 Paper

Efficient scatter correction using asymmetric kernels

Josh Star-Lack, Mingshan Sun, Anders Kaestner, Rene Hassanein, Gary Virshup, Timo Berkus, Markus Oelhafen

Proceedings Volume 7258, 72581Z (2009) https://doi.org/10.1117/12.811578

KEYWORDS: Convolution, Monte Carlo methods, Sensors, Point spread functions, Atrial fibrillation, X-rays, Data modeling, Superposition, Scatter measurement, Imaging systems

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Proceedings Article | 18 March 2008 Paper

Parameter investigation and first results from a digital flat panel detector with forward bias capability

Jared Starman, Carlo Tognina, Gary Virshup, Josh Star-lack, Ivan Mollov, Rebecca Fahrig

Proceedings Volume 6913, 69130L (2008) https://doi.org/10.1117/12.772356

KEYWORDS: Photodiodes, X-rays, Sensors, Scintillators, Amorphous silicon, Diodes, Switches, X-ray detectors, CT reconstruction, Data acquisition

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Proceedings Article | 21 March 2007 Paper

Improved scatter correction for x-ray conebeam CT using primary modulation

Lei Zhu, Josh StarLack, N. Robert Bennett, Tianfang Li, Lei Xing, Rebecca Fahrig

Proceedings Volume 6510, 65101U (2007) https://doi.org/10.1117/12.713678

KEYWORDS: Modulation, Modulators, Sensors, X-ray sources, Linear filtering, X-rays, X-ray computed tomography, Copper, Image processing, Reconstruction algorithms

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Proceedings Article | 15 March 2007 Paper

Multidetector-row CT with a 64–row amorphous silicon flat panel detector

Edward Shapiro, Richard Colbeth, Earl Daley, Isaias Job, Ivan Mollov, Todor Mollov, John Pavkovich, Pieter Roos, Josh Star-Lack, Carlo Tognina

Proceedings Volume 6510, 65103X (2007) https://doi.org/10.1117/12.713682

KEYWORDS: Sensors, Scintillators, Diagnostics, Signal to noise ratio, Scanners, Ceramics, Modulation transfer functions, X-rays, Amorphous silicon, X-ray computed tomography

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Proceedings Article | 14 March 2007 Paper

A practical reconstruction algorithm for CT noise variance maps using FBP reconstruction

Lei Zhu, Josh StarLack

Proceedings Volume 6510, 651023 (2007) https://doi.org/10.1117/12.713692

KEYWORDS: Reconstruction algorithms, Sensors, X-ray computed tomography, Convolution, Detection and tracking algorithms, Modulation transfer functions, CT reconstruction, Interference (communication), Signal processing, Image filtering

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Proceedings Article | 20 April 2005 Paper

2D simulations of an inverse-geometry volumetric CT system with multiple detector arrays

Samuel Mazin, Josh Star-Lack, Taly Schmidt, Norbert Pelc

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.595947

KEYWORDS: Modulation transfer functions, Detector arrays, Sensors, Radon, Imaging systems, Reconstruction algorithms, Convolution, Computer simulations, Medical imaging, 3D vision

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Proceedings Article | 20 April 2005 Paper

MTF analysis of a prototype table-top inverse-geometry volumetric CT system

Taly Schmidt, N. Robert Bennett, Samuel Mazin, Josh Star-Lack, Edward Solomon, Norbert Pelc

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.596083

KEYWORDS: Modulation transfer functions, Sensors, Prototyping, Reconstruction algorithms, Detector arrays, X-rays, Calibration, Point spread functions, 3D metrology, Data acquisition

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Proceedings Article | 5 June 2003 Paper

Energy-dependent quantum detective efficiency (QDE) measurements of a photon-counting CdTe detector array used for the scanning-beam digital x-ray (SBDX) system

Koji Iwata, Josh Star-Lack, Edward Solomon, Joseph Heanue, Rick Walkup, Robert Melen

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.480253

KEYWORDS: Sensors, X-rays, Quantum efficiency, X-ray detectors, Detector arrays, Photodetectors, Imaging systems, Digital x-ray imaging, X-ray imaging, Photon counting

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Showing 5 of 27 publications

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