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Daniel S, Kopp M, Vollbrecht T, Zeilinger M, Fitz T, Muttke A, Feuerlein U, Uder M, May MS. Personalization of thoracoabdominal CT examinations using scanner integrated clinical decision support systems - Impact on the acquisition technique, scan range, and reconstruction type. Eur J Radiol 2023; 167:111078. [PMID: 37688917 DOI: 10.1016/j.ejrad.2023.111078] [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: 05/07/2023] [Revised: 08/10/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023]
Abstract
OBJECTIVES This study evaluates the impact of a scanner-integrated, customized clinical decision support system (CDSS) on the acquisition technique, scan range, and reconstruction in thoracoabdominal CT. MATERIALS AND METHODS We applied CDSS in contrast-enhanced examinations of the trunk with various clinical indications on a recent scanner with the capability of dual-energy CT (DECT), anatomic landmark detection (ALD), and iterative metal-artifact reduction (MAR). Simple and comprehensive questions about the patient's breath hold capability, the anatomical region of interest, and metal implants can be answered after the localizer. The acquisition technique (single energy, SECT, or dual energy), scan range (chest-abdomen-pelvis or chest-abdomen), and reconstruction technique (with or without MAR) were then automatically adapted in the examination protocols in coherence with these selections. Retrospectively, we compared the usage rates for these techniques in 624 examinations on the study scanner with 740 examinations on a comparable scanner without CDSS. Subgroup analysis of effective dose (ED), scan duration, and image quality (IQ) was performed in the study group. RESULTS CDSS leads to an increased usage rate of DECT (64.4% vs. 2.8%) and MAR (75.4% vs. 44.0%). All scan range adaptations by ALD were successful. The resulting subjective IQ between single energy and DECT acquisitions was comparable (all p > 0.05). Scan duration was significantly longer in DECT than in SECT (16.9 s vs. 6.5 s; p < 0.001). However, the objective IQ was significantly higher in DECT (CNRD 2.1 vs. 1.8; p < 0.01), and the ED significantly lower (6.7 mSv vs. 7.6 mSv; p = 0.004). CONCLUSION CDSS for thoracoabdominal CT leads to a substantially increased usage rate of innovative techniques during acquisition and reconstruction. Patients with adapted protocols benefit from improved image quality and increased post-processing options at lower radiation doses.
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Affiliation(s)
- Sascha Daniel
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany.
| | - Markus Kopp
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Thomas Vollbrecht
- Department of Diagnostic and Interventional Radiology, University Hospital Bonn, Germany
| | - Martin Zeilinger
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Tim Fitz
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany
| | | | | | - Michael Uder
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany; Imaging Science Institute, University Hospital Erlangen, Erlangen, Germany
| | - Matthias S May
- Departement of Radiology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, 91054, Erlangen, Germany; Imaging Science Institute, University Hospital Erlangen, Erlangen, Germany
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Al Mohammad B, Alakhras MM, Reed W. Assessing the knowledge of CT radiographers regarding how CT parameters affect patient dose and image quality. Eur J Radiol 2023; 166:111023. [PMID: 37542813 DOI: 10.1016/j.ejrad.2023.111023] [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: 06/17/2023] [Revised: 07/14/2023] [Accepted: 07/31/2023] [Indexed: 08/07/2023]
Abstract
PURPOSE The objective of this study was to assess the current knowledge of CT radiographers regarding the optimization of CT parameters and their consequential effects on both patient dose and image quality. METHOD A nationwide, cross sectional study was conducted from the 2nd of January 2023 to 1st of March 2023 to evaluate CT radiographers' knowledge in managing CT parameters in Jordan. Recruitment involved convenience sampling where radiographers were invited to participate and complete the questionnaire. Descriptive statistics were used to report the normalized knowledge scores. Student's t-test and ANOVA were used to investigate and compare the outcomes between different subgroups. A forward stepwise linear regression was used to investigate the influence of a number of technologist related factors on the knowledge score. RESULTS Three hundred and fifty-seven radiographers participated in the study, with a mean knowledge score of 69.0%. Participants with an academic master's degree had a significantly higher score of 72.1% compared to the ones with a diploma degree, with a score of 66.8% (p = 0.026). No statistically significant difference was found between radiographers that received additional training and the ones that did not. Furthermore, when investigating the effects of academic education, working sector, additional training and years of experience, only education had a statistically significant impact on the knowledge score. CONCLUSION The results demonstrate that radiographers have an overall good understanding of CT parameters, with academic education having a significant influence on their performance.
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Affiliation(s)
- Badera Al Mohammad
- Department of Allied Medical Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan.
| | - Maram M Alakhras
- Department of Allied Medical Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Warren Reed
- Discipline of Medical Imaging Science, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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Kachelrieß M. [Risk-minimizing tube current modulation for computed tomography]. RADIOLOGIE (HEIDELBERG, GERMANY) 2023:10.1007/s00117-023-01160-5. [PMID: 37306750 DOI: 10.1007/s00117-023-01160-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/13/2023]
Abstract
AIM/PROBLEM Every computed tomography (CT) examination is accompanied by radiation exposure. The aim is to reduce this as much as possible without compromising image quality by using a tube current modulation technique. STANDARD PROCEDURE CT tube current modulation (TCM), which has been in use for about two decades, adjusts the tube current to the patient's attenuation (in the angular and z‑directions) in a way that minimizes the mAs product (tube current-time product) of the scan without compromising image quality. This mAsTCM, present in all CT devices, is associated with a significant dose reduction in those anatomical areas that have high attenuation differences between anterior-posterior (a.p.) and lateral, particularly the shoulder and pelvis. Radiation risk of individual organs or of the patient is not considered in mAsTCM. METHODOLOGICAL INNOVATION Recently, a TCM method was proposed that directly minimizes the patient's radiation risk by predicting organ dose levels and taking them into account when choosing tube current. It is shown that this so-called riskTCM is significantly superior to mAsTCM in all body regions. To be able to use riskTCM in clinical routine, only a software adaptation of the CT system would be necessary. CONCLUSIONS With riskTCM, significant dose reductions can be achieved compared to the standard procedure, typically around 10%-30%. This is especially true in those body regions where the standard procedure shows only moderate advantages over a scan without any tube current modulation at all. It is now up to the CT vendors to take action and implement riskTCM.
