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For risk estimations, scientists have at their disposition results from molecular, cellular and animal experiments, risk modelling and human epidemiological studies. Much has been achieved, but large uncertainties in quantitative risk estimates of exposure of humans to low levels of ionising radiation still remain. Radiation risks in diagnostic radiology are reviewed in this paper. The paper addresses stochastic as well as deterministic effects. Risks for adult, paediatric and prenatal exposures are discussed. It is concluded that a pragmatic approach for radiation protection in diagnostic radiology is indicated, i.e. precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically. [ABSTRACT FROM AUTHOR]

Objective: To implement detailed EU cardiac computed tomography angiography (CCTA) quality criteria in the multicentre DISCHARGE trial (FP72007-2013, EC-GA 603266), we reviewed image quality and adherence to CCTA protocol and to the recommendations of invasive coronary angiography (ICA) in a pilot study., Materials and Methods: From every clinical centre, imaging datasets of three patients per arm were assessed for adherence to the inclusion/exclusion criteria of the pilot study, predefined standards for the CCTA protocol and ICA recommendations, image quality and non-diagnostic (NDX) rate. These parameters were compared via multinomial regression and ANOVA. If a site did not reach the minimum quality level, additional datasets had to be sent before entering into the final accepted database (FADB)., Results: We analysed 226 cases (150 CCTA/76 ICA). The inclusion/exclusion criteria were not met by 6 of the 226 (2.7%) datasets. The predefined standard was not met by 13 of 76 ICA datasets (17.1%). This percentage decreased between the initial CCTA database and the FADB (multinomial regression, 53 of 70 vs 17 of 75 [76%] vs [23%]). The signal-to-noise ratio and contrast-to-noise ratio of the FADB did not improve significantly (ANOVA, p = 0.20; p = 0.09). The CTA NDX rate was reduced, but not significantly (initial CCTA database 15 of 70 [21.4%]) and FADB 9 of 75 [12%]; p = 0.13)., Conclusion: We were able to increase conformity to the inclusion/exclusion criteria and CCTA protocol, improve image quality and decrease the CCTA NDX rate by implementing EU CCTA quality criteria and ICA recommendations., Key Points: • Failure to meet protocol adherence in cardiac CTA was high in the pilot study (77.6%). • Image quality varies between sites and can be improved by feedback given by the core lab. • Conformance with new EU cardiac CT quality criteria might render cardiac CTA findings more consistent and comparable.

Objectives: More than 3.5 million invasive coronary angiographies (ICA) are performed in Europe annually. Approximately 2 million of these invasive procedures might be reduced by noninvasive tests because no coronary intervention is performed. Computed tomography (CT) is the most accurate noninvasive test for detection and exclusion of coronary artery disease (CAD). To investigate the comparative effectiveness of CT and ICA, we designed the European pragmatic multicentre DISCHARGE trial funded by the 7th Framework Programme of the European Union (EC-GA 603266)., Methods: In this trial, patients with a low-to-intermediate pretest probability (10-60 %) of suspected CAD and a clinical indication for ICA because of stable chest pain will be randomised in a 1-to-1 ratio to CT or ICA. CT and ICA findings guide subsequent management decisions by the local heart teams according to current evidence and European guidelines., Results: Major adverse cardiovascular events (MACE) defined as cardiovascular death, myocardial infarction and stroke as a composite endpoint will be the primary outcome measure. Secondary and other outcomes include cost-effectiveness, radiation exposure, health-related quality of life (HRQoL), socioeconomic status, lifestyle, adverse events related to CT/ICA, and gender differences., Conclusions: The DISCHARGE trial will assess the comparative effectiveness of CT and ICA., Key Points: • Coronary artery disease (CAD) is a major cause of morbidity and mortality. • Invasive coronary angiography (ICA) is the reference standard for detection of CAD. • Noninvasive computed tomography angiography excludes CAD with high sensitivity. • CT may effectively reduce the approximately 2 million negative ICAs in Europe. • DISCHARGE addresses this hypothesis in patients with low-to-intermediate pretest probability for CAD.

The purpose of this study was to assess contrast-detail performance and effective dose of eight different digital chest radiography systems. Digital chest radiography systems from different manufacturers were included: one storage phosphor system, one selenium-coated drum system, and six direct readout systems including four thin-film transistor (TFT) systems and two charge-coupled device (CCD) systems. For measuring image quality, a contrast-detail test object was used in combination with a phantom that simulates the primary and scatter transmission through lung fields (LucAl). Six observers judged phantom images of each modality by soft-copy reading in a four-alternative-forced-choice experiment. The entrance dose was also measured, and the effective dose was calculated for an average patient. Contrast-detail curves were constructed from the observer data. The blocked two-way ANOVA test was used for statistical analysis. Significant difference in contrast-detail performance was found between the systems. Best contrast-detail performance was shown by a CCD system with slot-scan technology, and the selenium-coated drum system was compared to the other six systems (p values

The purpose of this study was to determine and compare the effective dose of multidetector computed tomographic angiography (MDCT) and digital subtraction angiography (DSA) studies for diagnosing a pulmonary embolus (PE). Radiation exposure was measured as computed tomography dose index (MDCT) or as dose-area product (DSA) and was subsequently expressed in the quantity effective dose. Effective doses were obtained in 27 patients who underwent MDCT and in 12 patients who underwent DSA for suspected PE. The MDCT angiography was performed on a Siemens Volume Zoom CT scanner and DSA on a Philips Integris V-3000 system according to standardized protocols. Average effective dose for MDCT angiography of the pulmonary arteries (27 patients) was 4.2 mSv (range 2.2-6.0 mSv). Pulmonary DSA gained an average effective dose (12 patients) of 7.1 mSv (range 3.3-17.3 mSv). Our results show that the effective doses in MDCT angiography studies for PE are moderate and even slightly lower in comparison with pulmonary DSA in a comparable patient group. Variations in patient dose are smaller for MDCT, probably because this procedure can be more strictly protocolized. Patient dose should not be restrictive in the discussion of CTA replacing DSA for diagnosing PE.