3D printed biomedical devices and their applications: A review on state-of-the-art technologies, existing challenges, and future perspectives

3D printing, also known as Additive manufacturing (AM), has emerged as a transformative technology with applications across various industries, including the medical sector. This review paper provides an overview of the current status of AM technology, its challenges, and its application in the medical industry. The paper covers the different types of AM technologies, such as fused deposition modeling, stereolithography, selective laser sintering, digital light processing, binder jetting, and electron beam melting, and their suitability for medical applications. The most commonly used biomedical materials in AM, such as plastic, metal, ceramic, composite, and bio-inks, are also viewed. The challenges of AM technology, such as material selection, accuracy, precision, regulatory compliance, cost and quality control, and standardization, are also discussed. The review also highlights the various applications of AM in the medical sector, including the production of patient-specific surgical guides, prosthetics, orthotics, and implants. Finally, the review highlights the Internet of Medical Things (IoMT) and artificial intelligence (AI) for regulatory frameworks and safety standards for 3D-printed biomedical devices. The review concludes that AM technology can transform the healthcare industry by enabling patients to access more personalized and reasonably priced treatment alternatives. Despite the challenges, integrating AI and IoMT with 3D printing technology is expected to play a vital role in the future of biomedical device applications, leading to further advancements and improvements in patient care. More research is needed to address the challenges and optimize its use for medical applications to utilize AM's potential in the medical industry fully.

Effectiveness of the revision to FMVSS 301: FARS and NASS-CDS analysis of fatalities and severe injuries in rear impacts

PURPOSE

This study investigated the change in the fatality and severe injury risks in rear impacts with vehicle model years (MY) grouped prior to, during the phase-in and after the revision to FMVSS 301.

METHODS

FARS and NASS-CDS data were used to determine the injury risks of non-ejected occupants in light vehicles involving non-rollover, rear impacts. The data were analyzed by MY groups: 1996-2001, 2002-2007 and 2008+ to represent the years prior to, during the phase-in and post-revision phase-in of FMVSS 301. The 1996-2013 FARS data were analyzed for rear crashes defined by the initial crash direction (IMPACT1) and direction with most damage (IMPACT2) to the rear. Fatality risk was determined by the number of fatally injured occupants per all occupants with known injury status. The 1994-2013 NASS-CDS was analyzed for rear crashes defined by the damage area variable. The risk of severe injury (MAIS 4+F) was determined as the number of occupants with MAIS 4+F injury per all occupants with known injury status. The distribution of rear crashes was determined by impact location and crash severity. NASS-CDS electronic cases with 2008+ MY vehicles were analyzed to evaluate the vehicle and occupant performance.

RESULTS

The fatality risk was 20.6% in the 1996-2001, 17.3% in the 2002-2007 and 15.0% in the 2008+ MY vehicles using FARS with the initial crash direction variable (IMPACT1) to the rear. There was a 27.1% reduction in risk with post-FMVSS 301 vehicles 2008+ MY. The risk was 19.0%, 15.4% and 12.8% with the most damage variable (IMPACT2) to the rear. There was 32.8% reduction in risk with 2008+ MY vehicles. The NASS-CDS analysis showed that the risk of severe injury (MAIS 4+F) was 0.27±0.05% for 1996-2001, 0.30±0.13% for 2002-2007 and 0.08±0.04% for 2008+ MY year vehicles. There was a 70.2% reduction in the risk for severe injury with 2008+ MY vehicles. The NASS-CDS case review of MAIS 4+F injury in rear impacts of 2008+ MY vehicles that comply with the revised FMVSS 301 indicated that the crashes were very severe and generally involved significant 2nd row intrusion.

CONCLUSIONS

The revision to FMVSS 301 has effectively reduced the risks for fatal and severe injury in vehicles compliant with the revision (2008+ MY). The reduction was 27.1-32.8% in fatality risk using FARS data and 70.2% in severe injury risk using the NASS-CDS when compared to vehicles prior to the phase-in of the revised FMVSS 301 (1996-2001 MY vehicles). It is not possible to parse the effects of other design changes in seats and restraint systems that also increased safety over the study years.

ESR EuroSafe Imaging and its role in promoting radiation protection - 6 years of success

This article introduces the European Society of Radiology’s EuroSafe Imaging initiative in the year of its 6th anniversary. The European and global radiation protection frameworks are outlined and the role of the EuroSafe Imaging initiative’s Call for Action in successfully achieving international radiation protection goals as set out by those frameworks is detailed.

Impact Performance of Certified Bicycle Helmets Below, On and Above the Test Line

Bicycle helmets are effective in reducing many head injuries, but their effectiveness could be improved if they provided protection over a larger range of impact locations. We sought to quantify the impact performance of 12 helmet models below, on and above the CPSC prescribed test line. All helmets were drop tested at an impact speed of 6.2 m/s. One helmet adequately attenuated impacts below the CPSC limit of 300 g for all impact locations tested below, on and above the test line. Five helmets met this limit for impacts on or above the test line as required in the CPSC standard, but failed to meet it below the test line (not required in the standard). The remaining six helmets failed to meet the criterion on and/or above the test line. Our findings indicate that consumers should not assume that all portions of a helmet provide adequate and equivalent protection. Our findings also suggest that the CPSC's current system of self-regulation and self-testing by manufacturers does not prevent substandard bicycle helmets from being sold. Public availability of manufacturers' impact test data, an independent testing panel, and/or a wider distribution of impact locations are needed to better protect bicyclists.

