Abstract Background: The benefit of MR-only workflow compared to current CT-based workflow for prostate radiotherapy is reduction of systematic errors in the radiotherapy chain by 2–3 mm. Nowadays, MRI is used for target delineation while CT is needed for position verification. In MR-only workflows, MRI based synthetic CT (sCT) replaces CT. Intraprostatic fiducial markers (FMs) are used as a surrogate for the position of the prostate improving targeting. However, FMs are not visible on sCT. Therefore, a semi-automatic method for burning-in FMs on sCT was developed. Accuracy of MR-only workflow using semi-automatically burned-in FMs was assessed and compared to CT/MR workflow. Methods: Thirty-one prostate cancer patients receiving radiotherapy, underwent an additional MR sequence (mDIXON) to create an sCT for MR-only workflow simulation. Three sources of accuracy in the CT/MR- and MR-only workflow were investigated. To compare image registrations for target delineation, the inter-observer error (IOE) of FM-based CT-to-MR image registrations and soft-tissue-based MR-to-MR image registrations were determined on twenty patients. Secondly, the inter-observer variation of the resulting FM positions was determined on twenty patients. Thirdly, on 26 patients CBCTs were retrospectively registered on sCT with burned-in FMs and compared to CT-CBCT registrations. Results: Image registration for target delineation shows a three times smaller IOE for MR-only workflow compared to CT/MR workflow. All observers agreed in correctly identifying all FMs for 18 out of 20 patients (90%). The IOE in CC direction of the center of mass (COM) position of the markers was within the CT slice thickness (2.5 mm), the IOE in AP and RL direction were below 1.0 mm and 1.5 mm, respectively. Registrations for IGRT position verification in MR-only workflow compared to CT/MR workflow were equivalent in RL-, CC- and AP-direction, except for a significant difference for random error in rotation. Conclusions: MR-only workflow using sCT with burned-in FMs is an improvement compared to the current CT/ MR workflow, with a three times smaller inter observer error in CT-MR registration and comparable CBCT registration results between CT and sCT reference scans. Trial registry Medical Research Involving Human Subjects Act (WMO) does apply to this study and was approved by the Medical Ethics review Committee of the Academic Medical Center. Registration number: NL65414.018.18. Date of registration: 21–08-2018.
LINK
Elke periode kent zijn eigen revolutie en elke revolutie brengt zijn eigen organisatorische model met zich mee. We bevinden ons nu in de 4e industri¨ele revolutie, waar het internet van dingen ons verbindt met autonome embedded systemen. Deze systemen zijn actief in de virtuele ’cyber’ wereld, alsook in de echte ’fysieke’ wereld om ons heen. Deze zogenoemde ’Cyber-Fysieke’ Systemen volgen daarmee een modern organisatorisch model, namelijk zelfmanagement, en zijn dan ook in staat zelf proactieve acties te ondernemen. Dit proefschrift belicht productiesystemen vanuit het Cyber-Fysieke perspectief. De productiesystemen zijn hier herconfigureerbaar, autonoom en zeer flexibel. Dit kan enkel worden bereikt door het ontwikkelen van nieuwe methodes en het toepassen van nieuwe technologie¨en die flexibiliteit verder bevorderen. Echter, effici¨entie is ook van belang, bijvoorbeeld door productassemblage zo flexibel te maken dat het daardoor kosteneffici¨ent is om de productie van diverse producten met een lage oplage, zogenaamde high-mix, low volume producten, te automatiseren. De mogelijkheid om zo flexibel te kunnen produceren moet bereikt worden door de creatie van nieuwe methoden en middelen, waarbij nieuwe technologie¨en worden gecombineerd; een belangrijk aspect hierbij is dat dit toepasbaar getest moet worden