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Viry A, Vitzthum V, Monnin P, Bize J, Rotzinger D, Racine D. Optimization of CT pulmonary angiography for pulmonary embolism using task-based image quality assessment and diagnostic reference levels: A multicentric study. Phys Med 2024; 121:103365. [PMID: 38663347 DOI: 10.1016/j.ejmp.2024.103365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/12/2024] [Accepted: 04/19/2024] [Indexed: 05/12/2024] Open
Abstract
PURPOSE To establish size-specific diagnostic reference levels (DRLs) for pulmonary embolism (PE) based on patient CT examinations performed on 74 CT devices. To assess task-based image quality (IQ) for each device and to investigate the variability of dose and IQ across different CTs. To propose a dose/IQ optimization. METHODS 1051 CT pulmonary angiography dose data were collected. DRLs were calculated as the 75th percentile of CT dose index (CTDI) for two patient categories based on the thoracic perimeters. IQ was assessed with two thoracic phantom sizes using local acquisition parameters and three other dose levels. The area under the ROC curve (AUC) of a 2 mm low perfused vessel was assessed with a non-prewhitening with eye-filter model observer. The optimal IQ-dose point was mathematically assessed from the relationship between IQ and dose. RESULTS The DRLs of CTDIvol were 6.4 mGy and 10 mGy for the two patient categories. 75th percentiles of phantom CTDIvol were 6.3 mGy and 10 mGy for the two phantom sizes with inter-quartile AUC values of 0.047 and 0.066, respectively. After the optimization, 75th percentiles of phantom CTDIvol decreased to 5.9 mGy and 7.55 mGy and the interquartile AUC values were reduced to 0.025 and 0.057 for the two phantom sizes. CONCLUSION DRLs for PE were proposed as a function of patient thoracic perimeters. This study highlights the variability in terms of dose and IQ. An optimization process can be started individually and lead to a harmonization of practice throughout multiple CT sites.
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Affiliation(s)
- Anaïs Viry
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland.
| | - Veronika Vitzthum
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - Pascal Monnin
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - Julie Bize
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - David Rotzinger
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, 1011, Lausanne, Switzerland
| | - Damien Racine
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
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Inoue Y, Itoh H, Nagahara K, Hata H, Mitsui K. Relationships of Radiation Dose Indices with Body Size Indices in Adult Body Computed Tomography. Tomography 2023; 9:1381-1392. [PMID: 37489478 PMCID: PMC10366833 DOI: 10.3390/tomography9040110] [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: 06/11/2023] [Revised: 07/08/2023] [Accepted: 07/12/2023] [Indexed: 07/26/2023] Open
Abstract
We investigated the relationships between radiation dose indices and body size indices in adult body computed tomography (CT). A total of 3200 CT scans of the thoracic, abdominal, abdominopelvic, or thoraco-abdominopelvic regions performed using one of four CT scanners were analyzed. Volume CT dose index (CTDIvol) and dose length product (DLP) were compared with various body size indices derived from CT images (water-equivalent diameter, WED; effective diameter, ED) and physical measurements (weight, weight/height, body mass index, and body surface area). CTDIvol showed excellent positive linear correlations with WED and ED. CTDIvol also showed high linear correlations with physical measurement-based indices, whereas the correlation coefficients were lower than for WED and ED. Among the physical measurement-based indices, weight/height showed the strongest correlations, followed by weight. Compared to CTDIvol, the correlation coefficients with DLP tended to be lower for WED, ED, and weight/height and higher for weight. The standard CTDIvol values at 60 kg and dose increase ratios with increasing weight, estimated using the regression equations, differed among scanners. Radiation dose indices closely correlated with body size indices such as WED, ED, weight/height, and weight. The relationships between dose and body size differed among scanners, indicating the significance of dose management considering body size.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Japan
| | - Hiroyasu Itoh
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0375, Japan
| | - Kazunori Nagahara
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0375, Japan
| | - Hirofumi Hata
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0375, Japan
| | - Kohei Mitsui