Analysis of mechanics of side impact test defined in UN/ECE Regulation 129

OBJECTIVE

This article discusses differences between a side impact procedure described in United Nations/Economic Commission for Europe (UN/ECE) Regulation 129 and scenarios observed in real-world cases.

METHODS

Numerical simulations of side impact tests utilizing different boundary conditions are used to compare the severity of the Regulation 129 test and the other tests with different kinematics of child restraint systems (CRSs). In the simulations, the authors use a validated finite element (FE) model of real-world CRSs together with a fully deformable numerical model of the Q3 anthropomorphic test device (ATD) by Humanetics Innovative Solution, Inc.

RESULTS

The comparison of 5 selected cases is based on the head injury criterion (HIC) index. Numerical investigations reveal that the presence of oblique velocity components or the way in which the CRS is mounted to the test bench seat fixture is among the significant factors influencing ATD kinematics. The results of analyses show that the side impact test procedure is very sensitive to these parameters. A side impact setup defined in Regulation 129 may minimize the effects of the impact.

CONCLUSIONS

It is demonstrated that an artificial anchorage in the Regulation 129 test does not account for a rotation of the CRS, which should appear in the case of a realistic anchorage. Therefore, the adopted procedure generates the smallest HIC value, which is at the level of the far-side impact scenario where there are no obstacles. It is also shown that the presence of nonlateral acceleration components challenges the quality of a CRS and its headrest much more than a pure lateral setup.

Impact of Sterilization Methods on the Seeding Ability of Human Tau Proteopathic Seeds

The protein tau, when misfolded in neurodegenerative diseases, has several prion-like properties including being able to spread by cell-to-cell transfer, induce templated seeding, and exist in distinct conformational strains. These properties of transmission may present health hazards when lesion-containing biospecimens are used in research and neuropathology laboratories. We evaluated the impact standard sterilization and cleaning methods have on the capacity of tau seeds to induce aggregation. We employed a previously developed, highly sensitive FRET-based biosensor assay to assess remnant tau seeding after exposure to these procedures. For tau species derived from human Alzheimer disease tissue (brain homogenate and sarkosyl-insoluble fibrils), both autoclaving and incubation in 90.6% formic acid were sufficient to reduce tau bioactivity. By contrast, boiling was not always effective in completely blocking bioactivity in the seeding assay. Notably, only formic acid incubation was able to produce a similar reduction in tissue from a P301L mutant tau mouse model of tauopathy. Our study highlights nuances in methods for inactivation of tau seeding which may support adapted tissue processing procedures, especially in research settings. These findings also highlight the importance of universal precautions when handling human neuropathological and research laboratory materials.

Reflections on chemical risk assessment or how (not) to serve society with science

In this paper, we want to shed light on the demand for chemical and toxicological data growing ever more faster than science can supply and other aspects of assessing chemical risks, including the demand for 'ever greater safety'. The treatise that follows is on the one hand rooted in well-established toxicological theory and on the other hand utilises emerging toxicological insights. Both theoretical conceptions and empirical substantiations are discussed to build up a perspective that produces an outlook on innovation and proliferates insights into our inexorable and invaluable exposure to 'the chemical'. We propose that in toxicology, with the implicit mandatory linear routine of dose-response, there is no tangible scientific drive to understand and unearth the actual empirical dose-response curve for chemicals under scrutiny. This can and should be improved upon as to advance the science of toxicology and to optimise current and future regulatory efforts.

Non-linear Wave Propagation and Safety Standards for Diagnostic Ultrasound Devices

Safety standards for clinical diagnostic ultrasonic devices were developed for use in relatively low-frequency systems (1-10 MHz), under the assumption that non-linear effects would be negligible. This article reviews ways in which neglecting non-linear wave propagation affects the measurements and calculations required to comply with safety standards and U.S. Food and Drug Administration guidance that recognizes these standards. An attempt is made to evaluate whether ignoring non-linear effects could result in significant error in the exposure quantities defined in these standards at either low or high frequencies, based on published literature. This article maintains that although non-linear effects have been considered in some parts of safety standards related to hydrophone requirements, the coverage is inadequate, especially for modern equipment with high working frequencies. A new approach is required to assess the magnitude of thermal heating for recently developed high-frequency systems to incorporate non-linear effects. In contrast, the current approach for evaluating the risk of cavitation can be used after appropriate modifications.

