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Vassileva J, Rehani M, Kostova-Lefterova D, Al-Naemi HM, Al Suwaidi JS, Arandjic D, Bashier EHO, Kodlulovich Renha S, El-Nachef L, Aguilar JG, Gershan V, Gershkevitsh E, Gruppetta E, Hustuc A, Jauhari A, Kharita MH, Khelassi-Toutaoui N, Khosravi HR, Khoury H, Kralik I, Mahere S, Mazuoliene J, Mora P, Muhogora W, Muthuvelu P, Nikodemova D, Novak L, Pallewatte A, Pekarovič D, Shaaban M, Shelly E, Stepanyan K, Thelsy N, Visrutaratna P, Zaman A. A study to establish international diagnostic reference levels for paediatric computed tomography. Radiat Prot Dosimetry 2015; 165:70-80. [PMID: 25836685 DOI: 10.1093/rpd/ncv116] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.
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Affiliation(s)
- J Vassileva
- International Atomic Energy Agency, Vienna, Austria
| | - M Rehani
- Harvard Medical School and Massachusetts General Hospital, Boston, USA
| | | | | | - J S Al Suwaidi
- Medical Education Department, Dubai Health Authority, Dubai, UAE
| | - D Arandjic
- Radiation Protection Department, Vinca Institute of Nuclear Sciences, Belgrade, Serbia
| | | | | | - L El-Nachef
- Lebanese Atomic Eneregy Commission, Beirut, Lebanon
| | - J G Aguilar
- National Institute for Nuclear Research, Carretera Mexico-Toluca, La Marquesa, Ocoyoacac, Mexico
| | - V Gershan
- Institute of Physics, Ss Cyril and Methodius University, Skopje, The former Yugoslav Republic of Macedonia
| | | | | | - A Hustuc
- National Centre of Public Health, Chisinau, Republic of Moldova
| | - A Jauhari
- Pusat Kajian Radiografi dan Imajing, Depok, Indonesia
| | | | - N Khelassi-Toutaoui
- Département de Physique Médicale, Centre de Recherche Nucléaire D'Alger, Algiers, Algiers
| | - H R Khosravi
- National Radiation Protection Department, Iranian Nuclear Regulatory Authority, Tehran, Iran
| | - H Khoury
- Universidade Federal de Pernambuco, Cidade Universitaria, Recife PE, Brazil
| | - I Kralik
- State Office for Radiological and Nuclear Safety, Zagreb, Croatia
| | - S Mahere
- Children Clinical University Hospital, Riga, Latvia
| | - J Mazuoliene
- Hospital of Lithuanian University of Health Science Kauno Klinikos, Kaunas, Lithuania
| | - P Mora
- Centro de Investigación en Ciencias Atómicas, Nucleares y Moleculares, Universidad de Costa Rica, San José, Costa Rica
| | - W Muhogora
- Tanzania Atomic Energy Commission, Arusha, Tanzania
| | - P Muthuvelu
- Ministry of Health Malaysia, Putrajaya Wilayah Persekutuan, Malaysia
| | - D Nikodemova
- Slovak Medical University, Limbova, Bratislava, Slovakia
| | - L Novak
- National Radiation Protection Institute, Prague, Czech Republic
| | - A Pallewatte
- Department of Radiology, The National Hospital of Sri Lanka, Colombo, Sri Lanka
| | - D Pekarovič
- Clinical Radiology Institute, University Medical Center, Ljubljana, Slovenia
| | - M Shaaban
- Al-Sabah Hospital, Kuwait City, Kuwait
| | - E Shelly
- Ministry of Health, Medical Technology and Infrastructure Administration, Jerusalem, Israel
| | - K Stepanyan
- Research Center of Radiation Medicine and Burns, Yerevan, Armenia
| | - N Thelsy
- Radiologist Ministry of Health, Yangon, Myanmar
| | - P Visrutaratna
- Faculty of Medicine, Department of Radiology, Chiang Mai University, Chiang Mai, Thailand
| | - A Zaman
- Institute of Nuclear Medicine and Oncology, PAEC, Lahore, Pakistan
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Moger CJ, Barrett R, Bleuet P, Bradley DA, Ellis RE, Green EM, Knapp KM, Muthuvelu P, Winlove CP. Regional variations of collagen orientation in normal and diseased articular cartilage and subchondral bone determined using small angle X-ray scattering (SAXS). Osteoarthritis Cartilage 2007; 15:682-7. [PMID: 17306566 DOI: 10.1016/j.joca.2006.12.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 12/23/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine regional differences in the orientation of collagen in the articular cartilage of the equine metacarpophalangeal joint as well as describing cartilage orientation in lesions using small angle X-ray scattering (SAXS). DESIGN SAXS diffraction patterns were taken at the European Synchrotron Radiation Facility (ESRF), with increasing depth into cartilage and bone cross sections. Results for healthy samples were taken at different regions along the joint which receive different loads and differences in collagen orientation were determined. Results were also taken from diseased samples and the collagen orientation changes from that of healthy samples observed. RESULTS Regions subject to low loads show a lower degree of orientation and regions exposed to the highest loads possess oriented collagen fibres especially in the radial layer. In early lesions the orientations of the collagen fibres are disrupted. Subchondral bone fibres are twisted in regions where the joint receives shear forces. Changes in fibre orientation are also observed in the calcified cartilage even in regions where the cartilage is intact. In more advanced lesions where there is loss of cartilage the fibres in the calcified layer are realigned tangential to the surface. CONCLUSIONS Regional variations in collagen arrangement show that the highly ordered layers of the articular cartilage are the most important elements in supporting high variable loads. In lesions changes occur in the deep tissue whilst the overlying cartilage appeared normal. We therefore suggest that the interface region is a key element in the early stages of the disease.
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Affiliation(s)
- C J Moger
- School of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, UK.
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Abstract
Anomalous Rayleigh scatter is examined for dilute concentrations of the biomedically relevant element iodine in aqueous media including measurements with monochromatic synchrotron radiation in the vicinity of the iodine K-edge. The measurements agree with anomalous scatter-factor corrections to the form-factor approximation which has been shown to have good agreement with higher precision S-matrix calculations for small angle scatter over a wide range of energies but has not been adequately tested at the edge. Monte Carlo modelling, including the modelling of polarized Compton and Rayleigh scattered x-rays, is used to determine the relative contributions of the scatter and fluorescent components at the detector as well as the modelling of self-absorption and relative dose in the determination of detection limits. A Rayleigh scatter minimum of 28 barns/sr was observed at an energy 10 +/- 5 eV below the K-edge of iodine at a position predicted from an evaluation of the dispersion integral that includes bound-bound resonance contributions. Minimum detectable concentrations for observation of the anomalous Rayleigh scatter feature at an exposure of 10 mSv, predicted for iodine and iron, are 1 mg ml(-1) and 10 mg ml(-1), respectively. Upper limits to detection of the feature imposed by degradation of the signal by self-absorption are 0.021 g cm(-2) and 0.0029 g cm(-2) radiation lengths, respectively.
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Affiliation(s)
- Richard P Hugtenburg
- Imaging and Medical Physics Group, Queen Elizabeth Hospital, University Hospital NHS Trust, Birmingham, UK.
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