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Affiliation(s)
- Marc Kachelrieß
- Abteilung Röntgenbildgebung und Computertomographie, Deutsches Krebsforschungszentrum (DFKZ), Heidelberg, Deutschland.
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Pennati F, Salito C, Borzani I, Carrafiello G, Morlacchi LC, Vaira V, Nosotti M, Palleschi A, Aliverti A. Quantitative Multivolume Proton-Magnetic Resonance Imaging in Lung Transplant Recipients: Comparison With Computed Tomography and Spirometry. Acad Radiol 2021; 28:e297-e305. [PMID: 32653430 DOI: 10.1016/j.acra.2020.05.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/13/2020] [Accepted: 05/28/2020] [Indexed: 01/07/2023]
Abstract
RATIONALE AND OBJECTIVES Acute and chronic graft rejection remains the major problem in clinical surveillance of lung-transplanted patients and early detection of complications is of capital importance to allow the optimal therapeutic option. The aim of this study was to investigate the role of quantitative non contrast-enhanced magnetic resonance imaging (MRI) as a non-ionizing imaging modality to assess ventilation impairment in patients who have undergone lung transplantation, in comparison with quantitative computed tomography (CT) and spirometry. MATERIALS AND METHODS Ten lung-transplanted patients (39 ±12 years, forced-expiratory volume in 1 second (FEV1) = 81 ± 27%, forced vital capacity (FVC) = 87 ± 27%) were acquired in breath-hold at full-expiration and full-inspiration with 1.5T MRI and CT. Maps of expiratory-inspiratory difference in MR signal-intensity and CT-density were computed to estimate regional ventilation. Based on expiratory, inspiratory, and expiratory-inspiratory difference values, each pixel was classified as healthy (H), low ventilation (LV), air trapping (AT), and consolidation (C) and the percent extent of each class was quantified. RESULTS Overall, expiratory-inspiratory difference in MR signal-intensity correlated to CT-density (r = 0.64, p < 0.0001) and to FEV1 (ρ = 0.71, p = 0.02). The linear correlation between MRI and CT functional maps considering all the four classes is r = 0.93 (p < 0.0001). MRI percent volumes of H, AT, and C correlated to FEV1 %pred, with the highest correlation reported for AT (ρ = -0.82). CONCLUSION Results demonstrated a good agreement between MRI and CT ventilation imaging and between the corresponding percent volumes of lung damage. Quantitative MRI may represent an accurate non-ionizing imaging technique for longitudinal monitoring of lung transplant recipients.
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Ye K, Chen M, Li J, Zhu Q, Lu Y, Yuan H. Ultra-low-dose CT reconstructed with ASiR-V using SmartmA for pulmonary nodule detection and Lung-RADS classifications compared with low-dose CT. Clin Radiol 2020; 76:156.e1-156.e8. [PMID: 33293025 DOI: 10.1016/j.crad.2020.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/30/2020] [Indexed: 11/28/2022]
Abstract
AIM To evaluate the accuracy of ultra-low-dose computed tomography (ULDCT) with ASiR-V using a noise index (SmartmA) for pulmonary nodule detection and Lung CT Screening Reporting And Data System (Lung-RADS) classifications compared with low-dose CT (LDCT). MATERIALS AND METHODS Two-hundred and ten patients referred for lung cancer screening underwent conventional chest LDCT (0.80 ± 0.28 mSv) followed immediately by ULDCT (0.16 ± 0.03 mSv). ULDCT was scanned using 120 kV/SmartmA with a noise index of 28 HU and reconstructed with ASiR-V70%. The types and diameters of all nodules were recorded. The attenuation of pure ground-glass nodules (pGGNs) was measured on LDCT. All nodules were further classified using Lung-RADS. Sensitivities of nodule detection on ULDCT were analysed using LDCT as the reference standard. Logistic regression was used to establish a prediction model for the sensitivity of nodules. RESULTS LDCT revealed 362 nodules and the overall sensitivity on ULDCT was 90.1%. The sensitivity for solid nodules (SNs) of ≥1 mm diameter was 96.6% (228/236) and 100% (26/26) for SNs of ≥6 mm diameter. For pGGNs of ≥6 mm, the overall sensitivity was 93% (40/43) and 100% (29/29) for nodules with a attenuation value -700 HU or more. The agreement of Lung-RADS classification between two scans was good. On logistic regression, diameter was the only independent predictor for sensitivity of SNs (p<0.05). Diameter and attenuation value were predictors for pGGNs (p<0.05). CONCLUSION ULDCT with ASiR-V using SmartmA is suitable for lung-cancer screening in people with a BMI ≤35 kg/m2 as it has a low radiation dose of 0.16 mSv, high sensitivity for nodule detection and good performance of Lung-RADS classifications.
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Affiliation(s)
- K Ye
- Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - M Chen
- Department of Radiology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - J Li
- Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Q Zhu
- Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Y Lu
- Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - H Yuan
- Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, People's Republic of China.
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Faller FK, Mein S, Ackermann B, Debus J, Stiller W, Mairani A. Pre-clinical evaluation of dual-layer spectral computed tomography-based stopping power prediction for particle therapy planning at the Heidelberg Ion Beam Therapy Center. ACTA ACUST UNITED AC 2020; 65:095007. [DOI: 10.1088/1361-6560/ab735e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Wressnegger A, Prosch H, Moser B, Klepetko W, Jaksch P, Lambers C, Hoetzenecker K, Schestak C, De Bettignies A, Beer L, Apfaltrer G, Ringl H, Apfaltrer P. Chest CT in patients after lung transplantation: A retrospective analysis to evaluate impact on image quality and radiation dose using spectral filtration tin-filtered imaging. PLoS One 2020; 15:e0228376. [PMID: 32023294 PMCID: PMC7001933 DOI: 10.1371/journal.pone.0228376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 01/14/2020] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation. METHODS This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared. RESULTS The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGy*cm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGy*cm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73). CONCLUSIONS Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.