door gebruik van simulatoren en speciaal hiervoor ontwikkelde productiesystemen. Dit onderzoek zal beginnen met het introduceren van het concept achter de bijbehorende productiemethodologie, welke Grid Manufacturing is genoemd. Grid Manufacturing wordt uitgevoerd door autonome entiteiten (agenten) die zowel de productiesystemen zelf, als de producten representeren. Producten leven dan al in de virtuele cyber wereld voordat zij daadwerkelijk zijn gebouwd, en zijn zich bewust uit welke onderdelen zij gemaakt moeten worden. De producten communiceren en overleggen met de autonome herconfigureerbare productiesystemen, de zogenaamde equiplets. Deze equiplets leveren generieke diensten aan een grote diversiteit aan producten, die hierdoor op elk moment geproduceerd kunnen worden. Het onderzoek focust hierbij specifiek op de equiplets en de technische uitdagingen om dynamisch geautomatiseerde productie mogelijk te maken. Om Grid Manufacturing mogelijk te maken is er een set van technologische uitdagingen onderzocht. De achtergrond, onderzoeksaanpak en concepten zijn dan ook de eerste drie inleidende hoofdstukken. Daarna begint het onderzoek met Hoofdstuk 4 Object Awareness. Dit hoofdstuk beschrijft een dynamische manier waarop informatie uit verschillende autonome systemen gecombineerd wordt om objecten te herkennen, lokaliseren en daarmee te kunnen manipuleren. Hoofdstuk 5 Herconfiguratie beschrijft hoe producten communiceren met de equiplets en welke achterliggende systemen ervoor zorgen dat, ondanks | Dutch Summary 232 dat het product niet bekend is met de hardware van de equiplet, deze toch in staat is acties uit te voeren. Tevens beschrijft het hoofdstuk hoe de equiplets omgaan met verschillende hardwareconfiguraties en ondanks de aanpassingen zichzelf toch kunnen besturen. De equiplet kan dan ook aangepast worden zonder dat deze opnieuw geprogrammeerd hoeft te worden. In Hoofdstuk 6 Architectuur wordt vervolgens dieper ingegaan op de bovenliggende architectuur van de equiplets. Hier worden prestaties gecombineerd met flexibiliteit, waarvoor een hybride architectuur is ontwikkeld die het grid van equiplets controleert door het gebruik van twee platformen: Multi-Agent System (MAS) en Robot Operating System (ROS). Nadat de architectuur is vastgesteld, wordt er in Hoofdstuk 7 onderzocht hoe deze veilig ingezet kan worden. Hierbij wordt een controlesysteem ingevoerd dat het systeemgedrag bepaalt, waarmee het gedrag van de equiplets transparant wordt gemaakt. Tevens zal een simulatie met input van de sensoren uit de fysieke wereld ’live’ controleren of alle bewegingen veilig uitgevoerd kunnen worden. Nadat de basisfunctionaliteit van het Grid nu compleet is, wordt in Hoofdstuk 8 Validatie en Utilisatie gekeken naar hoe Grid Manufacturing gebruikt kan worden en welke nieuwe mogelijkheden deze kan opleveren. Zo wordt er besproken hoe zowel een hi¨erarchische als een heterarchische aanpak, waar alle systemen gelijk zijn, gebruikt kan worden. Daarnaast laat het hoofdstuk o.a. aan de hand van enkele voorbeelden en simulaties zien welke effecten herconfiguratie kan hebben, en welke voordelen deze aanpak zoal kan bieden.. Het proefschrift laat zien hoe met technische middelen geautomatiseerde flexibiliteit mogelijk wordt gemaakt. Hoewel het gehele concept nog volwassen zal moeten worden, worden er enkele aspecten getoond die op de korte termijn toepasbaar zijn in de industrie. Enkele voorbeelden hiervan zijn: (1) het combineren van gegevens uit diverse (autonome) bronnen voor 6D-lokalisatie; (2) een data-gedreven systeem, de zogeheten hardware-abstractielaag, die herconfigureerbare systemen controleert en de mogelijkheid biedt om deze productiesystemen aan te passen zonder deze te hoeven herprogrammeren; en (3) het gebruik van Cyber-Fysieke systemen om de veiligheid te verhogen.
