1,522 research outputs found

    Diagnostic Reference Levels for digital mammography in Australia

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    Aims: In 3 phases, this thesis explores: radiation doses delivered to women during mammography, methods to estimate mean glandular dose (MGD), and the use of mammographic breast density (MBD) in MGD calculations. Firstly, it examines Diagnostic reference levels (DRLs) for digital mammography in Australia, with novel focus on the use of compressed breast thickness (CBT) and detector technologies as a guide when determining patient derived DRLs. Secondly, it analyses the agreement between Organ Dose estimated by different digital mammography units and calculated MGD for clinical data. Thirdly, it explores the novel use of MBD in MGD calculations, suggesting a new dose estimation called the actual glandular dose (AGD), and compares MGD to AGD. Methods: DICOM headers were extracted from 52405 anonymised mammograms using 3rd party software. Exposure and QA information were utilised to calculate MGD using 3 methods. LIBRA software was used to estimate MBD for 31097 mammograms. Median, 75th and 95th percentiles were calculated across MGDs obtained for all included data and according to 9 CBT ranges, average population CBT, and for 3 detector technologies. The significance of the differences, correlations, and agreement between MGDs for different CBT ranges, calculation methods, and different density estimation methods were analysed. Conclusions: This thesis have recommended DRLs for mammography in Australia, it shows that MGD is dependent upon CBT and detector technology, hence DRLs were presented as a table for different CBTs and detectors. The work also shows that Organ Doses reported by vendors vary from that calculated using established methodologies. Data produced also show that the use of MGD calculated using standardised glandularities underestimates dose at lower CBTs compared to AGD by up to 10%, hence, underestimating radiation risk. Finally, AGD was proposed; it considers differences in breast composition for individualised radiation-induced risk assessment

    Mean glandular dose values used for the mammography screening program in Poland according to the type of image registration system

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    Between 2007–2014, there have been considerable changes in the use of different types of detector systems at mammography facilities undertaking screening programs in Poland. The use of screen-film systems (termed SF systems) has largely decreased and been replaced by either computed radiography (termed CR systems) or digital radiography systems (termed DR systems); this inevitably affecting mean glandular dose values. The study aim was to evaluate changes of mean glandular dose values for a dose exposure of 4.5 cm (MGD4,5cmPMMA) achieved by using different image detectors. The study consisted of analysing 1499 protocols for quality control tests carried out by medical physicists at 16 Regional Coordination Offices in 2007, 2011, 2012 and 2013. The mean CR system values were higher than for SF systems; by 25% in 2011, by 26% in 2012, and by 28% in 2013. In subsequent years, the MGD4,5cmPMMA mean values for DR systems were higher than for SF systems by respectively 15%, 4% and 5%. Also in the subsequent years, the MGD4,5cmPMMA mean values for CR systems were higher than for DR systems by respectively 13%, 23% and 24%. In all cases, the MGD4,5cmPMMA mean values were within the acceptable level of 2.5 mGy. The MGD4,5cmPMMA mean values were different, depending on the detection system used for mammography screening in Poland

    The Establishment of Institutional Diagnostic Reference Levels (DRLs) in the Cipto Mangunkusumo Hospital

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    Institutional diagnostic reference levels are used for quality assurance in radiology departments. The purpose of this study was to establish an institutional diagnostic reference level (DRL) and to provide a practical tool in diagnostic radiology and nuclear medicine. For each type of procedure/examination, it needs at least 20 patients. The patients with regular size (average body size is 65 ± 10 kg for adult patients and 15±15 kg for pediatric patients) were enrolled in this project. The 75 percentile values of doses were used as institutional DRLs.  For nuclear medicine, the administered activities was based on the dose of activity to produce a good image. The DRL values were obtained for general radiography, nuclear medicine, mammography, CT examination, and interventional radiography. The DRL's result was compared to national DRL (NDRL) and values in other countries. The DRL values for general radiography in this study are higher compared to NDRL and Japanese study. The administered activities (MBq) for nuclear medicine in this study are higher compared to European Commission but lower when compared to a Japanese study. The DRL values for mammography in this study are higher compared to ARPANSA; however, they are lower than NDRL and UK studies. The DRL values for CT examination in this study are higher compared to Netherland, Canadian, and USA studies but lower than NDRL. The DRL values in interventional radiography (IR) in this study are lower compared to the IAEA study. This finding indicates that it is still necessary to optimize procedures in the future. The established institutional DRL values can be used as a tool for optimization

    Patients' expectations of the benefits and harms of treatments, screening, and tests a systematic review

