Author: Euclid Seeram
Publisher: Jones & Bartlett Publishers
Published: 2016-01-13
Total Pages: 599
ISBN-13: 1284117715
DOWNLOAD EBOOK →Radiation Protection in Diagnostic X-Ray Imaging covers the recent developments that have been introduced to address the increasing dose to the patient, and new assessment tools for use in dose optimization studies. Based on material from ASRT, ARRT and CAMRT, as well as Current Concepts of Radiation Protection. Content is mapped to the ARRT Radiation Protection Examination Specifications and ASRT Radiation Protection Objectives. In addition to topics prescribed by the ARRT for the certification examination, this book includes topics for advanced study. Some electronic and eBook versions do not include access to Navigate 2 Advantage resources.
Author: Lawrence Lau
Publisher: Springer Science & Business Media
Published: 2013-11-22
Total Pages: 473
ISBN-13: 9400772564
DOWNLOAD EBOOK →This book is the product of a unique collaboration by experts from leading international, regional and national agencies and professional organizations discussing on the current ‘hot’ issue on the judicious use and safety of radiation in radiology. There have been several cases involving radiation overexposure that have received international attention. Strategies and solutions to guide readers how to maximize the benefits and minimize the risks when using radiation in medicine are covered.
Author: Philip Doyle
Publisher:
Published: 2009
Total Pages:
ISBN-13:
DOWNLOAD EBOOK →Digital imaging has long been available in radiology in the form of computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Initially the transition to general radiography was slow and fragmented but in the last 10-15 years in particular, huge investment by the manufacturers, greater and cheaper computing power, inexpensive digital storage and high bandwidth data transfer networks have lead to an enormous increase in the number of digital radiography systems in the UK. There are a number of competing digital radiography (DR) technologies, the most common are computer radiography (CR) systems followed by indirect digital radiography (IDR) systems. To ensure and maintain diagnostic quality and effectiveness in the radiology department appropriate methods are required to evaluate and optimise the performance of DR systems. Current semi-quantitative test object based methods routinely used to examine DR performance suffer known short comings, mainly due to the subjective nature of the test results and difficulty in maintaining a constant decision threshold among observers with time. Objective image quality based measurements of noise power spectra (NPS) and modulation transfer function (MTF) are the 'gold standard' for assessing image quality. Advantages these metrics afford are due to their objective nature, the comprehensive noise analysis they permit and in the fact that they have been reported to be relatively more sensitive to changes in detector performance. The advent of DR systems and access to digital image data has opened up new opportunities in applying such measurements to routine quality control and this project initially focuses on obtaining NPS and MTF results for 12 IDR systems in routine clinical use. Appropriate automatic exposure control (AEC) device calibration and a reproducible measurement method are key to optimising X-ray equipment for digital radiography. The uses of various parameters to calibrate AEC devices specifically for DR were explored in the next part of the project and calibration methods recommended. Practical advice on dosemeter selection, measurement technique and phantoms were also given. A model was developed as part of the project to simulate CNR to optimise beam quality for chest radiography with an IDR system. The values were simulated for a chest phantom and adjusted to describe the performance of the system by inputting data on phosphor sensitivity, the signal transfer function (STF), the scatter removal method and the automatic exposure control (AEC) responses. The simulated values showed good agreement with empirical data measured from images of the phantom and so provide validation of the calculation methodology. It was then possible to apply the calculation technique to imaging of tissues to investigate optimisation of exposure parameters. The behaviour of a range of imaging phosphors in terms of energy response and variation in CNR with tube potential and various filtration options were investigated. Optimum exposure factors were presented in terms of kV-mAs regulation curves and the large dose savings achieved using additional metal filters were emphasised. Optimum tube potentials for imaging a simulated lesion in patient equivalent thicknesses of water ranging from 5-40 cm thick for example were: 90-110kVp for CsI (IDR); 80-100kVp for Gd2O2S (screen /film); and 65-85kVp for BaFBrI. Plots of CNR values allowed useful conclusions regarding the expected clinical operation of the various DR phosphors. For example 80-90 kVp was appropriate for maintaining image quality over an entire chest radiograph in CR whereas higher tube