Introduction: The Netherlands is experiencing a critical shortage of healthcare workers, particularly nurses. Operating rooms (ORs) face high turnover rates due to their unique and demanding environment. The introduction of Robot-Assisted Surgery (RAS) has added further complexity to the OR setting. While RAS offers benefits for patients and surgeons, its impact on the workload and job satisfaction of intra-operative nurses remains unclear. Given the link between workload and job satisfaction and nurse retention, it is essential to investigate how RAS affects the workload and job satisfaction of intra-operative nurses compared to laparoscopic and open procedures. This study aims to provide a nuanced understanding of these aspects and identify key influencing factors.

Method: A multi-method approach was employed among intra-operative nurses at Leids Universitair Medisch Centrum (LUMC), combining subjective data from questionnaires—including the Surgical Task Load Index (SURG-TLX)—with insights from semi-structured interviews. Additionally, objective data were analyzed from hospital records and video recordings. The study focused on the gynecology department, evaluating workload and job satisfaction across three main types of procedures: open, laparoscopic, and RAS. Variations in workload and job satisfaction during the pre-operative, intra-operative, and post-operative phases were also examined.

Results: The overall workload was deemed acceptable, with an average score of 34.58, below the detrimental threshold of 50. RAS procedures scored higher across multiple domains, resulting in a higher average workload score of 40.82, compared to 32.60 for open procedures and 30.32 for laparoscopic procedures. Open procedures were associated with greater job satisfaction than both laparoscopic and RAS procedures. Key factors affecting workload and job satisfaction included: team dynamics, procedural variation, preparation and equipment, working environment, appreciation and recognition, and physical demand. Interviews revealed that intra-operative nurses experienced more stress during RAS procedures, particularly in the preoperative phase, largely due to a lack of technological knowledge. Additionally, they felt less involved, and the working environment was perceived as less pleasant. Objective data from hospital records supported these findings, showing that RAS procedures typically had longer durations and more frequent overruns, often involving patients with lower acuity scores. This combination of reduced procedural complexity and extended surgery times contributed to a higher perceived workload and lower job satisfaction. The extended periods of dim lighting and the more crowded operating room further exacerbated the working environment’s discomfort, increasing the perceived workload and reducing job satisfaction. Video data analysis indicated less interaction with the operating table and reduced movement of personnel during RAS procedures, which potentially contributed to a diminished sense of activity and involvement, thereby increasing the perceived workload.

Conclusion: RAS procedures impose a greater workload on intra-operative nurses compared to open and laparoscopic procedures across multiple domains and result in less job satisfaction compared to open procedures. Data from questionnaires, interviews, hospital records, and video analysis consistently show a diminished sense of involvement and increased perceived workload during RAS procedures. This study underscores the need for improvements in preparation protocols, OR scheduling, intra-operative nurse involvement, and working conditions. These enhancements could help reduce perceived workload, increase job satisfaction, and ultimately address the growing nursing shortage in the Netherlands.

Background Over the past few years, virtual reality-based visual field assessments have been increasingly investigated. However, due to the limited field of view (FOV) that a virtual reality (VR) headset can offer, research to identify the visual field's outer limits has not been possible as the FOV falls short of the human visual field limits. This limitation has hindered the ability to accurately identify the outer limits of the visual field using VR technology. The Peili Research app, a VR-based kinetic perimeter, addresses this issue by employing off-centred focus points to expand the effective angle that can be tested.
Research Objective This research explores the feasibility of employing the Peili Research app, alongside the Pico Neo 2 Eye VR headset, as a bedside tool for visual field assessment.
Methods A series of analyses were conducted to evaluate the Peili Research app’s performance in visual field testing. The Spearman correlation matrix was used to assess test-retest reliability, and a comparison with Goldmann perimetry was made. The app’s design was evaluated by calculating the increase in effective testable angle through the off-centred focus point. In addition, the impact of observer differences due to human reaction time and the impact of stimulus colour contrast on the results was investigated. Data processing was conducted using a custom-developed MATLAB script to analyse the Peili data and determine the visual field angles in isopters.
Results Visual representations of the Peili Research app suggested a certain extent of test-retest reliability. However, Spearman correlations varied between poor and moderate. The application extends the testable visual field angle by 23 degrees on average. The study revealed that human reaction time in recording visual stimuli on the tablet led to an average underestimation of visual field angles by 5.38 degrees (p<0.001). Furthermore, colour contrast significantly affected detection angles, with green stimuli being detected at larger angles compared to blue and yellow stimuli (p<0.001). Clinical testing on postoperative volunteers highlighted practical challenges.
Conclusion The Peili Research app shows promise as a VR-based tool for visual field assessment, capable of expanding the testable visual field angle. However, variability in results, mainly due to the location of the focus points, reaction time, colour contrast, and the instability of the VR headset, highlights the need for further design refinements. Addressing these issues could enhance the app’s clinical applicability, making it a valuable tool for bedside visual field testing and improving patient outcomes.

