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Tanaka N, Yoon Y. Effect of anti-scatter grids on the image improvement factor in digital radiography for various phantom thicknesses and irradiation fields. Phys Eng Sci Med 2023; 46:1187-1192. [PMID: 37336831 DOI: 10.1007/s13246-023-01285-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 05/22/2023] [Indexed: 06/21/2023]
Abstract
Digital radiography (DR) is used to acquire digital images with a consistent image brightness under different exposures and in the presence of various anti-scatter grids. This study effectively evaluates the image improvement factor and the conventional physical imaging properties, such as grid selectivity, contrast improvement ratio, and grid exposure factor. Various grids and acrylic phantoms of thicknesses 20 cm and 12 cm were used in this evaluation to simulate the pelvis and lumbar spine, and the cervical spine, respectively. Applied irradiation fields were adjusted according to the simulated body parts. Eight grids (four at 40 cm-1 strip frequency with grid ratios of 6:1, 8:1, 10:1, and 12:1, and four at 60 cm-1 strip frequency with grid ratios of 8:1, 10:1, 12:1, and 14:1) were used in this study. The grid selectivity, contrast improvement ratio, and grid exposure factor increased with higher grid ratios. At a constant grid ratio, these three parameters exhibited higher values at lower strip frequency (40 cm-1) than at higher strip frequency (60 cm-1). The change in the image improvement factor of the simulated cervical spine with respect to the grid was smaller than those of the simulated pelvis and lumbar spine. Our results suggested that the image improvement factor is a useful index for selecting grids according to object thickness at a constant exposure in DR systems.
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Affiliation(s)
- Nobukazu Tanaka
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Yongsu Yoon
- Department of Multidisciplinary Radiological Science, The Graduate School of Dongseo University, Busan, Republic of Korea
- Center for Radiological Environment & Health Science, Dongseo University, Busan, Republic of Korea
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Sayed M, Knapp KM, Fulford J, Heales C, Alqahtani SJ. The principles and effectiveness of X-ray scatter correction software for diagnostic X-ray imaging: A scoping review. Eur J Radiol 2023; 158:110600. [PMID: 36444818 DOI: 10.1016/j.ejrad.2022.110600] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 10/17/2022] [Accepted: 11/06/2022] [Indexed: 11/18/2022]
Abstract
PURPOSE An anti-scatter grid is often used in X-ray radiography to reduce the scattered X-rays generated from the patient. However, the presence of a grid means the patient dose subsequently increases. Recently,severalmanufacturers have developedsoftwarethat is capable of correctingfor scattered X-rays withouttheuse ofa conventional grid. This scoping review aims to systematically map the research assessing scattering correction software and to identify any existing knowledge gaps. METHODS This scoping review involved conducting a systematic search in PubMed, Scopus, and Web of science to reveal studies that were relevant to the research question. Articles published between 01.01.2000 and 31.12.2021 examining X-ray scatter correction software for X-ray imaging were included. A part of the PRISMA model and PICO framework were utilised to establish eligibility criteria. A structured summary table was utilised to extract data from the selected articles. RESULTS In this scoping review, 20 years of literature in X-ray conventional radiography. 11 articles were included in the data synthesis. The study populations of the included studies were varied: patients, image quality phantoms and anatomical phantoms. The clinical applications of X-ray scatter correction software were found to be limited to specific body parts (cervical spine, chest, shoulder, lumbar spine, hip and pelvis). The scatter correction software appears to be effective in terms of image quality and in reducing the radiation dose. However, the conventional grid still provides a higher image quality. CONCLUSIONS X-ray scatter correction software can be effective and provides potentialbenefits for some circumstances or clinical scenarios.
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Affiliation(s)
- Mohammad Sayed
- Diagnostic Radiology Department, College of Applied Medical Sciences, Najran University, Najran 61441, Saudi Arabia; Department of Medical Imaging, College of Medicine and Health, University of Exeter, St Luke's Campus, Heavitree Road, Exeter EX1 2LU, UK.
| | - Karen M Knapp
- Department of Medical Imaging, College of Medicine and Health, University of Exeter, St Luke's Campus, Heavitree Road, Exeter EX1 2LU, UK.
| | - Jon Fulford
- Medical School, University of Exeter, Medical School Building, St Luke's Campus, Magdalen Road, Exeter EX1 2LU, UK.
| | - Christine Heales
- Department of Medical Imaging, College of Medicine and Health, University of Exeter, St Luke's Campus, Heavitree Road, Exeter EX1 2LU, UK.
| | - Saeed J Alqahtani
- Diagnostic Radiology Department, College of Applied Medical Sciences, Najran University, Najran 61441, Saudi Arabia.