potentials of 100-110 kVp were indicated for the CsI IDR system. Better image quality is achievable for pelvic radiographs at lower tube potentials for the majority of detectors however, for gadolinium oxysulphide 70-80 kVp gives the best image quality. The relative phosphor sensitivity and energy response with tube potential were also calculated for a range of DR phosphors. Caesium iodide image receptors were significantly more sensitive than the other systems. The percentage relative sensitivities of the image receptors averaged over the diagnostic kV range were used to provide a method of indicating what the likely clinically operational dose levels would be, for example results suggested 1.8 μGy for CsI (IDR); 2.8 μGy for Gd2O2S (Screen/film); and 3.8 μGy for BaFBrI (CR). The efficiency of scatter reduction methods for DR using a range of grids and air gaps were also reviewed. The performance of various scatter reduction methods: 17/70; 15/80; 8/40 Pb grids and 15 cm and 20 cm air gaps were evaluated in terms of the improvement in CNR they afford, using two different models. The first, simpler model assumed quantum noise only and a photon counting detector. The second model incorporated quantum noise and system noise for a specific CsI detector and assumed the detector was energy integrating. Both models allowed the same general conclusions and suggest improved performance for air gaps over grids for medium to low scatter factors and both models suggest the best choice of grid for digital systems is the 15/80 grid, achieving comparable or better performance than air gaps for high scatter factors. The development, analysis and discussion of AEC calibration, CNR value, phosphor energy response, and scatter reduction methods are then brought together to form a practical step by step recipe that may be followed to optimise digital technology for clinical use. Finally, CNR results suggest the addition of 0.2 mm of copper filtration will have a negligible effect on image quality in DR. A comprehensive study examining the effect of copper filtration on image quality was performed using receiver operator characteristic (ROC) methodology to include observer performance in the analysis. A total of 3,600 observations from 80 radiographs and 3 observers were analysed to provide a confidence interval of 95% in detecting differences in image quality. There was no statistical difference found when 0.2 mm copper filtration was used and the benefit of the dose saving promote it as a valuable optimisation tool.
Author: Zubir Ahmad Shazli
Publisher: IIUM PRESS
Published: 2021-04-01
Total Pages: 90
ISBN-13: 9674911138
DOWNLOAD EBOOK →Optimization of dose in radiographic examinations is essential since the utilization of x-radiation is related to increased cancer risk. The study’s objective was to guide radiographers in ensuring best practices for common radiographic examinations of acceptable image quality in digital radiography while minimizing radiation doses that could result in harmful effects. The study comprised of three phases. The first phase involved 90 respondents between 20 to 60 years of age and weighing between 60-80 kilograms for the following examinations: anterior-posterior (AP) abdomen, AP or lateral lumbar sacral spine and posterior-anterior (PA) chest examinations. During this phase, the radiographic examination’s technical parameters for 30 radiographs for each examination were at the radiographers’ discretion. Kerma X_plus, DAP (dose area product) meter was utilized to evaluate the entrance surface dose (ESD), while CALDose_X 5.0 Monte Carlo was used to estimate the effective dose. The experimental study utilized an anthropomorphic phantom (PBU-50) and Leeds test object to compare the image quality. The best parameters were adapted to the patient’s AP thickness for the optimization study from the different technical parameters used in the experimental phase.
Author: Ehsan Samei
Publisher: Cambridge University Press
Published: 2018-12-13
Total Pages: 534
ISBN-13: 9781107194885
DOWNLOAD EBOOK →A state-of-the-art review of key topics in medical image perception science and practice, including associated techniques, illustrations and examples. This second edition contains extensive updates and substantial new content. Written by key figures in the field, it covers a wide range of topics including signal detection, image interpretation and advanced image analysis (e.g. deep learning) techniques for interpretive and computational perception. It provides an overview of the key techniques of medical image perception and observer performance research, and includes examples and applications across clinical disciplines including radiology, pathology and oncology. A final chapter discusses the future prospects of medical image perception and assesses upcoming challenges and possibilities, enabling readers to identify new areas for research. Written for both newcomers to the field and experienced researchers and clinicians, this book provides a comprehensive reference for those interested in medical image perception as means to advance knowledge and improve human health.