Herniorrhaphy, the closure of an abdominal wall hernia, is one of the most performed general surgeries worldwide. However, approximately one-third of these patients require revision surgery due to hernia recurrence, possibly caused by excess tension on the aponeurotic edge. Currently, there is no standardized method to quantify this tension. This thesis aims to design a device for use in minimally invasive herniorrhaphy to provide intraoperative information on fascial tension to assist surgeons in intraoperative decision-making.
This thesis builds upon the work of E.F. van Koten, who designed an initial device called MINT based on a linear force spring to assess tension. However, her design was not yet suitable for intraoperative use due to small components and a high component count. Therefore, this thesis focuses on redesigning the MINT to reduce the complexity of the device.
Through the redesign of the connection mechanism, the component count was reduced from fourteen (and one tool) to five. This reduction has several advantages: it simplifies the device assembly and disassembly and reduces the risk of losing components. Consequently, the new design is more suitable for use in the operating room.
Further studies should investigate the reusability of the device made from selective laser sintered PA-12, and clinical testing is required before clinical implementation.

Introduction – Procedures related to cardiac catheterization are increasing, resulting in increased radiation exposure for medical staff and the associated health risks. To limit the amount of radiation exposure measures are used. In many cases those measures are not properly used due to the lack of awareness from the medical staff. The primary goal of this research is to integrate a radiation model with a tool, the Azure Kinect, to locate the medical staff and calculate the radiation exposure. The secondary goal is to track the lead shield resulting in the possibility to adjust to the optimal position for the staff while executing the surgery. This study may contribute to real-time dosimetry, the optimal position of both the medical staff and the lead shield, better awareness of radiation exposure, and generally a minimization of the exposure of the medical staff during procedures in the cath lab.
Method – The Azure Kinect DK is used to track the position of the medical staff and, with help of the Aruco markers the lead shield. By using an existing radiation model, the exposure of radiation can be calculated. Firstly, the accuracy of the tracking was ensured. Subsequently, the Azure Kinect’s ability was tested to capture difficult situations. Then, the applicability of the radiation model to the Azure Kinect measurements was tested. Finally, the ability to visualize changes and demonstrate their effect on radiation exposure was examined.
Results – The inaccuracy was higher than the Azure Kinect developers reported due to non-optimal conditions; the accuracy deviation had an absolute value of 6,25%. It was found that the deviation of the coordinates between the different measurement points are moderate, with a few outliers and the y-coordinates decreasing deviation as the cardiologist moves farther away from the phantom. By combining medical staff tracking software with the radiation model, radiation exposure can be calculated. The results show that the software detected a decrease in radiation exposure as the distance towards the source increased and the lead shield is placed closer to the cardiologist.
Discussion and Conclusion – This research aims to improve the awareness of radiation exposure in real-time during a procedure. This software represents a significant improvement over the equipment currently used, such as the Phillips Dose Aware badges and the Dosimetry badges.
Despite the error sensitivity of the Azure Kinect, the combination of the device and software can measure the radiation exposure of the medical staff in simulated procedural scenarios in the cath lab. However, there are some limitations resulting in not yet being applicable during a procedure.
Future research directions should enhance the system to increase the applicability during procedures. Optimization can be achieved by positioning of the Azure Kinect to reduce the change of possible occlusion during a procedure and tracking of the lead shield with the help of AI object detection.
By accomplishing these objectives, the gap can be narrowed between the use of this software in a test environment and its application during a procedure. Ultimately, this will lead to an increased awareness of unnecessary radiation exposure among medical staff during procedures.

Percutaneous coronary intervention (PCI) is one of the main medical procedures employed for the treatment of coronary artery disease. During this procedure, the coronary arteries are visualized using X-ray imaging. However, it only generates 2D images which can complicate several tasks, including assessing the lesion and correctly placing a stent. To overcome this limitation, researchers of Philips Research are developing technologies that allow the implementation of 3D imaging data derived from coronary CT angiography in the catheterization laboratory. Throughout the development, a coronary artery network phantom could serve as a beneficial tool. Such a phantom should be anthropomorphic and have realistic imaging and mechanical properties. Additionally, it should serve as a platform on which a basic PCI procedure can be performed. No commercially or academically developed phantom satisfies these criteria, thus the objective for this project was to design and develop an anthropomorphic coronary artery network phantom with realistic imaging and mechanical properties, which can be used to mimic both healthy and atherosclerotic human coronary arteries.
A material study was initially conducted to find the most suitable materials for the development of the phantom. During the first stage, the radiodensity of several materials was measured. Based on those results, and other factors such as safety, usability and durability, it was concluded that PlatSil Gel 25 would be used for the development of the arterial wall. Additionally, the heart and non-calcified lesions were to be made from VytaFlex 20 in combination with BaSO4. The calcified lesions were to be made from PlatSil Gel 25 and also required the addition of BaSO4 to increase their radiodensity. After the imaging tests, uniaxial tensile tests were conducted to measure the stiffness of PlatSil Gel 25 samples with different concentrations of PlatSil hardener. These results demonstrated that PlatSil Gel 25 has a comparable stiffness to that of healthy human coronary arteries in the longitudinal direction. When combined with the hardener, it can also mimic the stiffness of atherosclerotic coronary arteries.
After the material study, the coronary artery network phantom was designed and developed. The design comprises a simplified representation of the heart, and an arterial network that consists of the coronary artery network and a simplified representation of the arterial pathway distal to the aortic root. To manufacture the arterial network, a water-soluble 3D-printed mould was manually coated with PlatSil Gel 25 and subsequently dissolved in water. Due to the solubility of the mould, it was possible to manufacture a geometrically complex and hollow arterial network as a single part. Additionally, it was demonstrated that this manufacturing method can be used to include lesions within the arterial wall, and that its stiffness can be locally changed.
During the evaluation of the final phantom, its geometrical, imaging and mechanical properties were assessed and compared with the formulated requirements. Based on the results it can be concluded that the phantom meets many of the requirements. Furthermore, it was demonstrated that a guidewire can be inserted into the arterial network and manipulated up to the end of the left circumflex artery. Nevertheless, the evaluation also revealed some areas of improvement. Most notable are the improvements related to the imaging properties of the phantom. For example, the radiodensity of the arterial wall was slightly too high. In addition, the attenuation was not uniform throughout the parts of the phantom that contained BaSO4, as was evident from X-ray and CT images.
In conclusion, this project demonstrated that the utilized manufacturing method and materials can be used to develop a healthy and atherosclerotic coronary artery network phantom, that possesses realistic geometrical, imaging and mechanical properties. Additionally, it has the potential to serve as a platform on which a basic PCI procedure can be performed. Nevertheless, several areas of improvement related to both the manufacturing method and phantom remain, which might form the foundation for a future project.