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Japan
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De Monte F, Sapignoli S, Laura Cortinovis A, Di Maggio A, Nardin M, Pizzirani E, Scagliori E, Volpe A, Paiusco M, Roggio A. Effectiveness of body size stratification for patient exposure optimization in Computed Tomography. Eur J Radiol 2023; 163:110804. [PMID: 37043885 DOI: 10.1016/j.ejrad.2023.110804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/23/2023] [Accepted: 03/26/2023] [Indexed: 03/31/2023]
Abstract
PURPOSE To establish size-dependent DRL and to estimate the effectiveness of the size-dependent DRLs over size-independent DRLs for a CT exposure optimization process. METHODS The study included 16,933 adult CT body examinations of the most common CT protocols. Acquisitions were included following an image quality assessment. Patients were grouped into five different classes by means of the water equivalent diameter (Dw): 21 ≤ Dw < 25, 25 ≤ Dw < 29, 29 ≤ Dw < 33,33 ≤ Dw < 37 (in cm). CTDIvol, DLP, DLPtot. and SSDE median values were provided both for the sample as a whole (size-independent approach) and for each Dw class (size-dependent approach). The performance of the two approaches in classifying sub-optimal examinations was evaluated through the confusion matrix and Matthews Correlation Coefficient (MCC) metric. The 75th percentile of the CTDIvol distribution was arbitrarily chosen as a threshold level above which the acquisitions are considered sub-optimal. RESULTS CTDIvol, DLP, DLPtot and SSDE typical values (median values) are statistically different across Dw groups. The confusion matrix analysis suggests that size-independent DRL could not mark potential suboptimal protocols for small and large patients. The agreement between the size-dependent and size-independent methods is strong only for the most populous classes (MCC > 0.7). For small and large patients size-independent approach fails to identify as sub-optimal around 20 % of the acquisition (MCC≪0.2). CONCLUSIONS It was proven by means of the confusion matrix and MCC metric that stratifying DRLs by patient size, size-dependent DRL can be a powerful strategy in order to improve the dose optimization process shown that a size-independent DRL fails to identify sub-optimal examinations for small and large patients.
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Moghadam N, Lecomte R, Mercure S, Rehani MM, Nassiri MA. Simplified size adjusted dose reference levels for adult CT examinations: A regional study. Eur J Radiol 2021; 142:109861. [PMID: 34280596 DOI: 10.1016/j.ejrad.2021.109861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/30/2021] [Accepted: 07/06/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE To investigate retrospective classification of adult patients into small, average, and large based on effective diameter (EDia) from localizer image of computed tomography (CT) scans and to develop regional diagnostic reference levels (DRLs) and achievable doses (AD). METHOD The patients falling within the mean ± standard deviation (SD) of EDia were classified as average; those below this range as small and above as large. The CTDIvol,dose-length-product (DLP) and size-specific dose estimates (SSDE) of all adult patients undergoing CT examinations in 8 CT facilities for 11 months (Dec. 2019 - Oct. 2020) were evaluated. The 75th and 50th percentile values were compared with national and international values. RESULTS Of the total of 69,434 CT examinations, nearly 80% fell within average size. The 75th percentile values of CTDIvol and DLP for small patients for abdomen-pelvic exams were nearly half of average sized patients. Similarly, the 75th percentile values for large patients were nearly double. Similar findings were not found for chest exams. Analysis of image quality and dose factors such as noise, mean axial length, slice thickness, mean number of sequences, use of iterative reconstruction and tube current modulation (TCM) resulted in identification of opportunities for improvement and optimization of different CT facilities. CONCLUSIONS DRLs for adult patients were found to vary widely with patient size and thus establishing DRLs only for standard sized patient is not adequate. Simplified and intuitive methods for size classification was shown to provide meaningful information for optimization for patients outside the standard size adult.
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Affiliation(s)
- Narjes Moghadam
- Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CRCHUS), Sherbrooke, Québec, Canada; Centre intégré universitaire de santé et de services sociaux de l'Estrie - Centre hospitalier universitaire de Sherbrooke (CIUSSS de l'Estrie - CHUS), Sherbrooke, Québec, Canada.