Author: Suhny Abbara, MD, FACR, FSCCT
Publisher: Elsevier Health Sciences
Published: 2012-12-11
Total Pages: 873
ISBN-13: 1437727689
DOWNLOAD EBOOK →Optimize diagnostic accuracy with Cardiovascular Imaging, a title in the popular Problem Solving in Radiology series. Drs. Suhny Abbara and Sanjeeva Kalva use a problem-based approach to help you make optimal use of the latest cardiovascular imaging techniques and achieve confident diagnoses. Make the most effective use of today's imaging techniques, including PET and SPECT. Perform effective interventions using the newest grafts, stents, and coils. See conditions as they appear in practice with more than 2,350 images detailing anatomy, normal anatomic variants, and pathology. Make optimal clinical choices and avoid complications with expert protocols and tricks of the trade. Avoid common problems that can lead to an incorrect diagnosis. Tables and boxes with tips, pitfalls, and other teaching points show you what to look for, while problem-solving advice helps you make sound clinical decisions. Quickly find the information you need thanks to a well-organized, user-friendly format with consistent headings, detailed illustrations, and at-a-glance tables. Access the entire text and illustrations online at www.expertconsult.com.
Author:
Publisher:
Published: 2015
Total Pages: 116
ISBN-13:
DOWNLOAD EBOOK →Cardiovascular disease and stroke are the leading health problems and causes of death in the US. Due to the minimally invasive nature of the evolution of image guided techniques, interventional radiological procedures are becoming more common and are preferred in treating many cardiovascular diseases and strokes. In addition, with the recent advances in hardware and device technology, the speed and efficacy of interventional treatment has significantly improved. This implies that more image modalities can be developed based on the current C-arm system and patients treated in interventional suites can potentially experience better health outcomes. However, during the treatment patients are irradiated with substantial amounts of ionizing radiation with a high dose rate (digital subtraction angiography (DSA) with 3$\mu$Gy/frame and 3D cone beam CT image with 0.36$\mu$Gy/frame for a Siemens Artis Zee biplane system) and/or a long irradiation time (a roadmapping image sequence can be as long as one hour during aneurysm embolization). As a result, the patient entrance dose is extremely high. Despite the fact that the radiation dose is already substantial, image quality is not always satisfactory. By default a temporal average is used in roadmapping images to overcome poor image quality, but this technique can result in motion blurred images. Therefore, reducing radiation dose while maintaining or even improving the image quality is an important area for continued research. This thesis is focused on improving the clinical applications of C-arm cone beam CT systems in two ways: (1) Improve the performance of current image modalities on the C-arm system. (2) Develop new image modalities based on the current system. To be more specific, the objectives are to reduce radiation dose for current modalities (e.g., DSA, fluoroscopy, roadmapping, and cone beam CT) and enable cone beam CT perfusion and time resolved cone beam CT angiography that can be used to diagnose and triage acute ischemic stroke patients more efficiently compared with the current clinical work-flow. The animal and patient cases presented in this thesis are focused towards but not limited to neurointerventional applications.
Author: Olaf Dössel
Publisher: Springer Science & Business Media
Published: 2010-01-01
Total Pages: 716
ISBN-13: 3642039022
DOWNLOAD EBOOK →Present Your Research to the World! The World Congress 2009 on Medical Physics and Biomedical Engineering – the triennial scientific meeting of the IUPESM - is the world’s leading forum for presenting the results of current scientific work in health-related physics and technologies to an international audience. With more than 2,800 presentations it will be the biggest conference in the fields of Medical Physics and Biomedical Engineering in 2009! Medical physics, biomedical engineering and bioengineering have been driving forces of innovation and progress in medicine and healthcare over the past two decades. As new key technologies arise with significant potential to open new options in diagnostics and therapeutics, it is a multidisciplinary task to evaluate their benefit for medicine and healthcare with respect to the quality of performance and therapeutic output. Covering key aspects such as information and communication technologies, micro- and nanosystems, optics and biotechnology, the congress will serve as an inter- and multidisciplinary platform that brings together people from basic research, R&D, industry and medical application to discuss these issues. As a major event for science, medicine and technology the congress provides a comprehensive overview and in–depth, first-hand information on new developments, advanced technologies and current and future applications. With this Final Program we would like to give you an overview of the dimension of the congress and invite you to join us in Munich! Olaf Dössel Congress President Wolfgang C.