2,298 research outputs found

    Quality assurance of radiodiagnostic equipment -Overview of literature since 2004

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    Het Britse handboek voor de kwaliteitsborging (Quality Assurance) van CT-scanners en andere rontgentoestellen, kan met enkele aanpassingen ook in Nederland gebruikt worden. Dit blijkt uit een literatuurstudie van het RIVM naar de kwaliteitsborging van deze apparaten. Beelden van CT-scanners en andere rontgentoestellen moeten goed genoeg zijn om een juiste diagnose te kunnen stellen. Ze worden gemaakt met rontgenstraling en die is schadelijk voor de gezondheid. De beelden worden echter vaak beter als er meer straling wordt gebruikt. Om goede beelden te krijgen met een zo laag mogelijke stralingsdosis is er veel aandacht nodig voor het optimaal laten functioneren van de apparatuur. Het geheel van maatregelen die hieraan bijdragen wordt kwaliteitsborging genoemd. Er is in Nederland geen algemeen handboek voor de kwaliteitsborging van CT-scanners en andere rontgenapparaten. Uit het onderzoek van het RIVM blijkt dat het Britse handboek, aangevuld met enkele andere documenten, vrij eenvoudig naar de Nederlandse praktijk vertaald kan worden. Wel is er nog een enkele toevoeging nodig en moeten grenswaarden worden aangepast aan de Nederlandse regelgeving.The British handbook on quality assurance of CT and other x-ray equipment may, with some adaptations, also be used in the Netherlands. This is the main conclusion of a literature study by RIVM on quality assurance of such equipment. Images from CT scanners and other x-ray equipment must have sufficient quality to enable a correct diagnosis. They are obtained using x-rays, which have adverse health effects. However, in diagnostic imaging, higher x-ray doses often lead to better image quality. To obtain good images while keeping the radiation dose as low as reasonably achievable, much attention is needed for the optimal performance of the equipment. Quality assurance is the complex of all measures needed to achieve this. A general handbook on quality assurance of CT and other x-ray equipment adapted to the Dutch practice does not exist. The literature study by RIVM shows that it should be relatively straightforward to adapt, with some additions, the British handbook to the Dutch practice and legislation.Inspectie voor de Gezondheidszor

    Digital mammography, cancer screening: Factors important for image compression

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    The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers

    Variations in signal-to-noise characteristics of tissue-equivalent attenuators for mammographic automatic exposure control system performance evaluation

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    PURPOSE: This work investigates the impact of tissue-equivalent attenuator choice on measured signal-to-noise ratio (SNR) for automatic exposure control (AEC) performance evaluation in digital mammography. It also investigates how the SNR changes for each material when used to evaluate AEC performance across different mammography systems. METHODS: AEC performance was evaluated for four mammography systems using seven attenuator sets at two thicknesses (4 and 8 cm). All systems were evaluated in 2D imaging mode, and one system was evaluated in digital breast tomosynthesis (DBT) mode. The methodology followed the 2018 ACR digital mammography quality control (DMQC) manual. Each system-attenuator-thickness combination was evaluated using For Processing images in ImageJ with standard ROI size and location. The closest annual physicist testing results were used to explore the impact of varying measured AEC performance on image quality. RESULTS: The measured SNR varied by 44%-54% within each system across all attenuators at 4 cm thickness in 2D mode. The variation appeared to be largely due to changes in measured noise, with variations of 46%-67% within each system across all attenuators at 4 cm thickness in 2D mode. Two systems had failing SNR levels for two of the materials using the minimum SNR criterion specified in the ACR DMQC manual. Similar trends were seen in DBT mode and at 8 cm thickness. Within each material, there was 115%-131% variation at 4 cm and 82%-114% variation at 8 cm in the measured SNR across the four imaging systems. Variation in SNR did not correlate with system operating level based on visual image quality and average glandular dose (AGD). CONCLUSION: Choice of tissue-equivalent attenuator for AEC performance evaluation affects measured SNR values. Depending on the material, the difference may be enough to result in failure following the longitudinal and absolute thresholds specified in the ACR DMQC manual

    SUSPENSION CRITERIA FOR IMAGE MONITORS AND VIEWING BOXES.

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    Image monitors and viewing boxes have a crucial role in the diagnostic process. Modern radiology uses different modalities to produce digital images which are to be viewed in different parts of the radiology department and throughout the hospital, sometimes simultaneously, via the Picture Archiving and Communications System (PACS). Therefore, the quality of the image monitors is of great importance. IPEM notes that inadequacies in the imaging viewing area may serve to negate the benefits of other efforts made to maintain quality and consistency. Suspension criteria for diagnostic image monitors and viewing boxes are presented in RP162. These criteria are mainly based on two documents, IPEM report 91, 'Recommended standards for the routine performance testing of diagnostic x-ray imaging systems' (2005) and AAPM on-line report no. 03, 'Assessment of display performance for medical imaging systems' (2005). The development of common European suspension levels for image monitors and viewing boxes will be a valuable tool in quality assurance

    Mammography Techniques and Review

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    Mammography remains at the backbone of medical tools to examine the human breast. The early detection of breast cancer typically uses adjunct tests to mammogram such as ultrasound, positron emission mammography, electrical impedance, Computer-aided detection systems and others. In the present digital era it is even more important to use the best new techniques and systems available to improve the correct diagnosis and to prevent mortality from breast cancer. The first part of this book deals with the electrical impedance mammographic scheme, ultrasound axillary imaging, position emission mammography and digital mammogram enhancement. A detailed consideration of CBR CAD System and the availability of mammographs in Brazil forms the second part of this book. With the up-to-date papers from world experts, this book will be invaluable to anyone who studies the field of mammography

    Mammography Services Quality Assurance: Baseline Standards for Latin America and the Caribbean

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    Fil: Barr, Helen. No especifíca;Fil: Blanco, Susana Alicia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Salud. Instituto Nacional del Cáncer; ArgentinaFil: Butler, Priscilla. No especifíca;Fil: da Paz, María Angela. No especifíca;Fil: Fleitas, Ileana. No especifíca;Fil: Craig, George. No especifíca;Fil: Jimenez, Pablo. No especifíca;Fil: Luciani, Silvana. No especifíca;Fil: Manrique, Javier. No especifíca;Fil: Mazal, Jonathan. No especifíca;Fil: Medlen, Kayiba. No especifíca;Fil: MIller, Colie. No especifíca;Fil: Mora, Patricia. No especifíca;Fil: Valdez Moreno, Martha Elena. No especifíca;Fil: Mosodeen, Murrie. No especifíca;Fil: Mysler, Gustavo. No especifíca;Fil: Nuche-Berenguer, Bernardo. No especifíca;Fil: Pastel, Mary. No especifíca;Fil: Pinochet, Miguel. No especifíca;Fil: Sisney, Gale. No especifíca;Fil: Ruiz Trejo, Cesar. No especifíca;Fil: Saraiya, Mona. No especifíca;Fil: Solis, Esteban. No especifíca;Fil: Swann, Phillip. No especifíca

    Regulation 61-64 x-rays (title B)

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    Except as otherwise specifically provided, this regulation applies to all persons who receive, possess, use, transfer, own, or acquire any x-ray producing machine. The provisions of this regulation shall not be interpreted as limiting the intentional exposure of patients to radiation for the purpose of diagnosis, analysis, or therapy by persons licensed to practice one (1) or more of the health professions within the authority granted to them by statute or regulation

    Focal Spot, Summer/Fall 2009

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    https://digitalcommons.wustl.edu/focal_spot_archives/1112/thumbnail.jp
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