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Computed tomography and patient risk:Facts,perceptions and uncertainties

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World journal of Radiology 2016年第12期8卷 902-915页

作者： Stephen P Power Fiachra Moloney Maria Twomey Karl james owen j o'connor Michael M Maher Department of Radiology Cork University Hospital

Since its introduction in the 1970s, computed tomography(CT) has revolutionized diagnostic decision-making. one of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.

关键词： Computed tomography Radiation dose Iterative reconstruction Neoplasia Carcinogenesis

Effects of oral contrast on dose in abdominopelvic computed tomography with pure iterative reconstruction

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World journal of Radiology 2016年第9期8卷 809-815页

作者： Kevin P Murphy Liam j Healy Lee Crush Maria Twomey Fiachra Moloney Sylvia Sexton owen j o'connor Michael M Maher Department of Radiology Cork University Hospital

AIM To assess the effect of neutral(NC) and positive(PC) oral contrast use on patient dose in low-dose abdominal computed tomography(CT).METHoDS Low-dose clinically indicated CTs were performed on 79 Crohn's patients(35 = PC, 1 L 2% gastrografin; 44 = NC, 1.5 L polyethylene glycol). Scanner settings for both acquisitions were identical apart from 25 s difference in intravenous contrast timing. Body mass index(BMI), scan-ranges, dose-length product and size-specific dose estimated were recorded. Data was reconstructed with pure model-based iterative reconstruction. Image quality was objectively and subjectively analysed. Data analysis was performed with Statistical Package for Social *** Higher doses were seen in neutral contrast CTs(107.60 ± 78.7 m ***, 2.47 ± 1.21 m Gy vs 85.65 ± 58.2 m ***, 2.18 ± 0.96 m Gy). The differencehad both NC and PC investigations. Image-quality assessment yielded 6952 datapoints. NC image quality was significantly superior(P objective noise, objective signal to noise ratio, subjective spatial resolution, subjective contrast resolution, diagnostic acceptability) at all levels. NC bowel distension was significantly(P of polyethylene glycol as a neutral oC agent leads to higher radiation doses than standard positive contrast studies, in low dose abdominal CT imaging. This is possibly related to the osmotic effect of the agent resulting in larger intraluminal fluid volumes and resultant increased overall beam attenuation.

关键词： Radiation dose Low dose computed tomography Abdominal imaging oral contrast Computed tomography

C-reactive protein and radiographic findings of lower respiratory tract infection in infants

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World journal of Radiology 2017年第4期9卷 206-211页

作者： Maria Twomey Hannah Fleming Fiachra Moloney Kevin P Murphy Lee Crush Siobhan B o’Neill oisin Flanagan Karl james Conor Bogue owen j o’connor Michael M Maher Department of Radiology Cork University HospitalWiltonT12 DC4A CorkIreland

AIM To evaluate the association between C-reactive protein(CRP) and radiological evidence of lower respiratory tract infection(LRTI) in *** All patients aged less than 4 years who presented with suspected lower respiratory tract infection,who received a peri-presentation chest radiograph and CRP blood measurement over an 18-mo period were included in the ***,gender,source of referral,CRP,white cell count,neutrophil count along with the patients' symptoms and radiologist's report were *** Three hundred and eleven patients met the *** chest radiographs were more common in patients with elevated CRP levels(P ologic signs of LRTI were identified in 73.7% of chest radiographs when a patient had a CRP level between 50-99 mg/*** levels were a better predictor of positive chest radiograph findings for those aged greater than I year compared to those 1 year or *** CRP may be used in patients with suspected LRTI diagnosis to select those who are likely to have positive findings on chest radiograph,thus reducing unnecessary chest radiographs.