Ergo, SMIRK is safe: a safety case for a machine learning component in a pedestrian automatic emergency brake system

Integration of machine learning (ML) components in critical applications introduces novel challenges for software certification and verification. New safety standards and technical guidelines are under development to support the safety of ML-based systems, e.g., ISO 21448 SOTIF for the automotive domain and the Assurance of Machine Learning for use in Autonomous Systems (AMLAS) framework. SOTIF and AMLAS provide high-level guidance but the details must be chiseled out for each specific case. We initiated a research project with the goal to demonstrate a complete safety case for an ML component in an open automotive system. This paper reports results from an industry-academia collaboration on safety assurance of SMIRK, an ML-based pedestrian automatic emergency braking demonstrator running in an industry-grade simulator. We demonstrate an application of AMLAS on SMIRK for a minimalistic operational design domain, i.e., we share a complete safety case for its integrated ML-based component. Finally, we report lessons learned and provide both SMIRK and the safety case under an open-source license for the research community to reuse.

Application of a pharmacokinetic model in characterizing sources of polychlorinated biphenyl exposure and determining threshold daily intakes for adverse health effects in infants and toddlers

Characterization of PCB exposure sources for vulnerable population groups is essential to minimize the health effects of PCB exposure. At the same time, it is important to consolidate the knowledge on threshold intakes of PCBs for infants and toddlers to prevent health effects. We estimated total PCB concentrations from birth to 2 years of age in children from Slovak and Czech populations, which continue to have high PCB concentrations in breast milk. Using a pharmacokinetic (PK) model, we characterized dominant PCB exposure sources and estimated new threshold estimated daily intakes (TEDI) (above which adverse effects cannot be excluded) for postnatal PCB exposure in infants and toddlers. In the PK model, concentrations of seven indicator PCBs in breast milk and cord blood samples from 291 mother-child pairs from the Slovak birth cohort, and 396 breast milk samples from Czech mothers we used, together with their physiological characteristics and PCB concentrations from other exposure sources (food, dust, air). The estimated total PCB concentrations in children's blood at different ages were compared with threshold PCB concentrations of 500, 700 and 1000 ng·g_lipid^-1 in serum proposed by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) and the German Environment Agency (UBA), above which possible adverse health effects may be expected. We estimated that up to 20.6% of Slovak children and up to 45.7% of Czech children at two years of age exceeded the threshold value of 700 ng·g_lipid^-1 in blood. Mean TEDIs leading to values of 500 ng·g_lipid^-1 in blood for children up to two years ranged between 110 and 220 ng·kg^-1·bw·day^-1, varying according to breastfeeding duration. Breast milk and prenatal exposure contributed to 71%-85% of PCBs exposure at two years of age. In contrast, the contributions of PCBs from dust and indoor air were negligible.

The new Basic Safety Standards Directive and its implications for environmental monitoring

Monitoring of levels of radioactivity in the environment is enshrined in Chapter 3 of the Euratom Treaty, in particular its Articles 35 and 36. These requirements in primary law have had an important impact on the importance of monitoring in Europe but have not been worked out in much detail in secondary legislation. The consolidation and revision of the Basic Safety Standards Directive was an opportunity for doing so. The requirements in Directive 96/29/Euratom had remained rather general. Now, more specific text is introduced on the establishment of discharge authorisations for radioactive effluents, and on monitoring these discharges. Requirements on estimation of public exposures and on environmental monitoring programmes have largely been copied from the old basic safety standards (BSS), however. The main novelty of the new BSS is the introduction of exposure situations, as defined by the ICRP in Publication 103 (2007). Environmental monitoring as part of the management of an emergency exposure situation is now addressed more clearly. As for existing exposure situations, indoor exposure to radon requires extensive surveys of indoor air or soil concentrations, and precise requirements are made on the management of residues from industries processing naturally occurring radioactive materials (NORM) as well as on the monitoring of building materials. Although the BSS do not address specific monitoring issues, studies have been undertaken on effluents from hospitals and on long-term management of uranium mining areas. The proposal for the new Basic Safety Standards Directive is examined in the light of experience of the accident at Fukushima Dai-ichi Nuclear Power Plant disabled by the terrible tsunami on 11 March 2011. The arrangements for information exchange in a normal situation and in an emergency exposure situation need to be looked at from this perspective as well as from the perspective of smaller incidents such as the release of (131)I in Hungary in autumn 2011. Finally, an important novelty in the Euratom BSS is the inclusion of monitoring for the protection of non-human species in the environment, in line with ICRP Publications 103 and 108. These requirements are still under legal scrutiny in terms of the scope of the Euratom Treaty. The issue is very important also for the role of the Euratom legal framework in different EC policies, such as laid down in the Marine Waters Framework Directive or concluded under the OSPAR Convention (North-East Atlantic).

ASEBIR Quality Special Interest Group guidance for quality in assisted reproduction technology

Assisted human reproduction has undergone rapid advances since its inception 45 years ago. To keep pace with these advances, assisted reproduction laboratories should adhere to a quality management system that addresses staffing and training, physical space and air quality, equipment maintenance and other operational matters, and ensures gamete and embryo handling in accordance with the latest quality and safety standards. Accordingly, this review aims to provide a reference document that highlights the critical aspects to consider when establishing and operating an ART laboratory. The review collates and expands upon published national and international guidelines and consensus documents, providing easier access to this large body of important information.