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Affiliation(s)
- Alexander Wressnegger
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Helmut Prosch
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Bernhard Moser
- Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - Walter Klepetko
- Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - Peter Jaksch
- Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - Christopher Lambers
- Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - Konrad Hoetzenecker
- Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - Christian Schestak
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Albert De Bettignies
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Lucian Beer
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Georg Apfaltrer
- Division of Pediatric Radiology, Department of Radiology, Medical University of Graz, Graz, Austria
| | - Helmut Ringl
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Paul Apfaltrer
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Neuroradiology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- * E-mail:
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Yurt A, Özsoykal İ, Obuz F. Effects of the Use of Automatic Tube Current Modulation on Patient Dose and Image Quality in Computed Tomography. Mol Imaging Radionucl Ther 2019; 28:96-103. [PMID: 31507141 PMCID: PMC6746012 DOI: 10.4274/mirt.galenos.2019.83723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Objectives: The frequency of abdominal computed tomography examinations is increasing, leading to a significant level of patient dose. This study aims to quantify and evaluate the effects of automatic tube current modulation (ATCM) technique on patient dose and image quality in contrast-enhanced biphasic abdominal examinations. Methods: Two different scan protocols, based on constant tube current and ATCM technique, were used on 64 patients who visited our radiology department periodically. For three patient groups with different patient size, results from two protocols were compared with respect to patient dose and image quality. Dosimetric evaluations were based on the Computed Tomography Dose Index, dose length product, and effective dose. For the comparison of image qualities between two protocols, Noise Index (NI) and Contrast to Noise Ratio (CNR) values were determined for each image. Additionally, the quality of each image was evaluated subjectively by an experienced radiologist, and the results were compared between the two protocols. Results: Dose reductions of 31% and 21% were achieved by the ATCM protocol in the arterial and portal phases, respectively. On the other hand, NI exhibited an increase between 9% and 46% for liver, fat and aorta. CNR values were observed to decrease between 5% and 19%. All images were evaluated by a radiologist, and no obstacle limiting a reliable diagnostic evaluation was found in any image obtained by either technique. Conclusion: These results showed that the ATCM technique reduces patient dose significantly while maintaining a certain level of image quality.
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Affiliation(s)
- Ayşegül Yurt
- Dokuz Eylül University Faculty of Medicine, Department of Medical Physics, İzmir, Turkey
| | - İsmail Özsoykal
- Dokuz Eylül University Faculty of Medicine, Department of Medical Physics, İzmir, Turkey
| | - Funda Obuz
- Dokuz Eylül University Faculty of Medicine, Department of Radiology, İzmir, Turkey
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Metal implants influence CT scan parameters leading to increased local radiation exposure: A proposal for correction techniques. PLoS One 2019; 14:e0221692. [PMID: 31442288 PMCID: PMC6707604 DOI: 10.1371/journal.pone.0221692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 08/13/2019] [Indexed: 12/14/2022] Open
Abstract
Metal implants not only deteriorate image quality, but also increase radiation exposure. The purpose of this study was to evaluate the effect of metal hip prosthesis on absorbed radiation dose and assess the efficacy of organ dose modulation (ODM) and metal artifact reduction (MAR) protocols on dose reduction. An anthropomorphic phantom was scanned with and without bilateral metal hip prostheses, and surface and deep level radiation doses were measured at the abdomen and pelvis. Finally, the absorbed radiation doses at pelvic and abdominal cavities in the reference, ODM, and two MAR scans (Gemstone spectral imaging, GE) were compared. The Mann Whitney-U test and Kruskal-Wallis test were performed to compare the volume CT dose index (CTDIvol) and mean absorbed radiation doses. Unilateral and bilateral metal hip prostheses increased CTDIVOL by 14.4% and 30.5%, respectively. MAR protocols decreased absorbed radiation doses in the pelvis. MAR showed the most significant dose reduction in the deep pelvic cavity followed by ODM. However, MAR protocols increased absorbed radiation doses in the upper abdomen. ODM significantly reduced absorbed radiation in the pelvis and abdomen. In conclusion, metal hip implants increased radiation doses in abdominopelvic CT scans. MAR and ODM techniques reduced absorbed radiation dose in abdominopelvic CT scans with metal hip prostheses.
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Pelegrino Bastos Maués NH, Fattori Alves AF, Menegatti Pavan AL, Marrone Ribeiro S, Yamashita S, Petean Trindade A, Mascarenhas YM, Nicolucci P, Rodrigues de Pina D. ABDOMEN-PELVIS COMPUTED TOMOGRAPHY PROTOCOL OPTIMIZATION: AN IMAGE QUALITY AND DOSE ASSESSMENT. RADIATION PROTECTION DOSIMETRY 2019; 184:66-72. [PMID: 30371858 DOI: 10.1093/rpd/ncy181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/20/2018] [Accepted: 10/19/2018] [Indexed: 06/08/2023]
Abstract
Computed tomography (CT) has a high level of sensitivity and specificity for the diagnosis and follow-up of pathologies of the abdomen-pelvis region. Some features, such as automatic tube current modulation (ATCM), permits the acquisition of quality images with low radiation doses. This study evaluated the image quality and radiation dose of abdomen-pelvis CT protocols with ATCM technique. Were performed five CT protocols using 16-slice and 64-slice scanners, an anthropomorphic phantom for dosimetric measurements, an analytical phantom and retrospective examinations for image quality analysis. Were found significant reduction in effective dose. The highest absorbed doses were found in the stomach and spleen (56.1 and 47.2 mGy, respectively). Objective parameters as noise, low contrast and spatial resolution did not significantly differ between the protocols (p > 0.05). All protocols received the range of 'Optimum/Acceptable' in patient's image quality analysis. This methodology can be reproduced in any clinical routine to optimize CT protocols.