关键词： Chest radiograph C-reactive protein Chest infection Respiratory infection Pediatric

Computed tomography dose optimisation in cystic fibrosis:A review

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World journal of Radiology 2016年第4期8卷 331-341页

作者： Helena Ferris Maria Twomey Fiachra Moloney Siobhan B o'Neill Kevin Murphy owen j o'connor Michael Maher Department of Radiology Cork University Hospital

Cystic fibrosis(CF)is the most common autosomal recessive disease of the Caucasian population worldwide,with respiratory disease remaining the most relevant source of morbidity and *** tomography(CT)is frequently used for monitoring disease complications and *** the last fifteen years there has been a six-fold increase in the use of CT,which has lead to a growing concern in relation to cumulative radiation *** challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality,but fulfil the requirements of a diagnostic quality ***-optimisation,particularly in CT,is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 m Sv,a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic *** review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

关键词： Cystic fibrosis Dose optimization Computed tomography Dose Ionising radiation Kalydeco

Cumulative radiation exposure from diagnostic imaging in intensive care unit patients

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World journal of Radiology 2016年第4期8卷 419-427页

作者： Fiachra Moloney Daniel Fama Maria Twomey Ruth o'Leary Conor Houlihane Kevin P Murphy Siobhan B o'Neill owen j o'connor Dorothy Breen Michael M Maher Department of Radiology Cork University Hospital Department of Anesthesia Cork University Hospital

AIM:To quantify cumulative effective dose of intensive care unit(ICU)patients attributable to diagnostic ***:This was a prospective,interdisciplinary study conducted in the ICU of a large tertiary referral and level 1 trauma *** and clinical data including age,gender,date of ICU admission,primary reason for ICU admission,APACHE Ⅱ score,length of stay,number of days intubated,date of death or discharge,and re-admission data was collected on all patients admitted over a 1-year *** overall radiation exposure was quantified by the cumulative effective radiation dose(CED)in millisieverts(mS v)and calculated using reference effective doses published by the United Kingdom National Radiation Protection *** patients were selected for ***:A total of 2737 studies were performedin 421 *** total CED was 1704 m Sv with a median CED of 1.5 mS v(IQR 0.04-6.6 mS v).Total CED in pediatric patients was 74.6 mS v with a median CED of 0.07 mS v(IQR 0.01-4.7 mS v).Chest radiography was the most commonly performed examination accounting for 83% of all studies but only 2.7% of total *** tomography(CT)accounted for 16% of all studies performed and contributed 97% of total *** patients received a statistically significant higher dose [median CED 7.7 mS v(IQR 3.5-13.8 mS v)] than medical [median CED 1.4 m Sv(IQR 0.05-5.4 m Sv)] and surgical [median CED 1.6 mS v(IQR 0.04-7.5 mS v)] *** of stay in ICU [oR = 1.12(95%CI:1.079-1.157)] was identified as an independent predictor of receiving a CED greater than 15 mS ***:Trauma patients and patients with extended ICU admission times are at increased risk of higher *** should be minimized where feasible,especially in young patients.

关键词： Cumulative effective dose Pediatric patients Computed tomography Radiation dose Intensive care unit

MDGA2 Constrains Glutamatergic Inputs Selectively onto CA1 Pyramidal Neurons to optimize Neural Circuits for Plasticity,Memory,and Social Behavior

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Neuroscience Bulletin 2024年第7期40卷 887-904页

作者： Xuehui Wang Donghui Lin jie jiang Yuhua Liu Xinyan Dong jianchen Fan Lifen Gong Weida Shen Linghui Zeng Tonghui Xu Kewen jiang Steven A.connor Yicheng Xie School of Life Sciences Nanchang UniversityNanchang330031China Department of Neurology Children's HospitalZhejiang University School of MedicineNational Clinical Research Center for Child HealthHangzhou 310052China Department of Biology York University4700 Keele StreetTorontoON M3J 1P3Canada Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province School of MedicineHangzhou City UniversityHangzhou 310015China