| | - Roger Lecomte
- Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CRCHUS), Sherbrooke, Québec, Canada; Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada
| | - Stéphane Mercure
- Centre intégré universitaire de santé et de services sociaux de l'Estrie - Centre hospitalier universitaire de Sherbrooke (CIUSSS de l'Estrie - CHUS), Sherbrooke, Québec, Canada
| | - Madan M Rehani
- Radiology Department, Massachusetts General Hospital, Boston, MA, USA
| | - Moulay Ali Nassiri
- Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CRCHUS), Sherbrooke, Québec, Canada; Centre intégré universitaire de santé et de services sociaux de l'Estrie - Centre hospitalier universitaire de Sherbrooke (CIUSSS de l'Estrie - CHUS), Sherbrooke, Québec, Canada; Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada
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Jeukens CRLPN, Boere H, Wagemans BAJM, Nelemans PJ, Nijssen EC, Smith-Bindman R, Wildberger JE, Sailer AM. Probability of receiving a high cumulative radiation dose and primary clinical indication of CT examinations: a 5-year observational cohort study. BMJ Open 2021; 11:e041883. [PMID: 33455933 PMCID: PMC7813417 DOI: 10.1136/bmjopen-2020-041883] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE High radiation exposure is a concern because of the association with cancer. The objective was to determine the probability of receiving a high radiation dose from CT (from one or more examinations within a 5-year period) and to assess the clinical context by evaluating clinical indications in the high-dose patient group. DESIGN Observational cohort study. Effective radiation dose received from one or more CT examinations within a predefined 5-year calendar period was assessed for each patient. SETTING Hospital setting. PARTICIPANTS All patients undergoing a diagnostic CT examination between July 2013 and July 2018 at the Maastricht University Medical Center. PRIMARY AND SECONDARY OUTCOME MEASURES The primary outcome was the probability of receiving a high effective dose, defined as ≥100 mSv, from one or more CT examinations within 5 years as derived from a time-to-event analysis. Secondary outcomes were the clinical indication for the initial scan of patients receiving a high effective dose. RESULTS 100 672 CT examinations were performed among 49 978 patients including 482 (1%) who received a high radiation dose. The estimated probability of a high effective dose from a single examination is low (0.002% (95% CI 0.00% to 0.01%)). The 4.5-year probability of receiving a high cumulative effective dose was 1.9% (95% CI 1.6% to 2.2%) for women and 1.5% (95% CI 1.3% to 1.7%) for men. The probability was highest in age categories between 51 and 74 years. A total of 2711 (5.5%) of patients underwent more than six CT examinations, and the probability of receiving a high effective dose was 16%. Among patients who received a high effective dose, most indications (80%) were oncology related. CONCLUSIONS The probability of receiving a high radiation dose from CT examinations is small but not negligible. In the majority (80%) of high effective dose receiving patients, the indication for the initial CT scan was oncology related.
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Affiliation(s)
- Cécile R L P N Jeukens
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Hub Boere
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Bart A J M Wagemans
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Patty J Nelemans
- Department of Epidemiology, Maastricht University, Maastricht, The Netherlands
| | - Estelle C Nijssen
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
- CARIM, School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Rebecca Smith-Bindman
- Department of Radiology and Biomedical Imaging Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA
- Department of Obstetrics Gynecology and Reproductive Sciences, Philip R Lee Institute for Health Policy Studies, University of California, San Francisco, San Francisco, USA
| | - Joachim E Wildberger
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Anna M Sailer
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
- Department of Radiology, Stanford University School of Medicine, Stanford, California, USA
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Klosterkemper Y, Thomas C, Bethge OT, Appel E, Aissa J, Boeven J, Antoch G, Boos J. Implementation of Institutional Size-Specific Diagnostic Reference Levels for CT Angiography. Acad Radiol 2019; 26:1661-1667. [PMID: 30803896 DOI: 10.1016/j.acra.2019.01.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022]
Abstract
RATIONALE AND OBJECTIVES To generate institutional size-specific diagnostic reference levels (DRLs) for computed tomography angiography (CTA) examinations and assess the potential for dose optimization compared to size-independent DRLs. MATERIALS AND METHODS CTA examinations of the aorta, the pulmonary arteries and of the pelvis/lower extremity performed between January 2016 and January 2017 were included in our retrospective study. Water equivalent diameter (Dw) was automatically calculated for each patient. The relationship between Dw and computed tomography dose index (CTDIvol) was analyzed and the 75th percentile was chosen as the upper limit for institutional DRLs. Size-specific institutional DRLs were compared to national size-independent DRLs from Germany and the UK. RESULTS A total of 1344 examinations were included in our study (n = 733 aortic CTA, n = 406 pulmonary CTA, n = 205 pelvic/lower extremity CTA). Mean Dw was 26 ± 9 cm and mean CTDIvol was 7.0 ± 4.6 mGy. For all CTA protocols, there was a linear progression of CTDIvol with increasing Dw with an R² = 0.95 in aortic CTA, R² = 0.94 in pulmonary CTA and R² = 0.93 in pelvic/lower extremity CTA. Median CTDIvol increased by 0.57 mGy per additional cm Dw in aortic CTA, by 1.1 mGy in pulmonary CTA and by 0.31 mGy in pelvic/lower extremity CTA. Institutional DRLs were lower than national DRLs for average size patients (aortic CTA: Dw 28.2 cm, CTDIvol 7.6 mGy; pulmonary CTA, Dw 27.9 cm, CTDIvol 11.8 mGy; pelvic/lower extremity CTA, Dw 20.0 cm, CTDIvol 6.4 mGy). More dose outliers in small patients were detected with size-specific DRLs compared to national size-independent DRLs (56.4% vs 16.2%). CONCLUSION We implemented institutional size-specific DRLs for CTA examinations which enabled a more precise analysis compared to national sizeindependent DRLs.