The sentinel lymph node biopsy procedure for melanoma patients can be improved with the use of a minimally invasive sentinel lymph node biopsy device. This thesis shows the early stage designing process of such a device, which can reduce overall tissue damage and opens up possibilities to remove the need for general anaesthesia and therefore the need for an operating room. The design of a device that can locally expand a circular cutting blade is presented. The tests main conclusion is that three rods can indeed be used to actuate variable expansion of such a cutting blade. Subsequently, the blade can be used to cut around different sized target lymph nodes. Furthermore, actuation of this expansion can be achieved through a minimally invasive shaft from outside the patients body. Although further steps of the procedure need to be addressed in order to create a fully functional biopsy device, this thesis shows the potential and feasibility of a locally expanding adaptable cutting blade and provides recommendations for further development steps in the design of a MISLNBD.

Effective management of operating room (OR) schedules is vital for the efficient operation of healthcare facilities, especially considering the impact of decisions on staff, patients and costs. While extensive research has focused on optimizing initial schedules, the dynamic nature of surgery days introduces uncertainties that impact scheduling decisions. The study proposes equipping OR coordinators with a decision support system that leverages real-time insights and readily available hospital data to aid in decision making on the day of surgery. This thesis underscores the usefulness of OR policy documents in guiding decision support system design. Additionally, emphasis is placed on the need for standardized data and frequent real-time updates to improve the decision support systems accuracy and efficiency. To improve the performance of the decision support system efforts should be focussed on refining input data generated by hospitals.

INTRODUCTION Artificial intelligence (AI) has great potential to optimise patient care and reduce the bur- den on healthcare. Despite numerous AI solutions being developed for hospitals, the clinical adoption rate remains low, largely due to challenges in evaluating their practical usefulness before implementation. This research addresses the gap by developing a decision-making strategy that hospitals can use to assess whether specific AI applications should be implemented. The strategy aims to ensure that AI solutions are effec- tively integrated, address genuine problems, and meet stakeholder needs, thereby facilitating better decision- making and more successful AI adoption in clinical settings.
METHODS The methodology involved three key phases: development, testing, and evaluation of the decision- making strategy. The strategy was initially developed through an analysis of existing guidelines, specifically the "Stappenplan Healthy AI (HAI)" document, and corresponding literature. Stakeholder evaluations, in- cluding input from hospital AI teams, medical officers, and clinical specialists, were used to refine the strategy. A practical case study was conducted in the Radiology department of the Noordwest Ziekenhuisgroep (NWZ) hospital to test the strategy’s applicability, followed by stakeholder feedback through a structured question- naire to evaluate its effectiveness and usability.
RESULTS The results showed that the iterative development process, involving multiple rounds of stake- holder feedback, substantially improved the decision-making strategy’s comprehensiveness and relevance. Stakeholders highlighted that the strategy effectively captured critical aspects of AI integration, such as tech- nical requirements, stakeholder needs, and workflow implications. Testing in the Radiology department re- vealed challenges in identifying responsible individuals for data collection, which initially delayed the pro- cess, but also underscored the need for well-defined roles. The feedback from stakeholders was largely pos- itive, indicating that the strategy was clear and practical for evaluating AI solutions, though some improve- ments were suggested for addressing technical integration and detailing follow-up actions. Stakeholders ap- preciated the structured format, which facilitated effective communication and collaboration among differ- ent departments. Overall, the decision-making strategy succeeded in creating a robust framework for evalu- ating AI applications, helping ensure that such technologies are implemented thoughtfully and effectively.
CONCLUSION The aim of this study was to develop a decision-making strategy for hospitals to determine whether AI applications should be implemented, as well as to test and evaluate the strategy. The iterative process proved effective in creating a practical and efficient tool that helps identify potential bottlenecks and clarifies resource needs for implementation. The involvement of ICT stakeholders was crucial, highlighting the importance of technical evaluation as a key factor in decision-making. Overall, the strategy provides a focused and manageable framework that allows hospitals to evaluate AI applications effectively, supporting informed decisions to improve healthcare efficiency and patient care quality.

