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Ludewig E, Rowan C, Schieder K, Frank B. An Overview of Factors Affecting Exposure Level in Digital Detector Systems and their Relevance in Constructing Exposure Tables in Equine Digital Radiography. J Equine Vet Sci 2023; 121:104206. [PMID: 36621702 DOI: 10.1016/j.jevs.2022.104206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
The aim of this review is to describe the steps of constructing exposure tables for use of digital detector systems (DRx) in equine practice. Introductory, selected underlying technical aspects of digital radiography are illustrated. Unlike screen-film radiography (SFR), DRx have a uniform signal response of the detector over a large dose range. This enables generation of diagnostic images from exposures that were previously nondiagnostic on SFR, thus reducing retakes. However, with decreasing detector entrance dose, image noise increasingly hampers the image quality. Conversely, unlike the blackening observed on SFR, overexposures can go visibly undetected by the observer. In DRx the numeric exposure indicator value is the only dose-control tool. In digital radiography the challenge is to reduce the dose and reduce the radiation risk to staff whilst maintaining diagnostic image quality. We provide a stepwise method of developing exposure tables as tools for controlling exposure levels. The identified kVp - mAs combinations in the table are derived from the predefined exposure indicator values of the detector system. Further recommendations are given as to how the exposure indicator can be integrated into routine workflow for rechecking the reliability of the formerly identified settings and how these tables might serve a basis for further reduction of the exposure level. Detector quantum efficiency (DQE) is an important parameter of assessing performance of an imaging system. Detectors with higher DQE can generate diagnostic images with a lower dose, thus having a greater potential for dose reduction than detectors with low DQE.
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Affiliation(s)
- Eberhard Ludewig
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Conor Rowan
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Katrin Schieder
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ben Frank
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
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Mageed M, Dyab S, Swagemakers JH, Gerlach K. The impact of different bone tracers and acquisition times on image quality of equine bone scintigraphy. Vet Radiol Ultrasound 2022; 63:593-600. [PMID: 35666549 DOI: 10.1111/vru.13107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The impact of different acquisition times (AqT) and technetium-99 m-labeled (99m Tc) diphosphonates on the image quality of bone scintigraphy is poorly documented in horses. The aim of this prospective experimental study was to evaluate the impact of varying 99m Tc-disphosphonates and AqT on semiquantitative and qualitative image parameters of bone scintigraphy in horses. Twenty-four horses undergoing bone scintigraphy were divided equally and randomly into methylene- (MDP), hydroxymethylene- (HDP), and dicarboxypropane diphosphonate (DPD) groups. Lateral scintigraphic images of the antebrachium were obtained 3 h post 99m TC-diphosphonate injection using three AqT (60, 90, 120 s). The images were analyzed semiquantitatively using the bone-soft tissue ratio (B:ST), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image contrast. Furthermore, a blinded qualitative analysis was performed using a visual grading analysis. The results showed that DPD images had a significantly higher B:ST ratio than MDP images (P < .01) but not HDP images in all AqT (P > .08). However, DPD and HPD images acquired at 60 s had significantly higher CNR (P < .05) than those acquired at 90 and 120 s. The qualitative analysis revealed no significant differences between 99m Tc-diphosphonates at AqT 60 and 90 s. However, MDP images acquired at 120 s had significantly lower image quality compared to DPD and HDP (P = .01 and .03, respectively). In conclusion, the bone tracers affected the semiquantitative image parameters but not the qualitative analysis findings. Increasing AqT did not necessarily improve the image quality. Therefore, decreasing the AqT enabled a reduction in personnel radiation exposure.
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Affiliation(s)
- Mahmoud Mageed
- Tierklinik Lüsche GmbH, Independent researcher, Bakum, Germany
| | | | | | - Kerstin Gerlach
- Department for Horses, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
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Shimbo G, Tagawa M, Matsumoto K, Tomihari M, Yanagawa M, Ueda Y, Inokuma H, Miyahara K. Three-legged radiographic view for evaluating cranioventral lung region in standing calves with bovine respiratory disease. J Vet Med Sci 2018; 81:120-126. [PMID: 30531129 PMCID: PMC6361651 DOI: 10.1292/jvms.18-0333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study proposed a novel radiographic positioning in order to image the cranioventral lung region using a portable X-ray unit and digital radiography system. In the novel position,
calves were restrained in a chute and a unilateral forelimb was pulled cranially with the contralateral forelimb tied to the chute; the forelimbs were then spread cranio-caudally as in a
scissor position (Three-legged view: TL view). In a preliminary study, we applied the TL view for imaging of 14 clinically healthy calves. In a clinical study, accuracy in detecting
cranioventral lung lesions was compared between the standard standing view and the TL view for 19 calves, which were culled from herd; the results of postmortem examination were used as gold
standard. Seven evaluators independently interpreted the images. The median (range) number of trials and the time for obtaining optimal position were 2 (1–7) and 263 sec (105–488),
respectively in 14 healthy calves. Calves thicker than approximately 40 cm were not considered candidates for TL view in this setting because of difficulty in restraint and the low output of
the portable X-ray unit. The TL view improved the detection of consolidation in the cranioventral lung region, compared with the standard view. The TL view was considered an optional view
when the cranioventral lung region was an area of interest, because this view was relatively easy to perform and required a small number of personnel, even for large calves.
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Affiliation(s)
- Genya Shimbo
- Veterinary Medical Center, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Michihito Tagawa
- Veterinary Medical Center, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Kotaro Matsumoto
- Department of Veterinary Medicine, Division of Clinical Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Mizuki Tomihari
- Department of Veterinary Medicine, Division of Clinical Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Masashi Yanagawa
- Department of Veterinary Medicine, Division of Clinical Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Yuki Ueda
- Veterinary Medical Center, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Hisashi Inokuma
- Department of Veterinary Medicine, Division of Clinical Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Kazuro Miyahara
- Veterinary Medical Center, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
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Diagnostic Imaging of the Lower Respiratory Tract in Neonatal Foals. Vet Clin North Am Equine Pract 2015; 31:497-514. [DOI: 10.1016/j.cveq.2015.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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