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Tanaka N, Kuroyanagi H. Combination system in advanced image processing for improving image contrast and a conventional row-ratio grid for an indirect flat-panel detector system: An experimental study. Phys Med 2020; 74:40-46. [PMID: 32413514 DOI: 10.1016/j.ejmp.2020.04.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/03/2020] [Accepted: 04/21/2020] [Indexed: 11/18/2022] Open
Abstract
Conventional grids with high grid ratios are not ideal for use in bedside radiography because of the difficulty in maintaining the required alignment. To address this issue, the potential usefulness of a combination system that employs removal processing software for scattered radiation and a conventional grid with a low grid ratio (3:1) for an indirect-conversion-type flat-panel detector system was evaluated by measuring image quality and observer performance. The hypothetical grid ratios for the software were 2:1, 3:1, 6:1, 8:1, and 10:1. The scatter fraction of the combination system was lower than that of the software alone. Significant improvement was observed in the effect of scattered radiation removal up to a hypothetical software grid ratio of 6:1. However, the Wiener spectrum increased (radiographic noise degraded) with an increase in the hypothetical grid ratio. The contrast ratios of the combination system were improved compared to those of the software alone for anthropomorphic chest radiographs. An observer test was also conducted using the contrast-detail phantom. The combination system indicated higher low-contrast detectability compared to the software alone, although there were no statistical differences between the hypothetical grid ratios of 6:1, 8:1, and 10:1 in all combinations of the software alone and the combination system. We concluded that a combination system with software that uses a hypothetical grid ratio of 6:1 or more and a 3:1 conventional grid would be more useful for reducing the scattered radiation component compared to the software alone with a hypothetical higher grid ratio for thicker objects.
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Affiliation(s)
- Nobukazu Tanaka
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Hiroyuki Kuroyanagi
- FUJIFILM Medical Co., Ltd., 2-26-30 Nishiazabu, Minato-ku, Tokyo 106-0031, Japan
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Geso M, Alghamdi SS, Shanahan M, Alghamdi S, Mineo R, Aldhafery B. Information Loss Via Visual Assessment of Radiologic Images Using Modified Version of the Low-Contrast Detailed Phantom at Direct DR System. J Med Imaging Radiat Sci 2017; 48:137-143. [DOI: 10.1016/j.jmir.2017.02.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 01/21/2017] [Accepted: 02/14/2017] [Indexed: 11/29/2022]
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Monte Carlo simulation-based feasibility study of novel indirect flat panel detector system for removing scatter radiation. Phys Med 2016; 32:182-7. [DOI: 10.1016/j.ejmp.2015.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 11/11/2015] [Accepted: 11/22/2015] [Indexed: 11/18/2022] Open
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Tang H, Tong D, Dong Bao X, Dillenseger JL. A new stationary gridline artifact suppression method based on the 2D discrete wavelet transform. Med Phys 2015; 42:1721-9. [PMID: 25832061 DOI: 10.1118/1.4914861] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In digital x-ray radiography, an antiscatter grid is inserted between the patient and the image receptor to reduce scattered radiation. If the antiscatter grid is used in a stationary way, gridline artifacts will appear in the final image. In most of the gridline removal image processing methods, the useful information with spatial frequencies close to that of the gridline is usually lost or degraded. In this study, a new stationary gridline suppression method is designed to preserve more of the useful information. METHODS The method is as follows. The input image is first recursively decomposed into several smaller subimages using a multiscale 2D discrete wavelet transform. The decomposition process stops when the gridline signal is found to be greater than a threshold in one or several of these subimages using a gridline detection module. An automatic Gaussian band-stop filter is then applied to the detected subimages to remove the gridline signal. Finally, the restored image is achieved using the corresponding 2D inverse discrete wavelet transform. RESULTS The processed images show that the proposed method can remove the gridline signal efficiently while maintaining the image details. The spectra of a 1D Fourier transform of the processed images demonstrate that, compared with some existing gridline removal methods, the proposed method has better information preservation after the removal of the gridline artifacts. Additionally, the performance speed is relatively high. CONCLUSIONS The experimental results demonstrate the efficiency of the proposed method. Compared with some existing gridline removal methods, the proposed method can preserve more information within an acceptable execution time.