This thesis explores different ventilation systems used for operating rooms (OR). Entrainment test methods are used in most European standards to determine the protected zone whereas the air quality in the periphery is often excluded. Furthermore, these measurements are mostly carried out in an at-rest situation where intermittent sampling during operation should be required. Most ORs in the Netherlands have an air handling system with an ultra-clean ventilation system (UCV). ORs are energy-intensive departments, where air handling systems consume the most. Relatively simple adjustments can be made to the air handling system to reduce energy, such as expanding relative humidity limits and introducing operational clock times. Lowering outside air quantity has the biggest impact on energy reduction, lowering the OR classification the least. Reducing the air change rate in the OR from an ultra-clean to a generic OR will reduce the recovery degree and the local air change rate. Lowering the air change rate in operating rooms could harm comfort conditions and (ultra-clean) air quality. The capital and operational expenditures of air handling installations with an UCV-system are higher than those with a conventional system. The investment pays for itself when 2 to 4 surgical wound infections are prevented over the lifetime of the OR. The type of surgery should be a leading consideration in determining the typology of the air handling system and the type of air supply system. Absence of evidence that surgical site infections are prevented in ORs equipped with UCV-systems is not evidence that these are not prevented. @en

Purpose: In percutaneous renal ablation (PRA), reaching the target accurately is challenging due to target motion and limited real-time visualization of the target, requiring a suitable navigation strategy. In the context of this thesis research, skin markers are used in combination with an the Azurion C-arm system (Philips Healthcare, Best, The Netherlands), an image-guided therapy system, equipped with ClarifEye (Philips Healthcare, Best, The Netherlands), an Augmented Reality (AR) surgical navigation system. The skin markers are tracked by ClarifEye, virtually representing the position of the patient. This thesis aims to explore if skin markers can facilitate sufficiently accurate navigation in PRA by investigating the skin marker motion (SMM) and kidney tumor marker motion (TMM) during needle insertion, considering the insertion speed (IS) and level of perirenal fat (LPF). Methods: An ex-vivo porcine kidney model, with simulated skin, tumors and perirenal fat was developed and validated. A skin marker model was constructed on the model. Consequently, 60 robotic-assisted needle insertions were planned with ClarifEye (Philips Healthcare, Best, The Netherlands) navigation and performed on 8 kidney models (4 with low LPF (LLPF), 4 with high LPF (HLPF)), targeting 20 tumors at varying ISs: continuous insertions of 2.5 mm/s, 75 mm/s and consecutive 5 mm increments of 10 mm/s. Cone beam computed tomography (CBCT)-scans were made before and after insertion to analyze SMM and TMM. Results: The SMM (overall mean SMM = 0.16 mm, standard deviation (SD) = 0.14 mm) was smaller than the voxel-size (1D) of dViewX (dicom-viewer software, Philips Healthcare, Best, The Netherlands) (voxel-size 1D = 0.2425 mm), regardless of the direction of the SMM and regardless of the IS and LPF. The TMM values in the z-direction were predominantly negative. The IS and LPF did not impact the amount and direction of TMM.
Conclusion: Any local skin deformation caused by needle insertion resulted in negligible SMM. Although the skin markers do not account for the TMM caused by needle insertions, the median TMM values (1.2-1.9 mm) are still smaller than the minimally required clinical insertion accuracy of 3-5 mm. The acceptable TMM values, in combination with the negligible SMM values, imply that skin markers can be used to facilitate navigation in PRA.

Catheterization Laboratory (Cath Lab) is a hospital examination room equipped with diagnostic imaging equipment to display the heart arteries and to detect and treat any abnormality or stenosis. This thesis addresses the urgent need to improve the efficiency of operating rooms in Cath Labs due to the increasing number of patients with cardiovascular disease. Currently, measuring key performance indicators (KPI) for efficiency in Cath Labs requires manual observation and registration of patient entry and exit times, as well as the establishment and closure of access points. This process is time-consuming, costly, and prone to errors. To overcome these challenges, we conducted a study at the Reinier de Graaf Groep Hospital in Delft, where we recorded activities in the Cath Lab and developed a video-based event detection framework to automate the identification of these crucial events. The proposed framework consist of a fine-tuned YOLO v8 object detector, a popular object tracker ByteTrack, a post processing step and different event detection algorithms for different events of interest. This thesis presents the related video-based event detection framework and a detailed introduction for the development of object detector YOLO and object tracking technologies. The materials used in the project and how they work are clearly described. Events of interest are determined as needed for KPI calculations and are defined by describing the workflow in the target Cath lab. The steps taken to prepare the event dataset are also described in detail. The process of training, the connection between the tracker and the detector and the algorithms to detect different events for reproduction are explained. A series of performance tests on the target detector and tracker concluded that the tracker can handle the occlusion to some extent, but the performance of the object detector determined the performance of the tracker. It was also found that the simpler network structure in YOLOv8 outperformed the more complex network structure in detecting smaller objects on our dataset. In addition, the event detection algorithm is tested on multiple videos to evaluate its robustness and result showed that the algorithm can correctly and accurately detect the target events. The practical applicability of the framework and some future work that could enhance its performance are discussed. In conclusion, this thesis presents a video-based event detection framework that can detect events of interest in the Catheterization Lab at Delft Reinier de Graaf Groep Hospital.

