Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study
Background: To quantify image quality and radiation doses in regions adjacent to and distant from bismuth shields in computed tomography (CT). Methods: An American College of Radiology accreditation phantom with four solid rods embedded in a water-like background was scanned to verify CT number (CTN...
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| Format: | Article |
| Language: | English |
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Elsevier
2019-10-01
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| Series: | Biomedical Journal |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2319417017301403 |
| _version_ | 1811279552124551168 |
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| author | Ying-Lan Liao Nan-Ku Lai Yeu-Sheng Tyan Hui-Yu Tsai |
| author_facet | Ying-Lan Liao Nan-Ku Lai Yeu-Sheng Tyan Hui-Yu Tsai |
| author_sort | Ying-Lan Liao |
| collection | DOAJ |
| description | Background: To quantify image quality and radiation doses in regions adjacent to and distant from bismuth shields in computed tomography (CT). Methods: An American College of Radiology accreditation phantom with four solid rods embedded in a water-like background was scanned to verify CT number (CTN) accuracy when using bismuth shields. CTNs, image noise, and contrast-to-noise ratios (CNRs) were determined in the phantom at 80–140 kVp. Image quality was investigated on image portions in the zones adjacent (A zone) to and distant (D zone) from a bismuth shield. Surface radiation doses were measured using thermoluminescent dosimeters. Streak artefacts were graded on a 3-point-scale. Results: Changes in CTN caused by a bismuth shield resulted in changes in X-ray spectra. CTN changes were more apparent in the A zone than in the D zone, particularly for a low tube voltage. The degrees of CTN changes and image noise were proportional to the thickness of the bismuth shields. A 1-ply bismuth shield reduced surface radiation doses by 7.2%–15.5%. The overall CNRs were slightly degraded, and streak artefacts were acceptable. Conclusions: Using a bismuth shield could result in significant CTN changes and perceivable artefacts, particularly for a superficial organ close to the shield, and is not recommended for quantification CT examinations or follow-up CT examinations. Keywords: Computed tomography, Radiation protection, Bismuth shielding, Quantification analysis, Image quality |
| first_indexed | 2024-04-13T00:56:36Z |
| format | Article |
| id | doaj.art-8d8b2bc88c974f28bf6fdb1b5cf4c0c7 |
| institution | Directory Open Access Journal |
| issn | 2319-4170 |
| language | English |
| last_indexed | 2024-04-13T00:56:36Z |
| publishDate | 2019-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Biomedical Journal |
| spelling | doaj.art-8d8b2bc88c974f28bf6fdb1b5cf4c0c72022-12-22T03:09:38ZengElsevierBiomedical Journal2319-41702019-10-01425343351Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom studyYing-Lan Liao0Nan-Ku Lai1Yeu-Sheng Tyan2Hui-Yu Tsai3Health Physics Division, Institute of Nuclear Energy Research, Taoyuan, TaiwanDepartment of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan; School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, TaiwanDepartment of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan; School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, TaiwanInstitute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan; Corresponding author. Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan.Background: To quantify image quality and radiation doses in regions adjacent to and distant from bismuth shields in computed tomography (CT). Methods: An American College of Radiology accreditation phantom with four solid rods embedded in a water-like background was scanned to verify CT number (CTN) accuracy when using bismuth shields. CTNs, image noise, and contrast-to-noise ratios (CNRs) were determined in the phantom at 80–140 kVp. Image quality was investigated on image portions in the zones adjacent (A zone) to and distant (D zone) from a bismuth shield. Surface radiation doses were measured using thermoluminescent dosimeters. Streak artefacts were graded on a 3-point-scale. Results: Changes in CTN caused by a bismuth shield resulted in changes in X-ray spectra. CTN changes were more apparent in the A zone than in the D zone, particularly for a low tube voltage. The degrees of CTN changes and image noise were proportional to the thickness of the bismuth shields. A 1-ply bismuth shield reduced surface radiation doses by 7.2%–15.5%. The overall CNRs were slightly degraded, and streak artefacts were acceptable. Conclusions: Using a bismuth shield could result in significant CTN changes and perceivable artefacts, particularly for a superficial organ close to the shield, and is not recommended for quantification CT examinations or follow-up CT examinations. Keywords: Computed tomography, Radiation protection, Bismuth shielding, Quantification analysis, Image qualityhttp://www.sciencedirect.com/science/article/pii/S2319417017301403 |
| spellingShingle | Ying-Lan Liao Nan-Ku Lai Yeu-Sheng Tyan Hui-Yu Tsai Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study Biomedical Journal |
| title | Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study |
| title_full | Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study |
| title_fullStr | Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study |
| title_full_unstemmed | Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study |
| title_short | Bismuth shield affecting CT image quality and radiation dose in adjacent and distant zones relative to shielding surface: A phantom study |
| title_sort | bismuth shield affecting ct image quality and radiation dose in adjacent and distant zones relative to shielding surface a phantom study |
| url | http://www.sciencedirect.com/science/article/pii/S2319417017301403 |
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