Abstract: Since the first Oxford Survey of Childhood Cancer’s results were published, people have become more aware of the risks associated with prenatal exposure from diagnostic x rays. As a result, it has since been the subject of many studies. In this review, the results of recent epidemiological studies are summarized. The current international guidelines for diagnostic x-ray examinations were compared to the review. All epidemiological studies starting from 2007 and all relevant international guidelines were included. Apart from one study that involved rhabdomyosarcoma, no statistically significant associations were found between prenatal exposure to x rays and the development of cancer during 2007–2020. Most of the studies were constrained in their design due to too small a cohort or number of cases, minimal x-ray exposure, and/or data obtained from the exposed mothers instead of medical reports. In one of the studies, computed tomography exposure was also included, and this requires more and longer follow-up in successive studies. Most international guidelines are comparable, provide risk coefficients that are quite conservative, and discourage abdominal examinations of pregnant women.
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Diagnostic reference levels (DRLs) for medical x-ray procedures are being implemented currently in the Netherlands. By order of the Dutch Healthcare Inspectorate, a survey has been conducted among 20 Dutch hospitals to investigate the level of implementation of the Dutch DRLs in current radiological practice. It turns out that hospitals are either well underway in implementing the DRLs or have already done so. However, the DRLs have usually not yet been incorporated in the QAsystem of the department nor in the treatment protocols. It was shown that the amount of radiation used, as far as it was indicated by the hospitals, usually remains below the DRLs. A procedure for comparing dose levels to the DRLs has been prescribed but is not Always followed in practice. This is especially difficult in the case of children, as most general hospitals receive few children. Health Phys. 108(4):462–464; 2015
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Introduction: The Netherlands does not have a national guideline for performing radiographic examinations on pregnant patients. Radiographic examination is a generic term for all examinations performed using ionizing radiation, including but not limited to radiographs, fluoroscopy and computed tomography. A pilot study amongst radiographers (Medical Radiation Technologists (MRTs)) showed that standardized practice of radiographic examinations on pregnant women is not evident between Radiology departments and that there is a need for a national guideline as the varying practice methods may lead to confusion and uncertainty amongst both patients and MRTs. Methods: Focus groups consisting of MRTs from several Radiology departments within the Netherlands were used to map ideas and requirements as to what should be included in the national guideline. Nine focus group sessions were organized with a total of 52 participants. Using a previous review (Wit, Fleur; Vroonland, Colinda; Bijwaard H. Pre-natal X-ray exposure and the risk of developing paediatric cancer; a systematic review of risk factors and a comparison of international guidelines. Health Physics 2021; 121 (3):225e233), the following key points were chosen as discussion topics for the focus group sessions: dose reduction, confirming pregnancy and risk communication. Results: Results showed that the participating MRTs did not agree on the use of lead aprons. That the national guideline should include standardized methods to adjust parameters to decrease radiation dose. Focus group participants find it difficult to ask a patient's pregnancy status, especially when dealing with relatively young and old (er) patients. When communicating the level of risk associated with a radiographic examination the participating MRTs would like to be able to use examples and comparisons, preferably by means of a multilingual website. Conclusion: A national guideline must include information on justification, available alternatives, dose reductions methods and confirmation of pregnancy requirements when fetal dose is a significant risk. Implications for practice: A national guideline ensures standardized practice can be implemented in Radiology departments, increasing clarity of the issues for both patients and MRTs.
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In this project, Photons in Focus, researchers from The Hague University of Applied Sciences will work together with the company Photosynthetic to fabricate high-quality microlenses that will optimally focus light onto microscopic light detectors. Specifically, the microlenses will be designed to focus light onto superconducting nanowire single-photon detectors (SNSPDs) from the company Single Quantum. SNSPDs are cryogenic single-photon detectors with photon detection efficiencies up to 99% and timing resolutions down to 15 picosecond. Recently, Single Quantum has been developing arrays of SNSPDs for free-space biomedical imaging and deep space communications. The photon detection efficiency of these arrays is suboptimal, because 15-20% of the light falls onto nonsensitive areas. In Photons in Focus, fabrication of two types of microstructures will be explored for optimally focusing light onto these SNSPDs and improving the photon detection efficiency. First, 3-dimensional microlenses will be created at Photosynthetic using their method of dual-wavelength volumetric microlithography. Second, phase-reversal Fresnel zone plates will be fabricated using standard 2-dimensional photolithography at The Hague University of Applied Sciences. Both types of microstructures will be tested for their focusing properties and potential optical losses, and their ability to enhance to photon detection efficiency of SNSPDs in cryogenic conditions.
The demand for mobile agents in industrial environments to perform various tasks is growing tremendously in recent years. However, changing environments, security considerations and robustness against failure are major persistent challenges autonomous agents have to face when operating alongside other mobile agents. Currently, such problems remain largely unsolved. Collaborative multi-platform Cyber- Physical-Systems (CPSs) in which different agents flexibly contribute with their relative equipment and capabilities forming a symbiotic network solving multiple objectives simultaneously are highly desirable. Our proposed SMART-AGENTS platform will enable flexibility and modularity providing multi-objective solutions, demonstrated in two industrial domains: logistics (cycle-counting in warehouses) and agriculture (pest and disease identification in greenhouses). Aerial vehicles are limited in their computational power due to weight limitations but offer large mobility to provide access to otherwise unreachable places and an “eagle eye” to inform about terrain, obstacles by taking pictures and videos. Specialized autonomous agents carrying optical sensors will enable disease classification and product recognition improving green- and warehouse productivity. Newly developed micro-electromechanical systems (MEMS) sensor arrays will create 3D flow-based images of surroundings even in dark and hazy conditions contributing to the multi-sensor system, including cameras, wireless signatures and magnetic field information shared among the symbiotic fleet. Integration of mobile systems, such as smart phones, which are not explicitly controlled, will provide valuable information about human as well as equipment movement in the environment by generating data from relative positioning sensors, such as wireless and magnetic signatures. Newly developed algorithms will enable robust autonomous navigation and control of the fleet in dynamic environments incorporating the multi-sensor data generated by the variety of mobile actors. The proposed SMART-AGENTS platform will use real-time 5G communication and edge computing providing new organizational structures to cope with scalability and integration of multiple devices/agents. It will enable a symbiosis of the complementary CPSs using a combination of equipment yielding efficiency and versatility of operation.