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Affiliation(s)
| | - Allan Felipe Fattori Alves
- São Paulo State University (UNESP), Instituto de Biociências de Botucatu, Departamento de Física e Biofísica, Botucatu, São Paulo, Brazil
| | - Ana Luiza Menegatti Pavan
- São Paulo State University (UNESP), Instituto de Biociências de Botucatu, Departamento de Física e Biofísica, Botucatu, São Paulo, Brazil
| | - Sergio Marrone Ribeiro
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | - Seizo Yamashita
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | - André Petean Trindade
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | | | - Patrícia Nicolucci
- Universidade de São Paulo (USP), Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Centro de Instrumentação, Dosimetria e Radioproteção (CIDRA), Av. Bandeirantes, 3900 Bairro Monte Alegre, Ribeirão Preto, São Paulo, Brazil
| | - Diana Rodrigues de Pina
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
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Sturm A, Maaser C, Calabrese E, Annese V, Fiorino G, Kucharzik T, Vavricka SR, Verstockt B, van Rheenen P, Tolan D, Taylor SA, Rimola J, Rieder F, Limdi JK, Laghi A, Krustiņš E, Kotze PG, Kopylov U, Katsanos K, Halligan S, Gordon H, González Lama Y, Ellul P, Eliakim R, Castiglione F, Burisch J, Borralho Nunes P, Bettenworth D, Baumgart DC, Stoker J. ECCO-ESGAR Guideline for Diagnostic Assessment in IBD Part 2: IBD scores and general principles and technical aspects. J Crohns Colitis 2019; 13:273-284. [PMID: 30137278 DOI: 10.1093/ecco-jcc/jjy114] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Andreas Sturm
- Department of Gastroenterology, DRK Kliniken Berlin I Westend, Berlin, Germany
| | - Christian Maaser
- Outpatients Department of Gastroenterology, Hospital Lüneburg, Lüneburg, Germany
| | - Emma Calabrese
- Department of Systems Medicine, University of Rome, Tor Vergata, Italy
| | - Vito Annese
- Department of Gastroenterology, Valiant Clinic & American Hospital, Dubai, UAE
| | - Gionata Fiorino
- Department of Gastroenterology, Humanitas Clinical and Research Institute, Milan, Italy
| | - Torsten Kucharzik
- Department of Internal Medicine and Gastroenterology, Hospital Lüneburg, Lüneburg, Germany
| | | | - Bram Verstockt
- Department of Gastroenterology and Hepatology, University Hospitals Leuven and CHROMETA - Translational Research in Gastrointestinal Disorders, KU Leuven, Belgium
| | - Patrick van Rheenen
- Department of Paediatric Gastroenterology, Hepatology and Nutrition, University Medical Center Groningen, Groningen, The Netherlands
| | - Damian Tolan
- Clinical Radiology, St James's University Hospital, Leeds, UK
| | - Stuart A Taylor
- Centre for Medical Imaging, University College London, London, UK
| | - Jordi Rimola
- Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain
| | - Florian Rieder
- Department of Gastroenterology, Hepatology & Nutrition, Digestive Diseases and Surgery Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jimmy K Limdi
- Department of Gastroenterology, Pennine Acute Hospitals NHS Trust, Manchester; Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - Andrea Laghi
- Department of Clinical and Surgical Translational Medicine, Sapienza - University of Rome, Rome, Italy
| | - Eduards Krustiņš
- Department of Gastroenterology, Hepatology and Nutrition, Pauls Stradins Clinical University Hospital, Riga, Latvia
| | - Paulo G Kotze
- Colorectal Surgery Unit, Catholic University of Paraná PUCPR, Curitiba, Brazil
| | - Uri Kopylov
- Department of Gastroenterology, Sheba Medical Center, Sackler School of Medicine, Tel Aviv, Israel
| | - Konstantinos Katsanos
- Department of Gastroenterology and Hepatology, University and Medical School of Ioannina, Ioannina, Greece
| | - Steve Halligan
- Centre for Medical Imaging, University College London, London, UK
| | - Hannah Gordon
- Section of Gastroenterology & Hepatology, Royal London Hospital, London, UK
| | - Yago González Lama
- Department of Gastroenterology, University Hospital Puerta De Hierro, Majadahonda Madrid, Spain
| | - Pierre Ellul
- Department of Medicine, Mater Dei Hospital, Msida, Malta
| | - Rami Eliakim
- Department of Gastroenterology, Sheba Medical Center, Sackler School of Medicine, Tel Aviv, Israel
| | - Fabiana Castiglione
- Department of Clinical Medicine and Surgery, "Federico II" University of Naples, Naples, Italy
| | - Johan Burisch
- Department of Gastroenterology, North Zealand University Hospital; Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, Frederiksberg, Denmark
| | - Paula Borralho Nunes
- Department of Anatomic Pathology, Hospital Cuf Descobertas; Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Dominik Bettenworth
- Department of Medicine B, Gastroenterology and Hepatology, University Hospital Münster, Münster, Germany
| | - Daniel C Baumgart
- Division of Gastroenterology, University of Alberta, Edmonton, AB, Canada
| | - Jaap Stoker
- Department of Radiology and Nuclear Medicine, Academic Medical Center AMC, University of Amsterdam, Amsterdam, The Netherlands
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Kubo T, Ohno Kishimoto A, Togashi K. Efficiency and reproducibility in pulmonary nodule detection in simulated dose reduction lung CT images. Eur J Radiol Open 2019; 6:113-118. [PMID: 30899771 PMCID: PMC6412012 DOI: 10.1016/j.ejro.2019.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/31/2019] [Accepted: 02/05/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine the reproducibility and productivity of reduced dose chest computed tomography (CT) using a nodule detection task. Materials and methods Eighty-eight consecutive non-contrast CT examinations were performed using an automatic exposure system with a reference standard deviation of 8.5. Simulated raw data of a reduced dose scan (standard deviation at 21 and 29) were generated with a dose simulator. Original and simulated raw data were reconstructed to series of 7-mm-thick images (Original, Simulation A, Simulation B). In the first part of the reading experiment, three readers independently interpreted these images (88 cases × 3 series) and recorded the size, type, and location of the pulmonary nodules. The reading time for every case was recorded. In the second part of the experiment, the repeated interpretation of standard dose images was performed by two readers. Concordance or discordance of nodule detection between the first and the repeated reading result was assessed. Results A statistically significant difference in the detected nodule counts for lesions less than 5 mm by one reader was observed in simulation B images. Discordance of the interpretation result was found only in ground-glass nodules larger than 5 mm detected by one reader in simulation B images. There was no statistically significant difference in the reading time among the three image types. Conclusion Simulated standard deviation 21 images can reproduce the image interpretation result of original images, whereas simulated standard deviation 29 images may compromise the accuracy of nodule assessment. The effect on the reading time was not observed with dose reduction simulation.