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    IMPORTANCE Unrealistic patient expectations of the benefits and harms of interventions can influence decision making and may be contributing to increasing intervention uptake and health care costs. OBJECTIVE To systematically review all studies that have quantitatively assessed patients' expectations of the benefits and/or harms of any treatment, test, or screening test. EVIDENCE REVIEW A comprehensive search strategy was used in 4 databases (MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, PsycINFO) up to June 2013, with no language or study type restriction.We also ran cited reference searches of included studies and contacted experts and study authors. Two researchers independently evaluated methodological quality and extracted participants' estimates of benefit and harms and authors' contemporaneous estimates. FINDINGS Of the 15 343 records screened, 36 articles (from 35 studies) involving a total of 27 323 patients were eligible. Fourteen studies focused on a screen, 15 on treatment, 3 a test, and 3 on treatment and screening. More studies assessed only benefit expectations (22 [63%]) than benefit and harm expectations (10 [29%]) or only harm (3 [8%]). Fifty-four outcomes (across 32 studies) assessed benefit expectations: of the 34 outcomes with overestimation data available, the majority of participants overestimated benefit for 22 (65%) of them. For 17 benefit expectation outcomes, we could not calculate the proportion of participants who overestimated or underestimated, although for 15 (88%) of these, study authors concluded that participants overestimated benefits. Expectations of harm were assessed by 27 outcomes (across 13 studies): underestimation data were available for 15 outcomes and the majority of participants underestimated harm for 10 (67%) of these. A correct estimation by at least 50% of participants only occurred for 2 outcomes about benefit expectations and 2 outcomes about harm expectations. CONCLUSIONS AND RELEVANCE The majority of participants overestimated intervention benefit and underestimated harm. Clinicians should discuss accurate and balanced information about intervention benefits and harms with patients, providing the opportunity to develop realistic expectations and make informed decisions

    The TOMMY trial: a comparison of TOMosynthesis with digital MammographY in the UK NHS Breast Screening Programme--a multicentre retrospective reading study comparing the diagnostic performance of digital breast tomosynthesis and digital mammography with digital mammography alone.

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    BACKGROUND: Digital breast tomosynthesis (DBT) is a three-dimensional mammography technique with the potential to improve accuracy by improving differentiation between malignant and non-malignant lesions. OBJECTIVES: The objectives of the study were to compare the diagnostic accuracy of DBT in conjunction with two-dimensional (2D) mammography or synthetic 2D mammography, against standard 2D mammography and to determine if DBT improves the accuracy of detection of different types of lesions. STUDY POPULATION: Women (aged 47-73 years) recalled for further assessment after routine breast screening and women (aged 40-49 years) with moderate/high of risk of developing breast cancer attending annual mammography screening were recruited after giving written informed consent. INTERVENTION: All participants underwent a two-view 2D mammography of both breasts and two-view DBT imaging. Image-processing software generated a synthetic 2D mammogram from the DBT data sets. RETROSPECTIVE READING STUDY: In an independent blinded retrospective study, readers reviewed (1) 2D or (2) 2D + DBT or (3) synthetic 2D + DBT images for each case without access to original screening mammograms or prior examinations. Sensitivities and specificities were calculated for each reading arm and by subgroup analyses. RESULTS: Data were available for 7060 subjects comprising 6020 (1158 cancers) assessment cases and 1040 (two cancers) family history screening cases. Overall sensitivity was 87% [95% confidence interval (CI) 85% to 89%] for 2D only, 89% (95% CI 87% to 91%) for 2D + DBT and 88% (95% CI 86% to 90%) for synthetic 2D + DBT. The difference in sensitivity between 2D and 2D + DBT was of borderline significance (p = 0.07) and for synthetic 2D + DBT there was no significant difference (p = 0.6). Specificity was 58% (95% CI 56% to 60%) for 2D, 69% (95% CI 67% to 71%) for 2D + DBT and 71% (95% CI 69% to 73%) for synthetic 2D + DBT. Specificity was significantly higher in both DBT reading arms for all subgroups of age, density and dominant radiological feature (p < 0.001 all cases). In all reading arms, specificity tended to be lower for microcalcifications and higher for distortion/asymmetry. Comparing 2D + DBT to 2D alone, sensitivity was significantly higher: 93% versus 86% (p < 0.001) for invasive tumours of size 11-20 mm. Similarly, for breast density 50% or more, sensitivities were 93% versus 86% (p = 0.03); for grade 2 invasive tumours, sensitivities were 91% versus 87% (p = 0.01); where the dominant radiological feature was a mass, sensitivities were 92% and 89% (p = 0.04) For synthetic 2D + DBT, there was significantly (p = 0.006) higher sensitivity than 2D alone in invasive cancers of size 11-20 mm, with a sensitivity of 91%. CONCLUSIONS: The specificity of DBT and 2D was better than 2D alone but there was only marginal improvement in sensitivity. The performance of synthetic 2D appeared to be comparable to standard 2D. If these results were observed with screening cases, DBT and 2D mammography could benefit to the screening programme by reducing the number of women recalled unnecessarily, especially if a synthetic 2D mammogram were used to minimise radiation exposure. Further research is required into the feasibility of implementing DBT in a screening setting, prognostic modelling on outcomes and mortality, and comparison of 2D and synthetic 2D for different lesion types. STUDY REGISTRATION: Current Controlled Trials ISRCTN73467396. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 4. See the HTA programme website for further project information.This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 4. See the HTA programme website for further project information.Gilbert FJ, Tucker L, Gillan MGC, Willsher P, Cooke J, Duncan KA, et al. The TOMMY trial: a comparison of TOMosynthesis with digital MammographY in the UK NHS Breast Screening Programme – a multicentre retrospective reading study comparing the diagnostic performance of digital breast tomosynthesis and digital mammography with digital mammography alone. Health Technol Assess 2015;19(4). © Queen’s Printer and Controller of HMSO 2015. This work was produced by Gilbert et al. under the terms of a commissioning contract issued by the Secretary of State for Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should be addressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