Synapse organizers are essential for the development,transmission,and plasticity of *** as rare synapse suppressors,the MAM domain containing glycosylphosphatidylinositol anchor(MDGA)proteins contributes to synapse organization by inhibiting the formation of the synaptogenic neuroligin-neurexin complex.A previous analysis of MDGA2 mice lacking a single copy of Mdga2 revealed upregulated glutamatergic synapses and behaviors consistent with ***,MDGA2 is expressed in diverse cell types and is localized to both excitatory and inhibitory *** the network versus cell-specific effects of MDGA2 loss-of-function requires a cell-type and brain region-selective *** address this,we generated mice harboring a conditional knockout of Mdga2 restricted to CA1 pyramidal *** we report that MDGA2 suppresses the density and function of excitatory synapses selectively on pyramidal neurons in the mature *** deletion of Mdga2 in CA1 pyramidal neurons of adult mice upregulated miniature and spontaneous excitatory postsynaptic potentials,vesicular glutamate transporter 1 intensity,and neuronal *** effects were limited to glutamatergic synapses as no changes were detected in miniature and spontaneous inhibitory postsynaptic potential properties or vesicular GABA transporter ***,evoked basal synaptic transmission and AMPAR receptor currents were enhanced at glutamatergic *** a behavioral level,memory appeared to be compromised in Mdga2 cKo mice as both novel object recognition and contextual fear conditioning performance were impaired,consistent with deficits in long-term potentiation in the CA3-CA1 *** affiliation,a behavioral analog of social deficits in autism,was similarly *** results demonstrate that MDGA2 confines the properties of excitatory synapses to CA1 neurons in mature hippocampal circuits,thereby optimizing this network for plasticity,c

关键词： MDGA2 CA1 pyramidal neurons Glutamatergic inputs Synaptic plasticity Memory Social behaviors Autism Synapse organizers

Modelling internal air systems ingas turbine engines

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航空动力学报 2007年第4期22卷 505-520页

作者： j Michael owen Department of Mechanical Engineering University of Bath

Rotating-disc systems can be used to model,experimentally and computationally,the flow and heat transfer that occur inside the internal cooling-air systems of gas turbine *** rotating-disc systems have been used successfully to simplify and understand some of the complex flows that occur in internal-air systems,and designers have used this insight to improve the cooling effectiveness,thereby increasing the engine efficiency and reducing the *** this review paper,three important cases are considered:hot-gas ingress;the pre-swirl system;and buoyancy-induced ***,or ingestion,occurs when hot gas from the mainstream gas path is ingested into the wheel-space between the turbine disc and its adjacent *** seals are fitted at the periphery of the system,and sealing flow is used to reduce or prevent ***,too much sealing air reduces the engine efficiency,and too little can cause serious overheating,resulting in damage to the turbine rim and blade *** the flow is three-dimensional and unsteady,there are encouraging signs that simple ‘orifice models’ could be used to estimate the amount of ingress into the *** a pre-swirl system,the cooling air for the gas-turbine blades is swirled by stationary nozzles,and the air is delivered to the blades via receiver holes in the rotating turbine *** the air reduces its temperature relative to the rotating blades,and the designer needs to calculate the air temperature and pressure drop in the *** designer also needs to calculate the effect of this swirling flow on the heat transfer from the turbine disc to the air,as this has a significant effect on the temperature distribution and stresses in the *** experimental and computational studies have given a better understanding of the flow and heat transfer in these ***-induced flow occurs in the cavity between two co-rotating compressor discs when the temperature of the discs is higher than

关键词：燃气涡轮机车空气动力学数学模型旋转式圆盘系统

Detailed characterization of kHz-rate laser-driven fusion at a thin liquid sheet with a neutron detection suite

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High Power Laser Science and Engineering 2024年第1期12卷 13-23页

作者： Benjamin M.Knight connor M.Gautam Colton R.Stoner Bryan V.Egner joseph R.Smith Chris M.orban juan j.Manfredi Kyle D.Frische Michael L.Dexter Enam A.Chowdhury Anil K.Patnaik Department of Engineering Physics Air Force Institute of TechnologyWPAFBOHUSA Physics Department Marietta CollegeMariettaOHUSA Department of Physics The Ohio State UniversityColumbusOHUSA Department of Materials Science and Engineering and Department of Electrical and Computer ScienceThe Ohio State UniversityColumbusOHUSA Intense Energy Solutions LLCPlain CityOHUSA

We present detailed characterization of laser-driven fusion and neutron production(-10^(5)/second) using 8 mj, 40 fs laser pulses on a thin(<1 μm) D_2o liquid sheet employing a measurement suite. At relativistic inte... 详细信息

