Browsing by Author "England, Andrew"
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- Are antimony-bismuth aprons as efficient as lead rubber aprons in providing shielding against scattered radiation?Publication . Johansen, Safora; Hauge, Ingrid; Hogg, Peter; England, Andrew; Lança, Luís; Gunn, Catherine; Sanderud, AudunAim: The aim of this study is to compare the absorption ability of two lead-free aprons with a lead apron. Method: The absorption ability of three aprons was measured and compared; Opaque Fusion 0.35 mm (OpaqFu) bilayer apron containing bismuth and antimony, No Lead 0.35 mm (NoLead) one-layer apron containing antimony, and a lead apron. The measurements were repeated with and without each of the aprons present in both primary and scattered beams. The selected tube voltages were between 60 and 113 kVp with constant mAs, a fixed field size, and fixed source-to-object distance. Results: No significant difference in absorption ability of the two lead-free aprons compared with that of the lead apron was observed when the dose was measured in the primary beam. When measurements were performed in the scatter radiation field, the absorption ability of the OpaqFu apron was 1.3 times higher than that of NoLead apron and nearly equal to the absorption ability of the lead apron. An increase in the difference between the OpaqFu and NoLead aprons was observed for the tube energies higher than 100 kVp in favor of OpaqFu apron. Conclusion: It is safe to use the lead-free aprons that were tested in this study in a clinical environment for the tube energy range of 60 kVp–113 kVp.
- A balance between image quality and effective dose in orbital X-ray screening for ferromagnetic IOFBs: a pilot studyPublication . Hart, Gabrielle; Jessop, Sarah; Santiago, Ana Rita; Samara, Abbas; Markali, Benedicte; Cottier, Yann; Guerreiro, Joana; Andersen, Erik Normann; Momoniat, H.; Jorge, José; England, AndrewPurpose: To investigate whether standard X-ray acquisition factors for orbital radiographs are suitable for the detection of ferromagnetic intra-ocular foreign bodies in patients undergoing MRI. Method: 35 observers, at varied levels of education in radiography, attending a European Dose Optimisation EURASMUS Summer School were asked to score 24 images of varying acquisition factors against a clinical standard (reference image) using two alternative forced choice. The observers were provided with 12 questions and a 5 point Likert scale. Statistical tests were used to validate the scale, and scale reliability was also measured. The images which scored equal to, or better than, the reference image (36) were ranked alongside their corresponding effective dose (E), the image with the lowest dose equal to or better than the reference is considered the new optimum acquisition factors. Results: Four images emerged as equal to, or better than, the reference in terms of image quality. The images were then ranked in order of E. Only one image that scored the same as the reference had a lower dose. The reference image had a mean E of 3.31μSv, the image that scored the same had an E of 1.8μSv. Conclusion: Against the current clinical standard exposure factors of 70kVp, 20mAs and the use of an anti- scatter grid, one image proved to have a lower E whilst maintaining the same level of image quality and lesion visibility. It is suggested that the new exposure factors should be 60kVp, 20mAs and still include the use of an anti-scatter grid.
- Development and validation of a psychometric scale for assessing PA chest image qualityPublication . Mraity, Hussein; Akhtar, Ifrah; Aslam, Aisha; England, Andrew; de Lange, René; Momoniat, Hafsa; Nicoulaz, Solange; Ribeiro, Ana Isabel; Hogg, PeterPurpose - To develop and validate a psychometric scale for assessing image quality for chest radiographs.
- A novel method for comparing radiation dose and image quality, between and within different x-ray units in a series of hospitalsPublication . Al-Murshedi, Sadeq; Hogg, Peter; Lança, Luís; England, AndrewObjectives - To develop a novel method for comparing radiation dose and image quality (IQ) to evaluate adult chest x-ray (CXR) imaging among several hospitals. Methods - CDRAD 2.0 phantom was used to acquire images in eight hospitals (17 digital x-ray units) using local adult CXR protocols. IQ was represented by image quality figure inverse (IQFinv), measured using CDRAD analyser software. Signal to noise ratio, contrast to noise ratio and conspicuity index were calculated as additional measures of IQ. Incident air kerma (IAK) was measured using a solid-state dosimeter for each acquisition. Figure of merit (FOM) was calculated to provide a single estimation of IQ and radiation dose. Results - IQ, radiation dose and FOM varied considerably between hospitals and x-ray units. For IQFinv, the mean (range) between and within the hospitals were 1.42 (0.83-2.18) and 1.87 (1.52-2.18), respectively. For IAK, the mean (range) between and within the hospitals were 93.56 (17.26-239.15) μGy and 180.85 (122.58-239.15) μGy, respectively. For FOM, the mean (range) between and within hospitals were 0.05 (0.01-0.14) and 0.03 (0.02-0.05), respectively. Concluysions - The suggested method for comparing IQ and dose using FOM concept along with the new proposed FOM, is a valid, reliable and effective approach for monitoring and comparing IQ and dose between and within hospitals. It is also can be beneficial for the optimisation of x-ray units in clinical practice. Further optimisation for the hospitals/x-ray units with low FOM are required to minimise radiation dose without degrading IQ.
- X Radiation dose implications in screening patients with ferromagnetic IOFBs prior to MRI: a literary reviewPublication . Jessop, Sarah; Hart, Gabrielle; Santiago, Ana Rita; Samara, Abbas; Markali, Benedicte; Cottier, Yann; Guerreiro, Joana; Andersen, Erik Normann; Momoniat, H.; Jorge, José; England, AndrewPatients scheduled for a magnetic resonance imaging (MRI) scan sometimes require screening for ferromagnetic Intra Orbital Foreign Bodies (IOFBs). To assess this, they are required to fill out a screening protocol questionnaire before their scan. If it is established that a patient is at high risk, radiographic imaging is necessary. This review examines literature to evaluate which imaging modality should be used to screen for IOFBs, considering that the eye is highly sensitive to ionising radiation and any dose should be minimised. Method: Several websites and books were searched for information, these were as follows: PubMed, Science Direct, Web of Knowledge and Google Scholar. The terms searched related to IOFB, Ionising radiation, Magnetic Resonance Imaging Safety, Image Quality, Effective Dose, Orbits and X-ray. Thirty five articles were found, several were rejected due to age or irrelevance; twenty eight were eventually accepted. Results: There are several imaging techniques that can be used. Some articles investigated the use of ultrasound for investigation of ferromagnetic IOFBs of the eye and others discussed using Computed Tomography (CT) and X-ray. Some gaps in the literature were identified, mainly that there are no articles which discuss the lowest effective dose while having adequate image quality for orbital imaging. Conclusion: X-ray is the best method to identify IOFBs. The only problem is that there is no research which highlights exposure factors that maintain sufficient image quality for viewing IOFBs and keep the effective dose to the eye As Low As Reasonably Achievable (ALARA).