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Brat H, Zanca F, Montandon S, Racine D, Rizk B, Meicher E, Fournier D. Local clinical diagnostic reference levels for chest and abdomen CT examinations in adults as a function of body mass index and clinical indication: a prospective multicenter study. Eur Radiol 2019; 29:6794-6804. [PMID: 31144074 DOI: 10.1007/s00330-019-06257-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/16/2019] [Accepted: 04/26/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To compare institutional dose levels based on clinical indication and BMI class to anatomy-based national DRLs (NDRLs) in chest and abdomen CT examinations and to assess local clinical diagnostic reference levels (LCDRLs). METHODS From February 2017 to June 2018, after protocol optimization according to clinical indication and body mass index (BMI) class (< 25; ≥ 25), 5310 abdomen and 1058 chest CT series were collected from 5 CT scanners in a Swiss multicenter group. Clinical indication-based institutional dose levels were compared to the Swiss anatomy-based NDRLs. Statistical significance was assessed (p < 0.05). LCDRLs were calculated as the third quartile of the median dose values for each CT scanner. RESULTS For chest examinations, dose metrics based on clinical indication were always below P75 NDRL for CTDIvol (range 3.9-6.4 vs. 7.0 mGy) and DLP (164.0-211.2 vs. 250 mGycm) in all BMI classes except for DLP in BMI ≥ 25 (248.8-255.4 vs. 250.0 mGycm). For abdomen examinations, they were significantly lower or not different than P50 NDRLs for all BMI classes (3.8-9.0 vs. 10.0 mGy and 192.9-446.8 vs. 470mGycm). The estimated LCDRLs show a drop in CTDIvol (21% for chest and 32% for abdomen, on average) with respect to current DRLs. When considering BMI stratification, the largest LCDRL difference within the same clinical indication is for renal tumor (4.6 mGy for BMI < 25 vs. 10.0 mGy for BMI ≥ 25; - 117%). CONCLUSION The results suggest the necessity of estimating clinical indication-based DRLs, especially for abdomen examinations. Stratifying per BMI class allows further optimization of the CT doses. KEY POINTS • Our data show that clinical indication-based DRLs might be more appropriate than anatomy-based DRLs and might help in reducing large variations in dose levels for the same type of examinations. • Stratifying the data per patient-size subgroups (non-overweight, overweight) allows a better optimization of CT doses and therefore the possibility to set LCDRLs based on BMI class. • Institutions who are fostering continuous dose optimization and LDRLs should consider defining protocols based on clinical indication and BMI group, to achieve ALARA.
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Affiliation(s)
- Hugues Brat
- Institut de Radiologie de Sion, Groupe 3R, Sion, Switzerland.
| | - Federica Zanca
- GE Healthcare, Buc, France.,Palindromo Consulting, Leuven, Belgium
| | | | - Damien Racine
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Benoit Rizk
- Institut de Radiologie de Sion, Groupe 3R, Sion, Switzerland
| | - Eric Meicher
- Institut de Radiologie de Sion, Groupe 3R, Sion, Switzerland
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Potential of a machine-learning model for dose optimization in CT quality assurance. Eur Radiol 2019; 29:3705-3713. [DOI: 10.1007/s00330-019-6013-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/17/2019] [Indexed: 11/25/2022]
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