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Identifying Possible Scenarios Where a Deep Learning Auto-Segmentation Model Could Fail
Published in Jinzhong Yang, Gregory C. Sharp, Mark J. Gooding, Auto-Segmentation for Radiation Oncology, 2021
The second type of scenario investigated was the potential effect of anatomical changes to the thorax produced by pre-existing conditions (atelectasis and pleural effusions) and patient immobilization technique, as well as the effect of the presence of contrast and implanted devices on the auto-segmentation. When considering atelectasis and pleural effusions, it was found that the accuracy of the auto-segmentations was greatly reduced when there was significant buildup of fluid in the pleura. Only a single case was located at MD Anderson Cancer Center where the abdominal compression immobilization technique was used during radiotherapy simulation; all organs at risk were accurately auto-segmented for this case but additional cases are needed to confirm that slight parameter differences in approach resolved the auto-segmentation errors previously reported by Feng et al. [2]. Lastly, the presence of contrast and high-density materials from medical implants was shown to have a negative impact on the quality of the auto-segmentations.
Cosmetic procedures
Published in Melanie Latham, Jean V. McHale, The Regulation of Cosmetic Procedures, 2020
Melanie Latham, Jean V. McHale
Concerns over medical devices regulation have been raised not only through the PIP scandal but more recently for example in relation to the controversy of the use of mesh in vaginal surgery.78 The UK Government in February 2019 admitted that there were problems in relation to the regulation of medical implants. In a parliamentary debate the Health and Care Minister Jackie Doyle-Price stated that It is fair to say that, perhaps in the past, regulation has focused excessively on what is in the commercial interests of businesses to maintain competition, rather than having patient safety at its heart.79 She also indicated that the government was also considering the establishment of a national medical devices registry. It was intended that this would mean that all implants would be traceable and in addition there would be alerts to regulators of problems where devices had been approved for clinical use. These proposals are to be welcomed. It is to be hoped that these are taken forward and in addition the inclusion of such information in a national registry is made compulsory.
Advanced Biotechnology
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
According to the U.S. Food & Drug Administration (USFDA), medical implants are devices or tissues that are placed inside or on the surface of the body. Many implants are prosthetics, intended to replace missing body parts. Other implants deliver medication, monitor body functions, or provide support to organs and tissues (FDA.gov).
Niosomal formulation for antibacterial applications
Published in Journal of Drug Targeting, 2022
Mehrnoush Mehrarya, Behnaz Gharehchelou, Samin Haghighi Poodeh, Elham Jamshidifar, Sara Karimifard, Bahareh Farasati Far, Iman Akbarzadeh, Alexander Seifalian
In previous studies, researchers developed new techniques for the surface treatment of medical implants; these are active and passive approaches. The passive approach is based on modifying the roughness and hydrophobic properties of the device surface; hence, the colonisation process of a surface of infecting bacteria is controlled by biomaterial surface attributes. However, the active approach relies on a combination of drug and medical device products. For instance, in this method, medical devices coating with antibiotics, antiseptics, etc [92–94]. As a result of these researches, the concept of implanting Nano-coating technologies was introduced. Recently, research in the realm of Nano-coated implants and ameliorating the surface of dental implants by applying niosome coated implants that are used as a drug carrier earned more attention. Additionally, niosomes have received great attention owing to their potential in offering a delivery system for lipophilic and hydrophilic drugs collectively. In addition, niosomes create adequate methodologies to manufacture drug delivery systems based on a lower antibiotic dose and are less susceptible to promote antibiotic resistance and prolonged sustained release for different drugs [2,14,95].
Structure and properties of a personalized bio-fixed implant prepared with selective laser melting
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Guoqing Zhang, Junxin Li, Jin Li, Xiaoyu Zhou, Anmin Wang
Biological performance and mechanical property requirements must be fully considered in the design of porous medical implants. Medical implants require the following biological properties (Karageorgiou and Kaplan 2005; Li 2008; Ning 2008; Huang et al. 2010; Xiao-Wei et al. 2014): (1) A pore range for osteocyte growth between 100 and 1000 µm. Pores less than 100 µm in diameter do not support the growth of capillaries or the passage of osteocytes. Pores greater than 1,000 µm in diameter will reduce the growth rate and physical volume of osteocytes. (2) High porosity. The degree of porosity affects cell ingrowth and cell migration, and affects the ability of growth factors and nutrients to enter materials. At high porosities between 50–90%, cancellous bone structure is simulated allowing new bones to grow. At higher porosity, the growth rate and volume of osteocytes increase, but the porosity range may be limited by mechanical requirements. (3) A large surface area to volume ratio. A large surface area to volume ratio of porous implants increases the contact between the surface of porous implants and bones and provides mechanical stimulation for new bones. The mechanical properties of medical implants should satisfy the following requirements (Spector et al. 1978; Xiao 2013): (1) Implants require sufficient compressive strength, stiffness, resistance to deformation, and damages after implantation. (2) The elasticity modulus of porous implants should be equivalent to that of the human skeleton and avoid “stress shielding”. (3) Implants should have good energy absorption properties for good shock resistance.
Microbial polyhydroxyalkanoates as medical implant biomaterials
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Strong mechanical properties and controllable biodegradability, together with biocompatibility, are important requirements for the development of medical implant materials. Ultraviolet (UV) radiation achieved controlled degradation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) which has a low biodegradation rate that limits its application for many implant applications required quick degradation. A broad PHBHHx Mw distribution was the result of inhomogeneous radiation, leading to strong mechanical properties of films made of the UV-radiated PHBHHx powder, while the PHBHHx films subjected to direct UV radiation became very brittle. Significant increases in growth of fibroblast L929 were observed on films prepared from UV-radiated powders. This improved cell growth could be attributed to increasing hydrophilic functional groups generated by increasing polar groups C–O and C = O [54].