Summary
Introduction
The increasing use of cardiac catheterisation procedures has raised concerns about occupational radiation exposure and its associated health risks for clinicians. Radiation exposure can lead to deterministic and stochastic effects, including cataract and various cancers. To minimise these risks, the ALARA (As Low As Reasonably Achievable) principle must be followed in the clinical setting by applying the available measures. Radiation protection consists of passive and active measures. Passive protection includes architectural shielding, stationary shielding, and personal protective equipment, while active protection focuses on minimising radiation during interventions, employing adjustable lead screens, modifying imaging techniques and provide feedback to improve the usage of these measures. However, current methods for measuring and providing feedback on radiation exposure are insufficient.
The primary goal of this research is to find a comprehensive and improved approach to guidance and implementation of protective measures, to ensure the safety and well-being of healthcare workers who face radiation exposure in their daily practice. An integral component of achieving this goal is to create a model that calculates radiation exposure for clinicians in the cathlab with the use of a lead screen. This research aims to determine the feasibility of using dose rate data from measurements without a lead screen to estimate the dose rate in an environment where a lead screen is employed. Moreover, potential methods for communicating dose rate data to clinicians during a procedure will be explored, aiming to increase their awareness of radiation exposure and encourage the adoption of appropriate protective measures without distracting them from the procedure itself.

Method
Data collection is necessary to construct a model that can predict the radiation scattering. Measurements in the catheterisation laboratory were performed by placing Philips DoseAware Detectors (PDDs) at various locations and heights. Combinations of fluoroscopy or acquisition mode, anteroposterior (AP) view or a 40° tilted view of the C- arm, and the presence or absence of a lead screen, resulted in eight different setups, with each 168 measurements.
In the programming process careful consideration has been given to the ease of refining and improving the model afterwards. Three potential source options for the radiation were considered: the centre of the phantom, a point where 50% of the scattering has occurred, and a 3D representation of the entire phantom. The modelled lead screen together with the source was used to create an attenuation grid, which will be used for the estimation of the effect of the lead screen.
The adequacy of the estimated dose rates with the lead screen was evaluated using boxplots and counting the number of correctly estimated points. Then, the data was interpolated using Kriging. The interpolated data was visualised, and the radiation doses for the assistant and cardiologist were calculated at the chest and head levels.
The exposure calculation was performed for three lead screen positions and a scenario without the lead screen. The placements considered were close to the clinician, close to the phantom, and at the edge of the phantom.
To explore radiation feedback preferences, a literature review and a questionnaire for interventional cardiologists were conducted.

Results
Measurements were taken for eight different setups, each with 168 measurements, including the combinations of fluoroscopy or acquisition mode, anteroposterior (AP) view or a 40° tilted view of the C-arm, and the presence or absence of a lead screen. The interpolated data revealed that the dose rate is higher when the acquisition mode is used, and radiation levels are higher when the C-arm is rotated. Three different source types were incorporated into the measurements, and the accuracy of the estimations was evaluated based on whether they were within a deviation of 0.1 mSv/h from the actual measurements. The 3D source was found to be the most accurate representation of the source in the model. Visualisation of inaccurately estimated values showed that the model overestimated the amount of radiation blocked in certain cases. The radiation exposure for clinicians increased as the lead shield was positioned closer to the radiation source.
A questionnaire was conducted with five interventional cardiologists to investigate their radiation safety practices. The results indicated that radiation safety is deemed important, with an average score of 8/10. The lead screen is an essential shielding component, but its placement varies, and there is uncertainty regarding its optimal positioning. Monthly reports on total radiation dose exposure were provided. The clinicians hardly paid attention to this information, as they believed that any potential harm had already occurred.
The highest-rated techniques were advice on optimal lead screen position (displayed on the lead screen) and a visualisation using augmented reality that displays the scatter pattern on the monitor.

Discussion and Conclusion
This study addresses radiation safety in interventional cardiology by exploring protective measures. A preliminary model was developed to predict radiation exposure based on the location of the lead screen enabling the computation of the radiation dose received by clinicians during a procedure. This dose rate model helps to visualise the impact of lead screen positioning on radiation exposure, which can aid in real-time decision-making during procedures. The model also revealed that placing the lead screen closer to the clinician, rather than closer to the source, could potentially enhance radiation attenuation by a factor of 6.2. This results in a possible dose reduction up to 32.5 times.
The most preferred option by the interventional cardiologists was to display the suggestion of the optimal position of the lead screen directly on the shield. A potential addition to the feedback system could be an augmented reality (AR) visualisation of the radiation effect on the monitor, clearly showing safe areas for personnel. The precise feedback mechanism should be piloted and refined to ensure seamless integration into clinical practice without distracting the clinician from the procedure itself.
Understanding the limitations of the measurements and the model is crucial for optimising its application in practice and the improve the reliability. The accuracy of measurements obtained with the DoseAware badges, while sufficient for this project, could be improved by using more accurate instruments. The phantom used in the study does not accurately represent real patients, and future research should involve patient- specific inputs and more realistic phantoms. One of the key future objectives include collecting more data in different settings and positions of the C-arm, as well as investigating different positions and orientations of the ceiling-mounted lead screen.
The model itself has limitations in its representation of the scattering source and interpolation methods. To improve the model, researchers should account for other sources of scatter, and assess alternative interpolation techniques using more powerful computing resources. Moreover, to calculate the received radiation dose, the model should consider the entire body, accounting for the protection provided by a lead apron and the concept of effective radiation dose.
Accomplishing these objectives will allow the model to play an important role in enhancing cathlab radiation safety, benefiting the health and safety of clinicians.