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Affiliation(s)
- Takeshi Kubo
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Ayami Ohno Kishimoto
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kaori Togashi
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
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Alhailiy AB, Ekpo EU, Kench PL, Ryan EA, Brennan PC, McEntee M. The associated factors for radiation dose variation in cardiac CT angiography. Br J Radiol 2019; 92:20180793. [PMID: 30633548 DOI: 10.1259/bjr.20180793] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE: This study aimed to examine the associated factors for dose variation and influence cardiac CT angiography (CCTA) dose benchmarks in current CT imaging centres. METHODS: A questionnaire was distributed to CT centres across Australia and Saudi Arabia. All participating centres collected data for adults who underwent a CCTA procedure. The questionnaire gathered information about the examination protocol, scanning parameters, patient parameters, and volume CT dose index (CTDI vol) and dose-length product (DLP). A stepwise regression analysis was performed to assess the contribution of tube voltage (kV), padding time technique, cross-sectional area (CSA) of chest and weight to DLP. RESULTS: A total of 17 CT centres provided data for 423 CCTA examinations. The median CTDIvol, DLP and effective dose were 18 mGy, 256 mGy.cm and 5.2 mSv respectively. There was a statistically significant difference in DLP between retrospective and prospective ECG-gating modes (p = 0.001). Median DLP from CCTA using padding technique was 61% higher than CCTA without padding (p = 0.001). The stepwise regression showed that kV was the most significant predictor of DLP followed by padding technique then CSA while patient weight did not statistically significantly predict DLP. Correlation analysis showed a strong positive correlation between weight and CSA (r = 0.78), and there was a moderate positive correlation between weight and DLP (r = 0.42), as well as CSA and DLP (r = 0.48). CONCLUSION: Findings show radiation dose variations for CCTA. The associated factors for dose variation found in this study are scanning mode, kV, padding time technique and CSA of the chest. This results support the need to include CSA measurements in future dose survey and for setting DRLs. ADVANCES IN KNOWLEDGE: The study provides baseline information that helps to understand the associated factors for dose variations and high doses within and between centres performing CCTA.
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Affiliation(s)
- Ali B Alhailiy
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia.,2 Prince Sattam Bin Abdulaziz University , Al-Kharj , Kingdom of Saudi Arabia
| | - Ernest U Ekpo
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia
| | - Peter L Kench
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia
| | - Elaine A Ryan
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia
| | - Patrick C Brennan
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia
| | - Mark McEntee
- 1 The University of Sydney, Faculty of Health Sciences, Discipline of Medical Radiation Science , Sydney, NSW , Australia
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Gariani J, Martin SP, Botsikas D, Becker CD, Montet X. Evaluating the effect of increased pitch, iterative reconstruction and dual source CT on dose reduction and image quality. Br J Radiol 2018; 91:20170443. [PMID: 29762055 PMCID: PMC6209470 DOI: 10.1259/bjr.20170443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Objective: To compare radiation dose and image quality of thoracoabdominal scans obtained with a high-pitch protocol (pitch 3.2) and iterative reconstruction (Sinogram Affirmed Iterative Reconstruction) in comparison to standard pitch reconstructed with filtered back projection (FBP) using dual source CT. Methods: 114 CT scans (Somatom Definition Flash, Siemens Healthineers, Erlangen, Germany), 39 thoracic scans, 54 thoracoabdominal scans and 21 abdominal scans were performed. Analysis of three protocols was undertaken; pitch of 1 reconstructed with FBP, pitch of 3.2 reconstructed with SAFIRE, pitch of 3.2 with stellar detectors reconstructed with SAFIRE. Objective and subjective image analysis were performed. Dose differences of the protocols used were compared. Results: Dose was reduced when comparing scans with a pitch of 1 reconstructed with FBP to high-pitch scans with a pitch of 3.2 reconstructed with SAFIRE with a reduction of volume CT dose index of 75% for thoracic scans, 64% for thoracoabdominal scans and 67% for abdominal scans. There was a further reduction after the implementation of stellar detectors reflected in a reduction of 36% of the dose–length product for thoracic scans. This was not at the detriment of image quality, contrast-to-noise ratio, signal-to-noise ratio and the qualitative image analysis revealed a superior image quality in the high-pitch protocols. Conclusion: The combination of a high pitch protocol with iterative reconstruction allows significant dose reduction in routine chest and abdominal scans whilst maintaining or improving diagnostic image quality, with a further reduction in thoracic scans with stellar detectors. Advances in knowledge: High pitch imaging with iterative reconstruction is a tool that can be used to reduce dose without sacrificing image quality.
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Affiliation(s)
- Joanna Gariani
- 1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland
| | - Steve P Martin
- 1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland
| | - Diomidis Botsikas
- 1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland
| | - Christoph D Becker
- 1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland
| | - Xavier Montet
- 1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland
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Ju YH, Lee G, Lee JW, Hong SB, Suh YJ, Jeong YJ. Ultra-low-dose lung screening CT with model-based iterative reconstruction: an assessment of image quality and lesion conspicuity. Acta Radiol 2018; 59:553-559. [PMID: 28786301 DOI: 10.1177/0284185117726099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal-Wallis test and the Chi-square test. Results Effective doses were 61-87% lower in groups 2-5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P < 0.001). Overall image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1-3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1-4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.
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Affiliation(s)
- Yun Hye Ju
- Biomedical Engineering, Yonsei University, Wonju, Republic of Korea
| | - Geewon Lee
- Department of Radiology, Pusan National University Hospital, Busan, Republic of Korea
- Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Ji Won Lee
- Department of Radiology, Pusan National University Hospital, Busan, Republic of Korea
- Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Seung Baek Hong
- Department of Radiology, Pusan National University Hospital, Busan, Republic of Korea
- Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Young Ju Suh
- Department of Biomedical Sciences, School of Medicine, Inha University, Incheon, Republic of Korea
| | - Yeon Joo Jeong
- Department of Radiology, Pusan National University Hospital, Busan, Republic of Korea
- Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
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Effect of tube current on computed tomography radiomic features. Sci Rep 2018; 8:2354. [PMID: 29403060 PMCID: PMC5799381 DOI: 10.1038/s41598-018-20713-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/10/2018] [Indexed: 12/24/2022] Open
Abstract
Variability in the x-ray tube current used in computed tomography may affect quantitative features extracted from the images. To investigate these effects, we scanned the Credence Cartridge Radiomics phantom 12 times, varying the tube current from 25 to 300 mA∙s while keeping the other acquisition parameters constant. For each of the scans, we extracted 48 radiomic features from the categories of intensity histogram (n = 10), gray-level run length matrix (n = 11), gray-level co-occurrence matrix (n = 22), and neighborhood gray tone difference matrix (n = 5). To gauge the size of the tube current effects, we scaled the features by the coefficient of variation of the corresponding features extracted from images of non-small cell lung cancer tumors. Variations in the tube current had more effect on features extracted from homogeneous materials (acrylic, sycamore wood) than from materials with more tissue-like textures (cork, rubber particles). Thirty-eight of the 48 features extracted from acrylic were affected by current reductions compared with only 2 of the 48 features extracted from rubber particles. These results indicate that variable x-ray tube current is unlikely to have a large effect on radiomic features extracted from computed tomography images of textured objects such as tumors.