    A review of mammographic positioning image quality criteria for the craniocaudal projection

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    Detection of breast cancer is reliant on optimal breast positioning and the production of quality images. Two projections, the mediolateral (MLO) and craniocaudal (CC), are routinely performed. Determination of successful positioning and inclusion of all breast tissue is achieved through meeting stated image quality criteria. For the CC view, current image quality criteria are inconsistent. Absence of reliable anatomical markers, other than the nipple, further contribute to difficulties in assessing the quality of CC views. The aim of this paper was to explore published international quality standards to identify and find the origin of any CC positioning criteria which might provide for quantitative assessment. The pectoralis major (pectoral) muscle was identified as a key posterior anatomical structure to establish optimum breast tissue inclusion on mammographic projections. It forms the first two of the three main CC metrics that are frequently reported 1. visualisation of the pectoral muscle, 2. measurement of the posterior nipple line (PNL) and 3. depiction of retroglandular fat. This literature review explores the origin of the three metrics, and discusses three key publications, spanning 1992 to 1994, on which subsequent image quality standards have been based. The evidence base to support published CC metrics is sometimes not specified and more often the same set of publications are cited, most often without critical evaluation. To conclude, there remains uncertainty if the metrics explored for the CC view support objective evaluation and reproducibility to confirm optimal breast positioning and quality images

    Patient exposure levels and collective effective dose to the population from radiological examinations - changes from 2008 to 2018 in Finland

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    Medical exposures from x-rays and nuclear medicine (NM) have been the largest man-made source of population exposure to ionizing radiation in developed countries for many years. A collective effective dose can be assessed by summarizing effective doses from all radiological examinations together. The collective effective dose is the product of the mean effective dose in a group and the number of individuals in that group. The most common method to assess effective doses per radiological examinations is to use application specific measurable quantities that are multiplied by predefined effective dose conversion factors. Frequencies of radiological examinations can be surveyed by questionnaires. In Finland the total collective effective dose from x-ray and NM procedures has increased 59% in 2008–2018, mainly due to the increase of collective effective doses from computed tomography (CT) and interventional radiology. The collective effective dose from NM examinations has slightly increased and its relative proportion is only 5% of the total collective dose from radiological examinations. About 70% of the collective effective dose from x-ray examinations was caused by CT in 2018, while the proportion of CT procedures was only 17%. CT procedures are the major and increasing source of collective effective dose from x-ray procedures. While the use of new tissue weighting factors (ICRP 103) increases the population dose from plain radiography, it has minimal effect on the population dose from CT examinations. There was a large amount of variation in the exposure levels and exposure parameters used for radiotherapy simulations. Patient exposure levels were generally much higher than those used for diagnostics. Exposure parameters should be reviewed and optimized together with the exposure level also for radiotherapy CT simulations. Effective doses per radiological examinations can be used to compare medical exposures from different methodologies or between different units or hospitals. Per caput doses can be compared between countries. In comparison with 36 European countries is was shown that frequencies of both x-ray and NM examinations in Finland were less than in average in Europe. This indicates that the level of justification in Finland is at least at the average European level. The comparison of per caput effective doses showed that the dose in Finland was on the lowest quarter among European countries. Despite of the increased collective effective dose from x-ray and NM examinations the overall per caput effective dose in Finland in 2018 was still well below the average of European countries in 2008 and only a third of the per caput effective dose in USA in 2016. This indicates that both justification and optimization of examinations in Finland is at a good European level
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