We present detailed characterization of laser-driven fusion and neutron production(-10^(5)/second) using 8 mj, 40 fs laser pulses on a thin(o liquid sheet employing a measurement suite. At relativistic intensity(~ 5 × 10^(18)W/cm^(2))and high repetition rate(1 kHz), the system produces deuterium±deuterium(D-D) fusion, allowing for consistent neutron generation. Evidence of D-D fusion neutron production is verified by a measurement suite with three independent detection systems: an Ej-309 organic scintillator with pulse-shape discrimination, a ~3He proportional counter and a set of 36 bubble detectors. Time-of-flight analysis of the scintillator data shows the energy of the produced neutrons to be consistent with 2.45 MeV. Particle-in-cell simulations using the WarpX code support significant neutron production from D-D fusion events in the laser±target interaction region. This high-repetition-rate laser-driven neutron source could provide a low-cost, on-demand test bed for radiation hardening and imaging applications.

关键词： high-repetition-rate laser-driven fusion laser-plasma interaction liquid target neutron detectors

The Soft X-ray Imager(SXI)on the SMILE Mission

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Earth and Planetary Physics 2024年第1期8卷 5-14页

作者： S.Sembay A.L.Alme D.Agnolon T.Arnold A.Beardmore A.Belén Balado Margeli C.Bicknell C.Bouldin G.Branduardi-Raymont T.Crawford j.P.Breuer T.Buggey G.Butcher R.Canchal j.A.Carter A.Cheney Y.Collado-Vega H.connor T.Crawford N.Eaton C.Feldman C.Forsyth T.Frantzen G.Galgóczi j.Garcia G.Y.Genov C.Gordillo H-P.Gröbelbauer M.Guedel Y.Guo M.Hailey D.Hall R.Hampson j.Hasiba o.Hetherington A.Holland S-Y.Hsieh M.W.j.Hubbard H.jeszenszky M.jones T.Kennedy K.Koch-Mehrin S.Kögl S.Krucker K.D.Kuntz C.Lakin G.Laky o.Lylund A.Martindale j.Miguel Mas Hesse R.Nakamura K.oksavik N.Østgaard H.ottacher R.ottensamer C.Pagani S.Parsons P.Patel j.Pearson G.Peikert F.S.Porter T.Pouliantis B.H.Qureshi W.Raab G.Randal A.M.Read N.M.M.Roque M.E.Rostad C.Runciman S.Sachdev A.Samsonov M.Soman D.Sibeck S.Smit j.Søndergaard R.Speight S.Stavland M.Steller TianRan Sun j.Thornhill W.Thomas K.Ullaland B.Walsh D.Walton C.Wang S.Yang School of Physics and Astronomy University of LeicesterLeicesterLE17RHUK Space Park Leicester University of LeicesterLeicesterLE17RHUK Mullard Space Science Laboratory University College LondonDorkingRH56NTUK Centre for Electronic Imaging Open UniversityMilton KeynesMK76 AAUK Birkeland Centre for Space Science Department of Physics and TechnologyUniv.of BergenN-5007 BergenNorway University of Vienna A-1010 ViennaAustria Space Research Institute Austrian Academy of SciencesA-8042 GrazAustria National Institute of Aerospace Technology MadridSpain ESTEC European Space Agency2201 AZ NoordwijkNetherlands State Key Laboratory of Space Weather National Space Science CentreBeijing 100190China University of Applied Sciences and Arts Northwestern Switzerland CH-5210 WindischSwitzerland Koegl Space GmbH CH-8157 DielsdorfSwitzerland Space Acoustics GmbH CH-8157 DielsdorfSwitzerland Zurich University of Applied Sciences 8400 WinterhurSwitzerland Genov Solutions N-5172 LoddefjordNorway STM Engineering N-5165 LaksevagNorway john Hopkins University Applied Physics Laboratory MD 20723USA NASA/Goddard Space Flight Centre MD 20771USA Center for Space Physics Boston UniversityBostonMA 02215USA Department of Theoretical Physics and Astrophysics Masaryk University60177 BrnoCzech Republic Institute of Physics E¨otvo¨s Lor´and University1053 BudapestHungary Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100045China Centro de Astrobiologia(CAB) CSIC-INTAMadridSpain

The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)*** is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in *** is a compact X-ray telescope with a wide field-of-view(FoV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE *** is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s *** provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field *** sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many *** is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.

关键词： Soft X-ray Imaging micropore optics large area CCD