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The first joint ESGAR/ ESPR consensus statement on the technical performance of cross-sectional small bowel and colonic imaging. Eur Radiol 2016; 27:2570-2582. [PMID: 27757521 PMCID: PMC5408044 DOI: 10.1007/s00330-016-4615-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/11/2016] [Accepted: 09/15/2016] [Indexed: 12/28/2022]
Abstract
Objectives To develop guidelines describing a standardised approach to patient preparation and acquisition protocols for magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) of the small bowel and colon, with an emphasis on imaging inflammatory bowel disease. Methods An expert consensus committee of 13 members from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Paediatric Radiology (ESPR) undertook a six-stage modified Delphi process, including a detailed literature review, to create a series of consensus statements concerning patient preparation, imaging hardware and image acquisition protocols. Results One hundred and fifty-seven statements were scored for agreement by the panel of which 129 statements (82 %) achieved immediate consensus with a further 19 (12 %) achieving consensus after appropriate modification. Nine (6 %) statements were rejected as consensus could not be reached. Conclusions These expert consensus recommendations can be used to help guide cross-sectional radiological practice for imaging the small bowel and colon. Key points • Cross-sectional imaging is increasingly used to evaluate the bowel • Image quality is paramount to achieving high diagnostic accuracy • Guidelines concerning patient preparation and image acquisition protocols are provided
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Abstract
The synergy of functional and anatomic information in hybrid systems has undoubtedly enhanced the diagnostic potential of radionuclide imaging in recent years, contributing to the advancement of SPECT/CT in clinical practice. Since the introduction of commercial SPECT/CT in the late 1990 s, the field has seen rapid expansion and development toward multidetector CT subsystems, establishing the role of SPECT/CT as a routine imaging tool. It is, however, important to discuss possible challenges and technical limitations of such systems and how these influence imaging outcomes. In particular, the issues of patient motion and spatial misalignment of the SPECT and CT modalities, data corrections such as those for photon attenuation, and the choice of CT acquisition protocols in relation to radiation exposure are discussed in the article.
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Affiliation(s)
- Lefteris Livieratos
- Nuclear Medicine Department, Guy's & St Thomas' Hospitals, London, UK; Imaging Sciences and Biomedical Engineering, King's College London, London, UK.
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Padole A, Deedar Ali Khawaja R, Otrakji A, Zhang D, Liu B, Xu XG, Kalra MK. Comparison of Measured and Estimated CT Organ Doses for Modulated and Fixed Tube Current:: A Human Cadaver Study. Acad Radiol 2016; 23:634-42. [PMID: 26852248 DOI: 10.1016/j.acra.2015.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 11/27/2015] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to compare the directly measured and the estimated computed tomography (CT) organ doses obtained from commercial radiation dose-tracking (RDT) software for CT performed with modulated tube current or automatic exposure control (AEC) technique and fixed tube current (mAs). MATERIALS AND METHODS With the institutional review board (IRB) approval, the ionization chambers were surgically implanted in a human cadaver (88 years old, male, 68 kg) in six locations such as liver, stomach, colon, left kidney, small intestine, and urinary bladder. The cadaver was scanned with routine abdomen pelvis protocol on a 128-slice, dual-source multidetector computed tomography (MDCT) scanner using both AEC and fixed mAs. The effective and quality reference mAs of 100, 200, and 300 were used for AEC and fixed mAs, respectively. Scanning was repeated three times for each setting, and measured and estimated organ doses (from RDT software) were recorded (N = 3*3*2 = 18). RESULTS Mean CTDIvol for AEC and fixed mAs were 4, 8, 13 mGy and 7, 14, 21 mGy, respectively. The most estimated organ doses were significantly greater (P < 0.01) than the measured organ doses for both AEC and fixed mAs. At AEC, the mean estimated organ doses (for six organs) were 14.7 mGy compared to mean measured organ doses of 12.3 mGy. Similarly, at fixed mAs, the mean estimated organ doses (for six organs) were 24 mGy compared to measured organ doses of 22.3 mGy. The differences among the measured and estimated organ doses were higher for AEC technique compared to the fixed mAs for most organs (P < 0.01). CONCLUSIONS The most CT organ doses estimated from RDT software are greater compared to directly measured organ doses, particularly when AEC technique is used for CT scanning.
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How Much Is the Dose Varying between Follow-Up CT-Examinations Performed on the Same Scanner with the Same Imaging Protocol? PLoS One 2016; 11:e0152961. [PMID: 27050659 PMCID: PMC4822887 DOI: 10.1371/journal.pone.0152961] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 03/22/2016] [Indexed: 12/12/2022] Open
Abstract
Purpose To investigate the dose variation between follow-up CT examinations, when a patient is examined several times on the same scanner with the identical scan protocol which comprised automated exposure control. Material and Methods This retrospective study was approved by the local ethics committee. The volume computed tomography dose index (CTDIvol) and the dose-length-product (DLP) were recorded for 60 cancer patients (29 male, 31 female, mean age 60.1 years), who received 3 follow-up CT examinations each composed of a non-enhanced scan of the liver (LI-CT) and a contrast-enhanced scan of chest (CH-CT) and abdomen (AB-CT). Each examination was performed on the same scanner (Siemens Definition FLASH) equipped with automated exposure control (CARE Dose 4D and CARE KV) using the identical scan protocol. Results The median percentage difference in DLP between follow-up examinations was 9.6% for CH-CT, 10.3% for LI-CT, and 10.1% for AB-CT; the median percentage difference in CTDIvol 8.3% for CH-CT, 7.4% for LI-CT and 7.7% for AB-CT (p<0.0001 for all values). The maximum difference in DLP between follow-up examinations was 67.5% for CH-CT, 50.8% for LI-CT and 74.3% for AB-CT; the maximum difference in CTDIvol 62.9% for CH-CT, 47.2% for LI-CT, and 49% for AB-CT. Conclusion A significant variance in the radiation dose occurs between follow-up CT examinations when the same CT scanner and the identical imaging protocol are used in combination with automated exposure control.