This thesis investigates clinical phase recognition for cardiac catheterization purposes, focusing on coronary angiography (CAG) procedures, in the context of an increasing annual prevalence of coronary artery disease. It applies machine learning to analyze C-arm logs and video recordings, aiming to improve procedural efficiency by recognizing procedural phases. Key findings include a baseline model with 45% accuracy; an 80.73% accurate C-arm model, including predictions only for operative phases; a 63.8% accurate object detection model, effective in initial and final phases but less so in operational stages; a combined data model with 79.46% accuracy, showing enhanced performance; and a reduced granularity model achieving 88.23% accuracy, highlighting a balance between granularity and performance. The combined model promises effective CAG phase recognition, especially with reduced granularity, offering comprehensive coverage and improved accuracy. However, it faces challenges in predicting specific phases accurately. The study recognizes limitations like the random forest model's non-temporal nature and potential information loss from object detection. Future research should expand datasets, explore temporal data models, and optimize the balance between granularity and performance for clinical applicability. In conclusion, the thesis contributes to SPR in cardiac catheterization labs, particularly in CAG, demonstrating the potential of machine learning models using C-arm and video data for phase recognition, which could enhance operational efficiency and patient care quality in cardiovascular interventions. Further research is needed to refine these models for clinical use.

Gastroschisis, a congenital abdominal wall defect located to the right of the intact umbilical cord (UC), results in the herniation of fetal abdominal organs into the amniotic cavity without a protective membrane covering these structures. Complex gastroschisis (CG), comprising approximately 10% of cases, is associated with significantly higher morbidity and mortality rates compared to simple gastroschisis. Fetoscopic repair of CG offers the potential to improve gastrointestinal health at birth, but thus far, no procedure has been successfully demonstrated as safe and feasible. Therefore, the goal of this graduation project was to provide a proof of principle for a novel dedicated method that enables the swift closure of the abdominal wall defect during a fetoscopic repair procedure for CG.

The development of this method began with an analysis of the clinical context, including the characteristics of the abdominal wall defect, the adjacent umbilical cord and vessels, and the fetoscopic surgical setup, which provided a clear design direction. After generating various concept solutions, the key concept — a silicone ring with membrane — was selected using the Harris Profile methodology. This concept was designed for insertion into the fetal abdominal cavity, with the membrane effectively covering the opening of the defect.

Eight configurations of the silicone ring with a membrane were then prototyped through injection molding of liquid silicone rubber in a 3D-printed mold. The rings varied in shape (round or rusk), diam- eter (20 mm and 30 mm), and stiffness (shore hardness A25 and A40). Additionally, a validation model simulating a 24-week-old fetus with CG was developed with input from medical experts.

The validation experiments demonstrated that the silicone ring with a membrane securely remained in place, effectively closing the abdominal wall defect under intra-abdominal pressure conditions ranging from 0 to 40 mmHg. These experiments, conducted using the validation model, simulated conditions during and immediately after fetal intervention in a 24-week-old fetus with CG following intestinal repositioning. These experiments provided proof of principle for the silicone ring with membrane as a novel method that enables the swift closure of the abdominal wall defect in CG during a fetoscopic repair procedure. Notably, round-shaped rings were favored, and larger diameters allowed for coverage of larger defects. However, it’s noteworthy that the 20 mm round ring effectively covered an oval-shaped defect measuring 13.5 × 12.7 mm, aligning with the reported mean defect size in CG. Furthermore, the experiments demonstrated the feasibility of introducing the rings through a 12 Fr (20 mm rings) or 14 Fr (30 mm rings) surgical port, aligning with the preferred surgical setup.

Future research is required to clinically investigate the defect diameter in CG and optimize the silicone ring with membrane’s design. Additionally, enhancing the validation model to serve dual purposes as both a validation and training model will facilitate user tests. Moreover, developing an instrument for introducing the ring into the uterus and refining the surgical technique for precise ring positioning will be essential steps toward the clinical application of this innovative approach.

The operating rooms (OR) in hospitals is a complex system, with a high number of innovations every year. Therefore the healthcare professionals (HCPs) are required to choose between the several aspects and innovations for the OR. Decision-making requires a mutual vision (Littlejohn et al., 2017) and should be based on evidence (Turner et al., 2017). To improve the well-informed decision-making, the main research question is: “How can a decision-support tool for optimisation in the operating room help a healthcare professional to select the objectives and the assessment criteria for performance optimisation of the operating room and the optimisation impact?”.