MULTIFILE
In this study we measured the performance times on the Wheelchair Mobility Performance (WMP) test during different test conditions to see if the performance times changed when wheelchair settings were changed. The overall performance time on the WMP test increased when the tire pressure was reduced and also when extra mass was attached to the wheelchair. It can be concluded that the WMP test is sensitive to changes in wheelchair settings. It is recommended to use this field-based test in further research to investigate the effect of wheelchair settings on mobility performance time. Objective: The Wheelchair Mobility Performance (WMP) test is a reliable and valid measure to assess mobility performance in wheelchair basketball. The aim of this study was to examine the sensitivity to change of the WMP test by manipulating wheelchair configurations. Methods: Sixteen wheelchair basketball players performed the WMP test 3 times in their own wheelchair: (i) without adjustments (“control condition”); (ii) with 10 kg additional mass (“weighted condition”); and (iii) with 50% reduced tyre pressure (“tyre condition”). The outcome measure was time (s). If paired t-tests were significant (p < 0.05) and differences between conditions were larger than the standard error of measurement, the effect sizes (ES) were used to evaluate the sensitivity to change. ES values ≥0.2 were regarded as sensitive to change. Results: The overall performance times for the manipulations were significantly higher than the control condition, with mean differences of 4.40 s (weight – control, ES = 0.44) and 2.81 s (tyre – control, ES = 0.27). The overall performance time on the WMP test was judged as sensitive to change. For 8 of the 15 separate tasks on the WMP test, the tasks were judged as sensitive to change for at least one of the manipulations. Conclusion: The WMP test can detect change in mobility performance when wheelchair configurations are manipulated. https://www.medicaljournals.se/jrm/content/html/10.2340/16501977-2341
MULTIFILE
The anterior cruciate ligament (ACL) is a strong rope-like tissue which connects the femur to the tibia in the knee joint. Its function is to provide structural stability to the knee while preventing unnatural forward movement of the tibia relative to the femur. Acute complete ACL ruptures during movements like knee hyperextension or sudden changes of direction (pivoting) damage two entities: the ligament itself and its nerve connections to the posterior tibial nerve (PTN). PTN innervation in the ACL is essential for: a) proprioception (e.g. perception of position and movement/acceleration experienced by the ligament), and b) stability of the knee joint. Upon ACL rupture, the orthopedic surgeon reconstructs the ACL with a graft from the hamstring, patellar or quadriceps tendon. After the surgery, the goal is to regain neuromuscular control and dynamic stabilization during rehabilitation as soon as possible for a quick return to sports and daily activities. However, surgeons are not able to reconstruct the nerve gap between the PTN and the grafted ligament due to the microscopic size of the innervation in the ACL. Not linking the PTN to the graft creates a disconnection between the knee joint and the spinal cord. To mitigate these disadvantages in ACL surgery, this study focuses on activating the growth of proprioception nerve endings using a ligament loaded with growth factors (neurotrophins). We hypothesize that neurotrophins will activate proprioceptive fibers of neurons close to the ACL. We describe graft fabrication steps and in vitro experiments to expand on the regeneration capacity of a commercially available ACL-like synthetic ligament called LARS. The results will bring the ACL regeneration field closer to having a graft that can aid patients in regaining mobility and stability during locomotion and running, confidence in the strength of the knee joint, and quick return to sports.
The textile and clothing sector belongs to the world’s biggest economic activities. Producing textiles is highly energy-, water- and chemical-intensive and consequently the textile industry has a strong impact on environment and is regarded as the second greatest polluter of clean water. The European textile industry has taken significant steps taken in developing sustainable manufacturing processes and materials for example in water treatment and the development of biobased and recycled fibres. However, the large amount of harmful and toxic chemicals necessary, especially the synthetic colourants, i.e. the pigments and dyes used to colour the textile fibres and fabrics remains a serious concern. The limited range of alternative natural colourants that is available often fail the desired intensity and light stability and also are not provided at the affordable cost . The industrial partners and the branch organisations Modint and Contactgroep Textiel are actively searching for sustainable alternatives and have approached Avans to assist in the development of the colourants which led to the project Beauti-Fully Biobased Fibres project proposal. The objective of the Beauti-Fully Biobased Fibres project is to develop sustainable, renewable colourants with improved light fastness and colour intensity for colouration of (biobased) man-made textile fibres Avans University of Applied Science, Zuyd University of Applied Sciences, Wageningen University & Research, Maastricht University and representatives from the textile industry will actively collaborate in the project. Specific approaches have been identified which build on knowledge developed by the knowledge partners in earlier projects. These will now be used for designing sustainable, renewable colourants with the improved quality aspects of light fastness and intensity as required in the textile industry. The selected approaches include refining natural extracts, encapsulation and novel chemical modification of nano-particle surfaces with chromophores.
In greenhouse horticulture harvesting is a major bottleneck. Using robots for automatic reaping can reduce human workload and increase efficiency. Currently, ‘rigid body’ robotic grippers are used for automated reaping of tomatoes, sweet peppers, etc. However, this kind of robotic grasping and manipulation technique cannot be used for harvesting soft fruit and vegetables as it will cause damage to the crop. Thus, a ‘soft gripper’ needs to be developed. Nature is a source of inspiration for temporary adhesion systems, as many species, e.g., frogs and snails, are able to grip a stem or leave, even upside down, with firm adhesion without leaving any damage. Furthermore, larger animals have paws that are made of highly deformable and soft material with adjustable grip size and place holders. Since many animals solved similar problems of adhesion, friction, contact surface and pinch force, we will use biomimetics for the design and realization of the soft gripper. With this interdisciplinary field of research we aim to model and develop functionality by mimicking biological forms and processes and translating them to the synthesis of materials, synthetic systems or machines. Preliminary interviews with tech companies showed that also in other fields such as manufacturing and medical instruments, adjustable soft and smart grippers will be a huge opportunity in automation, allowing the handling of fragile objects.