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Lee AY, Elojeimy S, Kanal KM, Linnau KF, Gunn ML. The effect of trauma backboards on computed tomography radiation dose. Clin Radiol 2016; 71:499.e1-8. [PMID: 26932776 DOI: 10.1016/j.crad.2016.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 12/21/2015] [Accepted: 01/04/2016] [Indexed: 11/28/2022]
Abstract
AIM To assess the effect of trauma backboards on the radiation dose at computed tomography (CT) when using automatic tube current modulation (ATCM). MATERIALS AND METHODS An anthropomorphic phantom was scanned with two commercially available CT systems (GE LightSpeed16 Pro and Siemens Definition AS+) without and with backboards. Tube current-time product (mAs), and CTDIvol (mGy) were recorded for each examination. Thermoluminescent dosimeters were used to measure skin entrance dose in the pelvis and breast. Statistical significance was determined using a two-sample t-test. In addition, an institutional review board-approved retrospective image review was performed to quantify the frequency of backboard use during CT in the emergency department. RESULTS There was a statistically significant increase in maximum tube current-time product (p<0.05) and CTDIvol (p<0.05) with the presence of a backboard; tube current-time product increased up to 31% and CTDIvol increased up to 27%. There was a significant increase in skin entrance dose in the anterior and posterior pelvis (p<0.05) with the presence of a backboard; skin entrance dose increased up to 25% in the anterior pelvis. Skin entrance dose to the breast increased with a backboard, although this was not statistically significant. The frequency of backboard use during CT markedly decreased (from 77% to 3%) after instituting a multidisciplinary policy to promptly remove patients from backboards upon arrival to the emergency department after a primary clinical survey. CONCLUSIONS Using backboards during CT with ATCM can significantly increase the radiation dose. Although the decision to maintain patients on backboards is multifactorial, attempts should be made to minimise backboard use during CT when possible.
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Affiliation(s)
- A Y Lee
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 1600 Divisadero Street, San Francisco, CA 94115, USA
| | - S Elojeimy
- Department of Radiology, University of New Mexico, MSC 10-5530, Albuquerque, NM 87131, USA
| | - K M Kanal
- Department of Radiology, University of Washington, Box 359728, 325 9th Avenue, Seattle, WA 98104, USA
| | - K F Linnau
- Department of Radiology, University of Washington, Box 359728, 325 9th Avenue, Seattle, WA 98104, USA
| | - M L Gunn
- Department of Radiology, University of Washington, Box 359728, 325 9th Avenue, Seattle, WA 98104, USA.
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Impact of the scout view orientation on the radiation exposure and image quality in thoracic and abdominal CT. Eur Radiol 2016; 26:4072-4079. [PMID: 26943131 DOI: 10.1007/s00330-016-4285-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/24/2016] [Accepted: 02/16/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVES To assess the impact of the scout view orientation on radiation exposure and image quality in thoracoabdominal CT, when automated tube voltage selection (ATVS) and automated tube current modulation (ATCM) are used in combination with scan planning on a single scout view. METHODS Fifty patients underwent two thoracoabdominal CT examinations, one planned on an anteroposterior scout view, one planned on a lateral scout view. Both examinations included contrast-enhanced imaging of chest (CH) and abdomen (AB) and non-contrast-enhanced imaging of the liver (LI). For all examinations the same imaging protocol was used on the same dual-source CT scanner. The radiation exposure was recorded and objective as well as visual image quality was assessed for all examinations. RESULTS The median dose-length product was significantly lower in scans planned on a lateral scout view (CH: 179 vs. 218 mGy*cm, LI: 148 vs. 178 mGy*cm, AB: 324 vs. 370 mGy*cm, p < 0.0001). Objective image quality was marginal lower in scans planned on a lateral scout view, whereas the visual image quality was rated as equal. CONCLUSION At the tested radiation doses, the orientation of the scout view has a significant impact on the radiation exposure but no clinically relevant impact on the image quality. KEY POINTS • The scout view orientation has a significant impact on the radiation exposure. • The scout view orientation has no clinically relevant impact on image quality. • A lateral scout view should be preferred with regard to radiation exposure.
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Sookpeng S, Martin CJ, Gentle DJ. Influence of CT automatic tube current modulation on uncertainty in effective dose. RADIATION PROTECTION DOSIMETRY 2016; 168:46-54. [PMID: 25628455 DOI: 10.1093/rpd/ncu374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/29/2014] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) scanners are equipped with automatic tube current modulation (ATCM) systems that adjust the current to compensate for variations in patient attenuation. CT dosimetry variables are not defined for ATCM situations and, thus, only the averaged values are displayed and analysed. The patient effective dose (E), which is derived from a weighted sum of organ equivalent doses, will be modified by the ATCM. Values for E for chest-abdomen-pelvis CT scans have been calculated using the ImPACT spreadsheet for patients on five CT scanners. Values for E resulting from the z-axis modulation under ATCM have been compared with results assessed using the same effective mAs values with constant tube currents. Mean values for E under ATCM were within ±10 % of those for fixed tube currents for all scanners. Cumulative dose distributions under ATCM have been simulated for two patient scans using single-slice dose profiles measured in elliptical and cylindrical phantoms on one scanner. Contributions to the effective dose from organs in the upper thorax under ATCM are 30-35 % lower for superficial tissues (e.g. breast) and 15-20 % lower for deeper organs (e.g. lungs). The effect on doses to organs in the abdomen depends on body shape, and they can be 10-22 % higher for larger patients. Results indicate that scan dosimetry parameters, dose-length product and effective mAs averaged over the whole scan can provide an assessment in terms of E that is sufficiently accurate to quantify relative risk for routine patient exposures under ATCM.