The evidence for the tool consists of the 223 relations between the objectives and the assessment criteria (metrics) and 253 causalities of metrics that express the impact. There is a high heterogeneous perspective on the objectives of the optimisation of the performance of the OR and the criteria of assessing the quantification of (the optimisation of) the OR performance, which makes it harder to create a mutual vision on the OR performance. To achieve a mutual vision, a holistic view and consider all the perspectives, including the impact of optimisations, the HCPs should all share their perspectives on the objectives and the situation should be considered in its whole (Leinonen et al., 2008; Littlejohn et al., 2017). Therefore, the decision-making process could benefit of a decision-support tool.

In this study a new tool is developed, namely the Performance Operating Room Counselling (PORC-)tool. This tool provides a holistic view of the OR performance (optimisation), by displaying evidence of the relations between objectives and metrics and the causalities. It also supports a conversation, which could lead to a mutual vision (Littlejohn et al., 2017). The tool is based on the concepts flowchart, matrix table and Microsoft Excel, for respectively the roadmap, the information display and the running-programme. The PORC-tool consists of an Excel file, a brochure and a manual with a more elaborated version of the functionality and the steps. The PORC-tool provides a clear and structural overview with evidence, to gather information more easily, provides multiple perspectives on the OR performance and supports to gather more insight into the OR organisation and goals before the decision-making of the HCP. The PORC-tool should be validated in practice and the functionality should be approved by HCPs. In the future, the tool can also be extended on perspectives, field of interest, aesthetics and functionality. To conclude, the answer to the main research question is that the HCPs should be facilitated to consider the whole complex system in their decision-making process, and support the decision-making based on evidence and with a mutual vision.

Surgical teams use instrument counts to prevent leaving unintended objects in patients. This is done manually, but could potentially be done through computer vision software. This paper presents a proof of concept for detecting instruments in the operating room with the Scale Invariant Feature Transform (SIFT). The SIFT algorithm is explored and tested on a variety of household appliances to substitute medical instruments. The algorithm responds differently to metal objects compared to matte objects and has room for many improvements. Further research on run time and multi object images is necessary. The proof of concept is considered successful when not taking run time into account.

Prostate cancer is the most frequently diagnosed cancer type among men, and the third deathliest form of cancer. Several treatments are available to treat prostate cancer. Low Dose Rate Brachytherapy (LDR BT) is one of them, which inserts permanent radioactive seeds into the prostate using a needle. The literature review performed prior to this thesis, investigates if LDR BT is an effective method and how the quality of life is affected by the treatment compared to other treatments. Furthermore, the various anatomical variations that could intervene with the procedure are analyzed and how they are currently dealt with. It was found that during this treatment multiple complications can arise; first pubic arch interference could prevent the needle from reaching all parts of the prostate. Second, unwanted needle deflection can cause incorrect dose distribution, and third, delicate tissues like the urethra can obstruct the path of the needle. The introduction of a steerable needle in the field of brachytherapy could have the potential of treating patients with particular anatomical variations, add more maneuverability for the surgeon to steer around certain tissues and adjust unwanted needle deflections. All contributing to an accurate dose distribution and therefore an improved quality of life of the patient.

This thesis aims to design and develop a steerable needle for LDR BT of the prostate along with defining the design parameters of the steering capabilities to predict the bending of the needle. The needle should have a lumen for radioactive seeds to pass through, should use the steering mechanism of the preceding high dose rate wire needle and it should be able to steer 30mm laterally over 150mm insertion in order to reach the entire prostate.

Multiple theories are developed to predict the deflection behaviour of the needle. A theory that can predict the needle tip path, two theories that predict the distal deflection in air, and lastly a theory that predicts the deflection in tissue. One of the theories that predict the distal deflection in air is based on the proximal angle and the other one on the proximal force. To test these theories, a steerable wire needle, made of spring steel, for high dose rate brachytherapy is borrowed. From these experiments it can be concluded that the theory for the prediction of the needle tip path gives results close to the measured values and the prediction of the distal deflection based on proximal force give adequate results with an error of 1.77mm ±1.6mm. This error is in between the acceptable threshold of 2mm-5mm. The other two models presented errors of 15.1mm ±15.2mm and 14.4mm ±14.6mm, which give inaccurate predictions and are therefore not used as basis for the design of the steerable needle. An analysis is performed on the individual parameters within the two models. This provides insight into which variables need to be adjusted to design a steerable needle that complies with the requirements.

Based on the two models and the analysis of the individual parameters, a steerable needle that complies with the requirements, is designed, manufactured and tested. The manufacturing of the needle was limited by the availability of materials, causing the inner lumen to be slightly smaller than initially designed. The first tests are performed in air to compare the results with the previous experiments done with the wire spring steel needle and to verify the prediction models. The needle tip path and distal deflection based on the proximal force predictions both proof to be adequate models with the latter having an error of 2.75mm ±2.99mm. The steerable nitinol needle with a lumen, is also tested in tissue stimulant to provide a proof of principle and verify the theory of deflection in tissue. It is demonstrated that the needle can steer within the tissue stimulant, and insert an object though its lumen into the tissue. The model for the prediction of the deflection in tissue can be proven empirically. In addition, the prediction of the distal deflection based on the proximal force can also be applied for bending in tissue, if a constant is added to account for the bevel tip of the needle.

To provide an additional substantiation for the prediction model, a third needle is tested in air. This needle is borrowed and is intended to be used in high dose rate brachytherapy. This needle, made of tungsten, also proofs that the model can make adequate predictions with an error of 1.76mm ±1.4mm.

