Monte Carlo simulation of inverse geometry x-ray fluoroscopy using a modified MC-GPU framework

Published on Mar 18, 2015in Proceedings of SPIE
路 DOI :10.1117/12.2081684
David L Dunkerley29
Estimated H-index: 29
(UW: University of Wisconsin-Madison),
Michael T. Tomkowiak7
Estimated H-index: 7
(UW: University of Wisconsin-Madison)
+ 3 AuthorsMichael A. Speidel11
Estimated H-index: 11
(UW: University of Wisconsin-Madison)
Sources
Abstract
Scanning-Beam Digital X-ray (SBDX) is a technology for low-dose fluoroscopy that employs inverse geometry x-ray beam scanning. To assist with rapid modeling of inverse geometry x-ray systems, we have developed a Monte Carlo (MC) simulation tool based on the MC-GPU framework. MC-GPU version 1.3 was modified to implement a 2D array of focal spot positions on a plane, with individually adjustable x-ray outputs, each producing a narrow x-ray beam directed toward a stationary photon-counting detector array. Geometric accuracy and blurring behavior in tomosynthesis reconstructions were evaluated from simulated images of a 3D arrangement of spheres. The artifact spread function from simulation agreed with experiment to within 1.6% (rRMSD). Detected x-ray scatter fraction was simulated for two SBDX detector geometries and compared to experiments. For the current SBDX prototype (10.6 cm wide by 5.3 cm tall detector), x-ray scatter fraction measured 2.8-6.4% (18.6-31.5 cm acrylic, 100 kV), versus 2.2-5.0% in MC simulation. Experimental trends in scatter versus detector size and phantom thickness were observed in simulation. For dose evaluation, an anthropomorphic phantom was imaged using regular and regional adaptive exposure (RAE) scanning. The reduction in kerma-area-product resulting from RAE scanning was 45% in radiochromic film measurements, versus 46% in simulation. The integral kerma calculated from TLD measurement points within the phantom was 57% lower when using RAE, versus 61% lower in simulation. This MC tool may be used to estimate tomographic blur, detected scatter, and dose distributions when developing inverse geometry x-ray systems.
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#1Michael A. Speidel (UW: University of Wisconsin-Madison)H-Index: 11
#2Michael T. Tomkowiak (UW: University of Wisconsin-Madison)H-Index: 7
Last. Tobias FunkH-Index: 10
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Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system for low dose cardiac imaging. The use of a narrow scanned x-ray beam in SBDX reduces detected x-ray scatter and improves dose efficiency, however the tight beam collimation also limits the maximum achievable x-ray fluence. To increase the fluence available for imaging, we have constructed a new SBDX prototype with a wider x-ray beam, larger-area detector, and new real-time image reconstructor. Imaging is performed with ...
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#1Bahaa Ghammraoui (FDA: Food and Drug Administration)H-Index: 10
#2R. Peng (FDA: Food and Drug Administration)H-Index: 1
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Purpose: To present upgraded versions of MC-GPU and PenEASY Imaging, two open-source Monte Carlo codes for the simulation of radiographic projections and CT. The codes have been extended with the aim of studying breast imaging modalities that rely on the accurate modeling of coherent x-ray scatter. Methods: The simulation codes were extended to account for the effect of molecular interference in coherent scattering using experimentally measured molecular interference functions. The validity of t...
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#1G Nelson (Stanford University)H-Index: 6
#2Sungwon Yoon (Varian Medical Systems)H-Index: 3
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Purpose: An improved method of image guidance for lung tumor biopsies could help reduce the high rate of false negatives. The aim of this work is to optimize the geometry of the scanning-beam digital tomography system (SBDX) for providing real-time 3D tomographic reconstructions for target verification. The unique geometry of the system requires trade-offs between patient dose, imaging field of view (FOV), and tomographic angle. Methods: Tomosynthetic angle as a function of tumor-to-detector dis...
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#1Steve BurionH-Index: 3
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Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An ...
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#1Magdalena Bazalova (Stanford University)H-Index: 15
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The scanning-beam digital x-ray (SBDX) system has been developed for fluoroscopic imaging using an inverse x-ray imaging geometry. The SBDX system consists of a large-area x-ray source with a multihole collimator and a small detector. The goal of this study was to build a Monte Carlo (MC) model of the SBDX source as a useful tool for optimization of the SBDX imaging system in terms of its hardware components and imaging parameters. The MC model of the source was built in the EGSnrc/BEAMnrc code ...
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Last. Michael S. Van Lysel (UW: University of Wisconsin-Madison)H-Index: 11
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Purpose: In this study, newly formulated XR-RV3 GafChromic庐 film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures. Methods: The film was calibrated free-in-air to air kerma levels between 15 and 1100 cGy using four moderately filtered x-ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film ...
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#1Michael A. Speidel (UW: University of Wisconsin-Madison)H-Index: 11
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Last. Michael S. Van Lysel (UW: University of Wisconsin-Madison)H-Index: 11
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Purpose: Scanning beam digital x-ray (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis at multiple planes. This study describes a tomosynthesis-based method for 3D tracking of high-contrast objects and present the first experimental investigation of cardiac catheter tracking using a prototype SBDX system. Methods: The 3D tracking algorithm utilizes the stack of regularly spaced tomosynthetic planes that are g...
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#1Andreu Badal (FDA: Food and Drug Administration)H-Index: 16
#2Iacovos S. Kyprianou (FDA: Food and Drug Administration)H-Index: 14
Last. Aldo Badano (FDA: Food and Drug Administration)H-Index: 26
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The simulation of imaging systems using Monte Carlo x-ray transport codes is a computationally intensive task. Typically, many days of computation are required to simulate a radiographic projection image and, as a consequence, the simulation of the hundreds of projections needed to perform a tomographic reconstruction may require an unaffordable amount of computing time. To speed up x-ray transport simulations, a MC code that can be executed in a graphics processing unit (GPU) was developed usin...
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#1Andreu Badal (FDA: Food and Drug Administration)H-Index: 16
#2Aldo Badano (FDA: Food and Drug Administration)H-Index: 26
Purpose: It is a known fact that Monte Carlo simulations of radiation transport are computationally intensive and may require long computing times. The authors introduce a new paradigm for the acceleration of Monte Carlo simulations: The use of a graphics processing unit (GPU) as the main computing device instead of a central processing unit (CPU). Methods: A GPU-based Monte Carlo code that simulates photon transport in a voxelized geometry with the accurate physics models fromPENELOPE has been ...
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Cited By2
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#1David L Dunkerley (UW: University of Wisconsin-Madison)H-Index: 29
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Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3-D catheter tracking. This work proposes a method of dose-reduced 3-D catheter tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. This is achieved through the selective deactivation of focal spot positions not needed for the catheter tracking task. The technique was retrospectively evaluated with SBDX detector data recorded during a phantom study. D...
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#1David L Dunkerley (UW: University of Wisconsin-Madison)H-Index: 29
#2Tobias FunkH-Index: 10
Last. Michael A. Speidel (UW: University of Wisconsin-Madison)H-Index: 11
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Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D catheter tracking. This work proposes a method of dose-reduced 3D tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. Positions in the 2D focal spot array are selectively activated to create a regionof- interest (ROI) x-ray field around the tracked catheter. The ROI position is updated for each frame based on a motion vector calculated from the two...
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