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Affiliation(s)
- S Sookpeng
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - C J Martin
- Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
| | - D J Gentle
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK
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Nakamoto A, Kim T, Hori M, Onishi H, Tsuboyama T, Sakane M, Tatsumi M, Tomiyama N. Clinical evaluation of image quality and radiation dose reduction in upper abdominal computed tomography using model-based iterative reconstruction; comparison with filtered back projection and adaptive statistical iterative reconstruction. Eur J Radiol 2015; 84:1715-23. [DOI: 10.1016/j.ejrad.2015.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 10/23/2022]
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Sookpeng S, Martin CJ, Gentle DJ. Investigation of the influence of image reconstruction filter and scan parameters on operation of automatic tube current modulation systems for different CT scanners. RADIATION PROTECTION DOSIMETRY 2015; 163:521-530. [PMID: 25107439 DOI: 10.1093/rpd/ncu236] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Variation in the user selected CT scanning parameters under automatic tube current modulation (ATCM) between hospitals has a substantial influence on the radiation doses and image quality for patients. The aim of this study was to investigate the effect of changing image reconstruction filter and scan parameter settings on tube current, dose and image quality for various CT scanners operating under ATCM. The scan parameters varied were pitch factor, rotation time, collimator configuration, kVp, image thickness and image filter convolution (FC) used for reconstruction. The Toshiba scanner varies the tube current to achieve a set target noise. Changes in the FC setting and image thickness for the first reconstruction were the major factors affecting patient dose. A two-step change in FC from smoother to sharper filters doubles the dose, but is counterbalanced by an improvement in spatial resolution. In contrast, Philips and Siemens scanners maintained tube current values similar to those for a reference image and patient, and the tube current only varied slightly for changes in individual CT scan parameters. The selection of a sharp filter increased the image noise, while use of iDose iterative reconstruction reduced the noise. Since the principles used by CT manufacturers for ATCM vary, it is important that parameters which affect patient dose and image quality for each scanner are made clear to operator to aid in optimisation.
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Affiliation(s)
- Supawitoo Sookpeng
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
| | - Colin J Martin
- Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
| | - David J Gentle
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK
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Potential for Radiation Dose Savings in Abdominal and Chest CT Using Automatic Tube Voltage Selection in Combination With Automatic Tube Current Modulation. AJR Am J Roentgenol 2014; 203:292-9. [DOI: 10.2214/ajr.13.11628] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Sookpeng S, Martin CJ, Gentle DJ, Lopez-Gonzalez MR. Relationships between patient size, dose and image noise under automatic tube current modulation systems. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2014; 34:103-123. [PMID: 24334678 DOI: 10.1088/0952-4746/34/1/103] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles of ATCM operation are different in CT scanners from different manufacturers. Toshiba and GE scanners base the current modulation on a target noise setting, while Philips and Siemens scanners use reference image and reference mAs concepts respectively. Knowledge of the relationships between patient size, dose and image noise are important for CT patient dose optimisation. In this study, the CT patient doses were surveyed for 14 CT scanners from four different CT scanner manufacturers. The patient cross sectional area, the tube current modulation and the image noise from the CT images were analysed using in-house software. The Toshiba and GE scanner results showed that noise levels are relatively constant but tube currents are dependent on patient size. As a result of this there is a wide range in tube current values across different patient sizes, and doses for large patients are significantly higher in these scanners. In contrast, in the Philips and Siemens scanners, tube currents are less dependent on patient size, the range in tube current is narrower, and the doses for larger patients are not as high. Image noise is more dependent on the patient size.
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Affiliation(s)
- S Sookpeng
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK. Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
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Gervaise A, Osemont B, Louis M, Lecocq S, Teixeira P, Blum A. Standard dose versus low-dose abdominal and pelvic CT: Comparison between filtered back projection versus adaptive iterative dose reduction 3D. Diagn Interv Imaging 2014; 95:47-53. [DOI: 10.1016/j.diii.2013.05.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dose Reduction for Abdominal and Pelvic MDCT After Change to Graduated Weight-Based Protocol for Selecting Quality Reference Tube Current, Peak Kilovoltage, and Slice Collimation. AJR Am J Roentgenol 2013; 200:1298-303. [DOI: 10.2214/ajr.12.9387] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Stratis A, Kottou S, Molfetas M, Xirafi I, Delis H, Panayiotakis G. The effect of a combined tube current modulation system on dose delivered to patients undergoing thoracic and abdominal CT with a 128-slice scanner. RADIATION PROTECTION DOSIMETRY 2013; 153:206-211. [PMID: 23173217 DOI: 10.1093/rpd/ncs301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Combined tube current modulation techniques (such as Care Dose4D used in this study) during computed tomography (CT) procedures bring together the benefits of the angular and z-axis modulation techniques, measuring X-ray attenuation profile in the z-axis together with the data from the perpendicular x-y direction with a sophisticated algorithm. The purpose of this study was to investigate the radiation dose, in terms of computed tomography dose index (CTDI(vol)), delivered to patients during thoracic and abdominal CT using this technique and compare it with the corresponding CTDI(vol) of the fixed tube current CT technique. The results revealed a 5-32% dose reduction for chest CT and a dose reduction of 7.6-60% for the three-sequence abdominal CT scan of normal and overweight patients. In the case of obese patients a 15.4-18.7% dose increase for chest CT and a (-1.5) - (26.3)% dose increase for the three-stage abdominal examinations for females and males, respectively, was revealed.
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Affiliation(s)
- A Stratis
- Department of Medical Physics, School of Medicine, University of Patras, Patras 26500, Greece.
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Neroladaki A, Botsikas D, Boudabbous S, Becker CD, Montet X. Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations. Eur Radiol 2012; 23:360-6. [PMID: 22892722 DOI: 10.1007/s00330-012-2627-7] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. METHODS Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. RESULTS The radiation dose of ULD-CT was 0.16 ± 0.006 mSv compared with 11.2 ± 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. CONCLUSION Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray.
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Affiliation(s)
- Angeliki Neroladaki
- Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 4, Switzerland
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