One of the requirements of the needle is that the inner lumen must accommodate the passing of a radioactive seed. Due to the unavailability of certain materials this was not accomplished. Therefore, a theoretical design is made with a larger inner lumen. For further research this design can be manufactured and tested.

The steerable needle presented in this thesis provides a proof of principle for a steerable needle with a lumen. It could have the potential of overcoming the anatomical obstacles presented in the literature review and therefore aiding in an accurate dose distribution. Furthermore, it can also provide the surgeon with the capability of adjusting unwanted deflection created by the needle. In addition, by analyzing the variables that influence the steering, a model is made that can predict the deflection based on the proximal force applied.

This thesis concerns the design process of the mechanical excision mechanism of a minimally invasive sentinel lymph node biopsy medical device. The design is tested, validated and improved using force tests, data analyses, proof-of-principal tests, calculations and finite element method models. The conclusion of these analyses is that the mechanism works and that first promising steps towards realising a minimally invasive sentinel lymph node biopsy medical device have been taken.

The growing demand for cardiovascular treatments and the need to control the ever rising health care expenditures require efficient use of expensive resources, such as cardiac catheterization laboratories (cath labs). These in cardiac catheterization specialized operating rooms are labor and capital-intensive. Therefore, a high utilization is desired, although overtime should be prevented. However, this is complex in practice, because uncertainty in procedure duration and the number of patients makes it difficult to predict shift duration. At the moment, scheduling is mainly done by hand and the result strongly depends on the scheduler’s experience. Furthermore, little research is done on cath lab scheduling. Hence, this study aims to further define the cath lab scheduling process, identify the areas of improvement, and explore the usefulness of Monte Carlo simulation to support human schedulers. Schedulers of two Dutch hospitals, the Reinier de Graaf Gasthuis and the HagaZiekenhuis, are interviewed to map the scheduling process and identify the main difficulties. According to the schedulers, the main area of improvement is the estimation of procedure and shift duration, which currently is based on experience and rules of thumb. Based on the process in the HagaZiekenhuis, a Monte Carlo simulation is developed that computes the shift duration, utilization, and number of deferrals based on the blueprint schedule, the distributions of procedure duration and the emergency arrival rate. A first attempt to validate the model is done with input data from the VUmc as reported in another paper, as no historical data of the HagaZiekenhuis was available. The number of simulations required for convergence of the model was found to be at least 300. Next, the utilization, overtime, and undertime of the simulation were compared with these metrics from the VUmc. They were found to be close, even though the scheduling decisions are based on another hospital. To examine the sensitivity of the model, several scenarios are tested, namely, no emergency arrivals, a double amount of emergency arrivals, both halving and doubling the standard deviation of input distributions, adding extra patients to the inpatient waiting list to increase the demand, changing the threshold when patients are deferred and changing the type of input distribution from lognormal to normal. The effect of these scenarios is mainly as expected. Less variation in the output can be obtained by reducing the variance of the input distributions. Additionally, the type of input distribution seems to have limited effect on the output distribution. Furthermore, the effect of changing the deferral threshold, which is stochastic according to the interviews, seems limited. Moreover, no inexplicable behaviour was discovered by inspecting the realizations of the blue print schedule. Lastly, the data of the VUmc was applied to the blueprint of the HagaZiekenhuis, but inspection of the blueprint schedule revealed that the procedure duration in the VUmc data is longer than in the HagaZiekenhuis. This demonstrates that one cannot use the data and blueprint of different hospitals. An attempt was done to correct for this by scaling the distributions such that the mean corresponds to the scheduled duration. This led to more realistic results for some procedure types, although the standard procedure duration appears to not match the average duration for other types. The first results are promising, hence, a more in-depth validation of the model is recommended. The most promising application of this simulation seems the estimation of shift duration given a specific set of patients, integrated in the scheduling software.

Breast cancer is currently the most prevalent type of cancer. The concluding diagnosis can be obtained with an MRI-guided biopsy. However, due to respiratory movement and human error, the procedure can require multiple attempts, resulting in harmful consequences. To reach the target at the first attempt, the precision of the procedure should be increased, and a robotic system can aid in this. An MRI-compatible concept is designed, but two of its working principles need to be researched before further development.
A possible solution for increasing precision is rotating the needle along the insertion axis. Literature has studied the effect rotation has on insertion force, tissue indentation and target displacement in axial direction, which all show a decrease. However, the effect of rotation on the needle end-point position in lateral direction is not yet researched, and this is a good indication of targeting precision. Therefore, this work has studied the effect of rotation on the precision of the needle end-point position in lateral direction.
The concept uses pneumatically actuated stepper motors for the needle insertion. As the air will be supplied from outside the MRI room, the maximum frequency of air supply is estimated at 10 Hz. Therefore, the effect of an actuation frequency of 10 Hz on the precision of the needle end-point position in lateral direction is studied as well.
Both effects are researched by inserting a needle in a gelatin phantom at different angular velocities and at continuous versus discrete actuation. It is found that rotation significantly decreases the standard deviation in 6 of the 12 cases. The actuation frequency of 10 Hz does not significantly increase the standard deviation in 7 of the 8 cases. These results can be used to further increase the precision of a biopsy robot, whether it is for breast biopsy or another application.