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Affiliation(s)
- Hui Tang
- Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096, China; Key Laboratory of Computer Network and Information Integration (Southeast University), Ministry of Education, Nanjing 210000, China; Centre de Recherche en Information Biomédicale sino-français, Laboratoire International Associé, Inserm, Université de Rennes 1, Rennes 35000, France; and Southeast University, Nanjing 210000, China
| | - Dan Tong
- Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096, China
| | - Xu Dong Bao
- Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096, China
| | - Jean-Louis Dillenseger
- INSERM, U1099, Rennes F-35000, France; Université de Rennes 1, LTSI, Rennes F-35000, France; Centre de Recherche en Information Biomédicale sino-français, Laboratoire International Associé, Inserm, Université de Rennes 1, Rennes 35000, France; and Southeast University, Nanjing 210000, China
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Chan CTP, Fung KKL. Dose Optimization in Lumbar Spine Radiographic Examination by Air Gap Method at CR and DR Systems: A Phantom Study. J Med Imaging Radiat Sci 2015; 46:65-77. [PMID: 31052066 DOI: 10.1016/j.jmir.2014.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/13/2014] [Accepted: 08/08/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This study aims at investigating the feasibility of replacing an antiscatter grid with an air gap to achieve dose reduction for lumbar spine radiography while retaining image quality at an acceptable diagnostic level. METHODS Frontal and lateral projections of lumbar spine radiographic examinations were performed on an anthropomorphic phantom. Nongrid images of both the computed radiography (CR) and digital radiography (DR) systems with air gap thickness ranging from 0 to 25 cm were produced and compared with their corresponding grid images. Dose measurements using thermoluminescent dosimeters at the ovary and testes regions of the phantom were conducted. The image quality of all the images was evaluated by five radiographers using image quality score and visual grading analysis tests. Data on dose measurements and image quality tests were input for statistical analysis. The dose area product (DAP) of all the examinations was recorded and input for the computation of effective doses using a PC-based Monte Carlo program (PCXMC 2.0; STUK, Helsinki, Finland). RESULTS Significant dose reduction effects on the ovaries of 60.2%-74.1% and 55.1%-73.3% were found, respectively, at the frontal and lateral projections of nongrid lumbar spine examinations compared with their corresponding grid ones in both the CR and DR systems. Results on the image quality score and visual grading analysis tests showed that nongrid images with 10-cm and 5-cm of air gap thicknesses respective to the frontal and lateral images of the lumbar spine were rated with the highest scores. In general, a dose reduction effect using the air gap method was found to be more pronounced in the CR system compared with the DR system. Nevertheless, the CR system delivered a 2.4-4.5 times higher ovary dose respective to the frontal and lateral projections of lumbar spine examinations compared with the DR system. CONCLUSIONS Ten and 5 centimeters were found to be the optimal air gap thicknesses respective to the frontal and lateral lumbar spine radiographic examinations of the tested Rando phantom (Alderson Laboratories, Stamford, CT) in both the CR and DR systems. Significant dose reduction effects on both the ovary and testes regions of the nongrid examinations were shown. The effective dose computed from PCMCX 2.0 reflected that the risk of cancer induction was halved when an antiscatter grid was replaced by the nongrid method with an optimal air gap thickness in the tested examinations. Further reduction on cancer risk could be achieved by using DR instead of the CR system.
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Affiliation(s)
- Charles T P Chan
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Karl K L Fung
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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Moore CS, Wood TJ, Avery G, Balcam S, Needler L, Smith A, Saunderson JR, Beavis AW. Investigating the use of an antiscatter grid in chest radiography for average adults with a computed radiography imaging system. Br J Radiol 2015; 88:20140613. [PMID: 25571914 DOI: 10.1259/bjr.20140613] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate via simulation a proposed change to clinical practice for chest radiography. The validity of using a scatter rejection grid across the diagnostic energy range (60-125 kVp), in conjunction with appropriate tube current-time product (mAs) for imaging with a computed radiography (CR) system was investigated. METHODS A digitally reconstructed radiograph algorithm was used, which was capable of simulating CR chest radiographs with various tube voltages, receptor doses and scatter rejection methods. Four experienced image evaluators graded images with a grid (n = 80) at tube voltages across the diagnostic energy range and varying detector air kermas. These were scored against corresponding images reconstructed without a grid, as per current clinical protocol. RESULTS For all patients, diagnostic image quality improved with the use of a grid, without the need to increase tube mAs (and therefore patient dose), irrespective of the tube voltage used. Increasing tube mAs by an amount determined by the Bucky factor made little difference to image quality. CONCLUSION A virtual clinical trial has been performed with simulated chest CR images. RESULTS indicate that the use of a grid improves diagnostic image quality for average adults, without the need to increase tube mAs, even at low tube voltages. ADVANCES IN KNOWLEDGE Validated with images containing realistic anatomical noise, it is possible to improve image quality by utilizing grids for chest radiography with CR systems without increasing patient exposure. Increasing tube mAs by an amount determined by the Bucky factor is not justified.
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Affiliation(s)
- C S Moore
- 1 Radiation Physics Department, Queen's Centre for Oncology and Haematology, Castle Hill Hospital, Hull and East Yorkshire Hospitals NHS Trust, Hull, UK
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Comparative Study Between Mobile Computed Radiography and Mobile Flat-Panel Radiography for Bedside Chest Radiography. Invest Radiol 2014; 49:1-6. [DOI: 10.1097/rli.0b013e3182a56654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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