X-ray computed tomography (XCT) is increasingly being used for the measurement and inspection of large dense metallic engineering components. When scanning such components, the quality of the data is degraded by the presence of scattered radiation. In this work, the performance of a focused 2D anti-scatter grid (ASG) is investigated for scanning samples made from cobalt chrome and Inconel on a 450 kV cone-beam XCT system. The devised scatter correction method requires one additional scan of the sample, and for projections to be algorithmically processed prior to reconstruction. The results show that the ASG based scatter correction method increases the contrast-to-noise of the data by 14.5% and 61.5% for the cobalt chrome and Inconel samples, respectively. Furthermore, the method increases edge sharpness by 6% and 16.9% for outer and inner edges, respectively.
BS EN 16016-2:2011, Non destructive testing. Radiation methods. Computed tomography - Principle, equipment and samples, British Standards Institute, 2011.
2.
SchörnerK. Development of methods for scatter artifact correction in industrial X-ray cone-beam computed tomography. PhD Thesis. Technical University of Munich, Munich, 2012.
3.
BuckyG, Method of and apparatus for projecting Röntgen images, US Patent 1164987A, 1915.
4.
JarryGGrahamSAMoseleyDJ, et al.Characterization of scattered radiation in kV CBCT images using Monte Carlo simulations. Med. Phys.2006; 33: 4320–4329.
5.
InglebyHLippunerJRickeyDW, et al.Fast analytical scatter estimation using graphics processing units. Journal of x-ray Science and Technology2015; 23: 119–133.
6.
BhatiaNTisseurDBuyensF, et al.Scattering correction using continuously thickness-adapted kernels. NDT & E International2016; 78: 52–60.
7.
SakaltrasNPenaAMartinezC, et al.A novel beam stopper-based approach for scatter correction in digital planar radiography. Scientific Reports2023; 13.
8.
ZhuLBennettNRFahrigR. Scatter correction method for X-ray CT using primary modulation: theory and preliminary results. IEEE Transactions on Medical Imaging2006; 25: 1573–1587.
9.
MaierJSawallSKnaupM, et al.Deep scatter estimation (DSE): Accurate real-time scatter estimation for X-ray CT using a deep convolutional neural network. Journal of Nondestructive Evaluation2018; 37.
10.
SchörnerKGoldammerMStephanJ. Comparison between beam-stop and beam-hole array scatter correction techniques for industrial X-ray cone-beam CT, nuclear instruments and methods in physics research section B. Beam Interactions with Materials and Atoms2011; 269: 292–299.
11.
YanHMouXTangS, et al.Improved scatter correction in X-ray cone beam CT with moving beam stop array using Johns’ equation, Proceedings of the 10th International Meeting on Fully Three-dimensional Image Reconstruction in Radiology and Nuclear Medicine, Beijing, China, 2009.
12.
JeonDChoHLeeH, et al.A software-based method for eliminating grid artifacts of a crisscrossed grid by mixed-norm and group-sparsity regularization in digital radiography. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment2022; 1025. doi:https://doi.org/10.1016/j.nima.2021.166048
13.
AlexeevTKavanaghBMiftenM, et al.Two-dimensional antiscatter grid: a novel scatter rejection device for cone-beam computed tomography. Medical Physics2018; 45: 529–534.
14.
AltunbasCKavanaghBAlexeevT, et al.Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT. Medical Physics2017; 44: 3952–3964.
15.
AltunbasCParkYYuZ, et al.A unified scatter rejection and correction method for cone beam computed tomography. Medical Physics2021; 48: 1211–1225.
16.
CobosSFNikolovHNPollmannSI, et al.Reduction of ring artifacts caused by 2D anti-scatter grids in flat-panel CBCT. In: Proceedings of SPIE volume 11312: Medical imaging 2020: physics of medical imaging, 1131228, 16 March 2020, https://doi.org/10.1117/12.2548778.
17.
CobosSFNorleyCJNikolovHN, et al.3D-printed large-area focused grid for scatter reduction in cone-beam CT. Medical Physics2023; 50: 240–258.
18.
LiuWJFanC. Design and testing of an anti-scattering grid for medium-energy X-ray flash radiography. Applied Radiation and Isotopes2016; 107: 24–28.
19.
WatsonSAApplebyMKlingerJ, et al.Design, fabrication and testing of a large anti scatter grid for megavolt γ-ray imaging, 2005 IEEE Nuclear Science Symposium Conference Record, Fajardo, PR, USA.
20.
LazosDWilliamsonJF. Impact of flat panel-imager veiling glare on scatter-estimation accuracy and image quality of a commercial on-board cone-beam CT imaging system. Medical Physics2012; 39: 5639–5651.
21.
SchneiderCRasbandWEliceiriK. NIH Image to ImageJ: 25 years of image analysis. Nature Methods2012; 9: 671–675.
22.
ASTM E1441-11 Standard Guide for Computed Tomography (CT) Imaging, ASTM International, West Conshohocken, PA, 2011.
23.
RanaRJainAShankarA, et al.Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector. In: Proceedings of SPIE, the International Society for Optical Engineering. Fifty-seventh annual meeting of the American association of physicists in medicine, Anaheim, 2015.
