Standardization of a CT Protocol for Imaging Patients with Suspected COVID-19-A RACOON Project.

CT protocols that diagnose COVID-19 vary in regard to the associated radiation exposure and the desired image quality (IQ). This study aims to evaluate CT protocols of hospitals participating in the RACOON (Radiological Cooperative Network) project, consolidating CT protocols to provide recommendations and strategies for future pandemics. In this retrospective study, CT acquisitions of COVID-19 patients scanned between March 2020 and October 2020 (RACOON phase 1) were included, and all non-contrast protocols were evaluated. For this purpose, CT protocol parameters, IQ ratings, radiation exposure (CTDIvol), and central patient diameters were sampled. Eventually, the data from 14 sites and 534 CT acquisitions were analyzed. IQ was rated good for 81% of the evaluated examinations. Motion, beam-hardening artefacts, or image noise were reasons for a suboptimal IQ. The tube potential ranged between 80 and 140 kVp, with the majority between 100 and 120 kVp. CTDIvol was 3.7 ± 3.4 mGy. Most healthcare facilities included did not have a specific non-contrast CT protocol. Furthermore, CT protocols for chest imaging varied in their settings and radiation exposure. In future, it will be necessary to make recommendations regarding the required IQ and protocol parameters for the majority of CT scanners to enable comparable IQ as well as radiation exposure for different sites but identical diagnostic questions.

[The new radiation protection legislation-part 2 : Modifications in radiology regarding approval procedure and special fields including teleradiology]. / Die neue Strahlenschutzgesetzgebung ­ Teil 2 : Änderungen in der Radiologie bezüglich Vorabkontrolle und Sonderbereiche, einschließlich Teleradiologie.

BACKGROUND: The entry of the new Radiation Protection Act and new Radiation Protection Regulation into force in Germany created many changes for radiology with regard to the old Radiation Protection Regulation and X­ray Regulation. OBJECTIVES: The substantial modifications in radiology regarding the areas of approval and notification procedures, teleradiology, screening, research and radon in the workplace are summarized. METHOD: Changes in the new Radiation Protection Act and Regulation compared to the old Radiation Protection Regulation and X­ray Regulation were evaluated. Thereby, the focus was on areas beyond the workflow in clinical routine. RESULTS AND CONCLUSION: The requirements for the approval and notification procedure have increased. For example, proof must be provided that a medical physics expert can be consulted. The establishment of deadlines for the process by the responsible authorities may accelerate the procedure and create planning certainty.

[The new radiation protection legislation-part 1 : Modifications in radiology for the workflow in clinical routine]. / Die neue Strahlenschutzgesetzgebung ­ Teil 1 : Änderungen für die arbeitstägliche Routine in der Radiologie.

BACKGROUND: On 31 December 2018, the new Radiation Protection Regulation came into effect in Germany and made the new Radiation Protection Act more concrete. The old Radiation Protection Regulation and X­ray Regulation have thereby been replaced. OBJECTIVES: The substantial modifications regarding the practical daily routine in radiology are summarized. METHODS: Modifications and innovations of the New Radiation Protection Act and Regulation compared to the old Radiation Protection Regulation and X­ray Regulation and accordances were evaluated. Thereby the main focus was in the relevance for workflow in clinical routine. RESULTS AND CONCLUSION: The new legislation contains a number of regulations that provide crucial tools for implementation of radiation protection, quality assurance, and dose optimization. However, this also requires additional time and personnel.

Optimizing radiation exposure for CT localizer radiographs.

INTRODUCTION: The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. MATERIALS AND METHODS: The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDIvol and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. RESULTS: The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80kVp, 20mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. CONCLUSION: A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer.