This study explores the impact of different bicycle saddle designs on saddle pressure distribution and comfort in female cyclists suffering from medical conditions affecting the groin area, including Lichen Sclerosus, Lichen Planus, and Vulvar Carcinoma. These conditions can cause discomfort and pain during cycling, leading to a decrease in physical activity and quality of life. The research involved a comparison of four distinct saddle designs, each aimed at reducing pressure in specific areas through partial cutouts or surface depressions. Participants were divided into a case group, comprising 23 women with the aforementioned medical conditions, and a control group of 50 women with no such conditions. Pressure measurements were collected using a stationary bicycle and a pressure mapping saddle cover containing 64 sensors. Additionally, participants completed questionnaires to evaluate perceived comfort and symptom severity. The quality of life (QoL) score was significantly lower in the case group (0.83 ± 0.09) compared to the control group (0.96 ± 0.09, p < 0.001). No significant differences were found between the case and control group in terms of cycling habits. Complaints during cycling were reported by 100% of the participants in the case group and only 8% of the participants in the control group. Pain and numbness were the most reported symptoms for cycling at home. The results indicated significant differences in loaded weight per saddle between the case and control groups (p = 0.001, p = 0.010, p = 0.003 & p = 0.013). In the case group, participants experienced higher pressure. Saddle 2 was favored by 44% of the case group participants for home testing. These findings underscore the need for specialized saddle designs to improve cycling comfort and potentially alleviate pain for women with medical conditions in the groin area.

Surgical aerosols in other words plumes are produced during thermal tissue destruction in medical operations. The cellular debris in the form of particulate matter may contain viruses and harmful chemical compounds which can lead to an infectious transmission in case of inhalation.
The goal of this study was to design and produce an experimental setup to simulate Plasmajet (PJ) and ERBE experiments with minimal airflow disturbances. Such setup can lead to defining the lowest aerosol production conditions, investigating the production-affecting factors, and evaluating tissue effects to promote a safer and healthier surgical environment for both healthcare workers and patients. A clear correlation between the aerosol production affecting factors and particle counts was established for particle sizes 0.3, 0.5, 1.0, 2.0, 5.0, and 10.0 µm.
The results of the experiments showed that among all experimental conditions, the PJ coagulation mode with fast operation yielded the lowest aerosol counts. In cutting mode, the lowest aerosol counts were also produced by PJ with fast operation speed. However, between speed and aerosol counts, no statistically significant correlation was found.
Upon analyzing the correlation between aerosol counts and tissue effects, it was determined that, for ERBE device, higher aerosol counts were associated with darker tissue effects. In the case of the PJ device, this relationship persisted in the cutting mode, whereas no connection between tissue effect and particle counts was observed in the coagulation mode.
Further investigation on the toxicity of the produced particulate matter and establishment of a clear minimal aerosol intake is recommended. Until then, preventive measures such as implementing local exhaust ventilation and using surgical N95 masks are strongly advised to minimize aerosol inhalation.

Vulvar cancer has significant implications for women's health and quality of life, emphasizing the need for prompt diagnosis and treatment. Surgical treatment aims to remove both visible and nonvisible malignant cells, incorporating a safety margin beyond the tumour perimeter. However, accurately assessing cancer spread and determining the optimal safety margin size remains challenging. Hyperspectral imaging allows non-invasive identification of vulvar tumour boundaries, capturing both spatial and spectral details of the region of interest. However, tissue type classification in hyperspectral imaging is complex due to the abundance of wavebands and limited training samples. Artificial intelligence (AI) methods show promise for accurate and automated tumour classification in hyperspectral imaging. In this study, four AI models (Support Vector Mechanism, Neural Network, 1D and 3D Convolutional Neural Networks) were trained to classify tumour tissue, skin tissue, and mucosa tissue. Additionally, the study aimed to explore the use of specific explanatory parameters (Tissue Water Index, Near Infrared Perfusion Index, and Tissue Haemoglobin Index) to reduce the spectral dimension, potentially improving acquisition time and interpretability without compromising classification accuracy. The study included 25 patients (mean age 71), with hyperspectral cubes captured from each patient. All cubes contained healthy skin tissue, while 22 cubes included tumour tissue and 10 cubes contained mucosa tissue. All models exhibited comparable performance for tumour detection, with F1 scores ranging between 0.91 and 0.93 and AUC-ROC scores ranging between 0.91 and 0.94. Moreover, the Neural Network trained only on the explanatory parameters achieved excellent results for tumour detection with an F1 score of 0.93 and AUC-ROC of 0.91. Overall, combining hyperspectral imaging with all models shows great potential for in vivo tumour detection, while leveraging physiological explanatory parameters with a Neural Network model can enhance acquisition time and data interpretability without compromising the classification accuracy.

Introduction: The Erasmus MC and TU Delft started the ARCHITECT project to develop a personalized applicator design approach for performing brachytherapy in patients with cervical cancer.
Workflow for executing brachytherapy differs a lot between institutions.
An overview of the workflow was created and time analysis of the steps was performed to identify bottlenecks and points of improvement in the current clinical practice of brachytherapy in cervical cancer. This overview could also be used as a reference for future research.
Methods: An overview of the workflow was created, the time needed for the different steps was registered and patients were asked to fill out questionnaires on patient experience. The current clinical practice was observed to create the workflow overview and define the steps of which time should be registered. As some steps occurred in parallel the radiotherapy technicians, radiation oncologists and nurses were asked to assist in reporting of times. Matlab was used to calculate the duration of the steps and SPSS was used to determine the descriptive statistics.
The research protocol written for the patient experience study was approved but the medical ethics committee. Patients were informed on the study so they could provide informed consent.
The EQ-5D questionnaire was used to asses initial pain, anxiety and quality of life. A questionnaire on pain, anxiety and duration of each step during treatment day that was used for evaluating patient experience.
Result: A workflow overview per location was created. Data of forty implantations in fifteen patients were included for time analysis. The general steps and mean time needed for these steps were: operating room (55 minutes), waiting before arrival at imaging (80 minutes), applicator reconstruction (57 minutes), contouring (50 minutes), treatment planning (50 minutes), clinical physicist check (22 minutes) and treatment room (41 minutes). The mean total procedure time from patient entering the operating room until leaving the treatment room was 391 minutes.
The time needed for implantation of subsequent treatment fractions compared to the first treatment fraction decreased in sixteen out of the twenty fractions. The time needed at the operating room in patients receiving spinal anesthesia did not differ from patients receiving general anesthesia.
Four patients provided informed consent and filled out the questionnaires on patient experience. Patient experience differed a lot in these four patients. Overall, highest anxiety scores were found during the first brachytherapy day and highest pain scores were found during the waiting time at the short stay unit.
Discussion: The steps observed in the Erasmus MC did not agree on all steps that were found in literature. Time needed for these steps also differed when comparing to literature. The total waiting time could be decreased when enabling a more smooth transition between the recovery room and imaging step.
Adaptions to the time registration sheet should include the time needed for assembling the applicator at the operating room. The contouring step should be separated in contouring of the OAR and target volume. Time needed for imaging is not that important as the imaging protocol is the same in all patients. The decrease in waiting time for imaging when using the hyperthermia MRI should be evaluated. The influence of the amount of patients treated during one day would also be interesting to evaluate when more data has been collected. Another interesting factor would be differences in duration of the steps and pain experienced in patients treated with the Venezia applicator compared to the Utrecht applicator. More patients need to be included in the questionnaire study to draw conclusions on patient experience.

Brachytherapy (BT) is an essential component in the treatment of cervical cancer as it allows for locally delivering a high dose to the tumour with minimal trauma to surrounding tissues and organs at risk (OARs). However, in advanced cervical cancer patients commercially available BT applicators are particularly ill-adapted and therefore result in suboptimal local control and frequent occurrence of substantial tissue morbidity. Additionally, cervical cancer BT is associated with large dosimetric uncertainty which has been shown to significantly impact the delivered dose and the occurrence of normal tissue complications. The clinical outcomes of treatment may be improved through combined efforts in sophisticated applicator design and robust treatment optimisation. Patient-tailored BT applicators have been introduced to improve dose conformity, but currently rely on manual indication of needle channels. Automated needle channel planning software exists, but does not account for OAR dose constraints or uncertainty in planning. Robust treatment optimisation potentially improves the dose conformity of plans in the presence of uncertainty, but relies on the questionable presumption that optimisation of dwell times can fully correct for suboptimal dwell positions. In this thesis, the freedom of source placement that 3D-printed applicators allow and the principle of robust treatment optimisation are leveraged to develop robust needle channel planning software for personalised applicators. This thesis was accordingly divided into three parts. In the first part, literature was reviewed to establish the dosimetric uncertainty budget and evaluate geometric uncertainty of OARs. Inter and intra-fraction uncertainty are likely the greatest contributors to the uncertainty budget, possibly increasing the delivered dose to OARs with up to 4.0±20% (k = 1). Using dose-response models it was established that this may realistically increase the occurrence of moderate to severe morbidity of the bladder or rectum by 1.5 and 3.7% respectively. The BT needle channel planning problem under uncertainty was accordingly defined as the problem of computing multiple feasible, non-intersecting curvature- constrained channels under probabilistic or bounded spatial uncertainty of OARs. In the second part, a tool termed motion-planning quality function deployment (MP-QFD) was developed to select a suitable motion planning class. Using the results from a pilot study among nine medical specialists, this tool substantiated the preferred choice for an incremental sampling-based motion planning algorithm. In the last part, robust variants of sampling-based planners were introduced that are capable of computing trajectories for non-holonomic agents in environments under uncertainty. In a two-dimensional simulated patient case, it was shown that these planners were able to generate near-optimal trajectories that (probabilistically) guaranteed not exceeding OAR dose constraints. Subsequent dose-based optimisation showed that (robust) trajectory planning could theoretically yield treatment plans with improved dose conformity over those generated for conventional applicators. Due to modelling assumptions, robust motion planning did not result in improved dose conformity over a nominal motion planning approach in a worst-case scenario. Future work should therefore focus on improving our understanding of OAR movement in and during BT treatment and validating this theoretical work in a patient case series.

BACKGROUND: Ovarian cancer is the number eight cause of cancer-related mortality in women around the world and has an incidence of more than 295 000 and mortality of almost 158 000. The most important prognostic factor for the survival of advanced-stage ovarian cancer is the complete resection of all microscopic tumour tissue during cytoreductive surgery. Still, even after complete CRS and removal of all visible and palpable tumours, more than two-thirds of women with advanced-stage ovarian cancer experience recurrence due to microscopic residual tumour. Therefore, an intraoperative visualisation technique is of great importance to detect these microscopic tumours. In this pilot study, the feasibility of NIR hyperspectral imaging for the detection of malignant ovarian cancer metastases was evaluated ex vivo. METHOD: Patients with suspected primary ovarian cancer planned for cytoreductive surgery were enrolled in the study. Hyperspectral images from the resected tissue were acquired in the wavelength range of 665-975 nm. All hyperspectral data was preprocessed by image calibration, min-max normalisation and noise filtering. The the most important features were selected before implementing the hyperspectral data in the classifier. The linear SVM, RBF SVM, and a k-NN classifier were used to discriminate malignant ovarian tissue from the surrounding tissue. The performance of the classifier was evaluated by leave-one-out cross-validation. RESULTS: Ten patients were included in the study. The linear SVM classifiers had the highest performance with a sensitivity of 0.81, a specificity of 0.75, AUC of 0.83 and MCC of 0.41. Thereafter came the RBF SVM classifier followed by the k-NN classifier. CONCLUSION: This pilot study shows that hyperspectral imaging with the use of a linear SVM classifier is a promising technique to discriminate malignant ovarian tissue from the surrounding tissue. Hyperspectral imaging can scan a whole area, is fast, non-contact, non-invasive and can be used inside the operation room. However, before HSI can be implemented in real practice, further validation is required in vivo and technical enhancements need to be made such as enlarging the training data set, evaluate the SWIR wavelength range, include a registration algorithm which accounts for elastic deformation of the tissue, evaluate several feature selection methods, and compare other classifiers.

PURPOSE. The purpose of this thesis is to investigate the possibility of implementing a prototype of a steerable needle in a medical procedure. Therefore the two main research questions are: “Can the intended user perform a steering motion with the steerable needle and reach the target area following a straight and curved trajectory?” and “Does the tip of the cannula maintain its position after the instrument change with a biopsy needle for a straight and curved trajectory?”.
METHODS. Two studies were conducted to answer these research questions. A user study was designed and performed to test the steering properties of the steerable needle for a straight and curved trajectory. A second controlled study with automated insertions was designed and performed to investigate the cannula tip displacement after the instrument change.
RESULTS. The results of both studies show that steering towards a specific target is highly achievable with the steerable needle for insertions with a straight and curved trajectory. Results also show a high success-rate, a low time consumption for the instrument change, and a high satisfactory level on the manual handling of the steerable needle by the interventional radiologists. The results of the second study show that the cannula tip maintains its position after the instrument change for a straight trajectory, and the cannula tip only displaces 1.4 mm back over a deflection of ±25 mm after the instrument change for a curved trajectory.
CONCLUSION. Reaching the target with a steering motion is achievable with the steerable needle and only a small displacement of the cannula tip is seen after the instrument change for a maximum imposed curved trajectory. These results answer the main questions concerning the effectivity of the steerable needle and are promising for future implementation of this prototype in a real medical procedure, containing real patients, and real liver tissue.
KEY WORDS. liver disease – liver biopsy – radiofrequency ablation – steerable needle – polyvinyl alcohol

In recent years, more and more medical operations are done minimally invasive. Intervention radiology is a medical specialty which uses minimally invasive techniques to diagnose, or treat diseases. Instruments like needles and catheters are used by radiologists to enter the network of veins and arteries guided by image modalities. A complex treatment in the interventional radiology is the Transjugular Intrahepatic Portosystemic Shunt (TIPS) procedure. This treatment is developed for people who suffer from liver cirrhosis which are not eligible for liver transplantation. The problem which arise with a liver affected by cirrhosis is that it can not transmit enough blood. Without transplantation or a treatment this will eventually lead to death. During the TIPS procedure a connection is made between the right hepatic and the portal vein by a shunt. As a result, blood pressure reduction in the portal system since the blood can flow back to the right atrium of the heart, bypassing the liver.

The hardest part in a TIPS procedure is the intrahepatic puncture between the hepatic and portal vein. The interventional radiologist tries to enter the portal vein by puncturing a small stylet from the hepatic vein through the liver tissue. Due to cirrhosis the liver tissue is very stiff and stylet deflection will occur. To reduce the uncertainty of entering the portal vein, this thesis is focused on designing a stylet that is more stiff and able to steer. It is expected that the complexity of the procedure will be reduced and a higher hit rate to enter the portal vein will be achieved.\\
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The prototype of the steerable stylet has been evaluated through various experiments, a visibility test and with procedures in a test liver model. During these experiments the steering characteristics, the stiffness of the stylet, the maximum lateral forces exerted by the tip while steering, the influence of the stylet orientation and the visibility are obtained. Afterwards, an evaluation was done in a liver model, made of PVA, to determine whether the stylet is capable to reduce the complexity of the intrahepatic puncture step in the TIPS procedure.

With the prototype made in this graduation project, based on a steerable ablation needle, the complexity of the TIPS procedure is not reduced yet. The steerable stylet was not able to enter the portal vein. It was already hard to enter the right hepatic vein since the pre-bent stiffening cannula was adapted with a smaller angle which was necessary since the steerable stylet was too stiff to push through the pre-bent angle. According to this prototype, possibilities are shown to use a mechanical steering mechanism in instruments with a long thin shaft. The transmission in combination with the joint mechanisms fits within 1.3mm diameter, was able to bridge 60cm from distal end to proximal end and had only 4 components, the stylet, the rigid cannula, the key to fix the stylet to the rigid cannula and the transmission. By translating the stylet in a push or pull direction relative to the rigid cannula, steering angles could be achieved. With further research and development this steering mechanism must be able to steer the required amount of degrees without any extra components, is well visible with ultrasound, and is good resistant against lateral forces.

Brachytherapy is recommended in the treatment of cervical cancer. In case of a tumour extending lateral to the pelvic wall or more than 0.5 cm from the vaginal surface, current applicators are not sufficient to irradiate the target area. Therefore, the use of extra free-hand needles is required. Free-hand placement of interstitial needles is operator/experience dependent. The goal of this study is to develop a device that is able to irradiate the tumour in case of lower vaginal involvement or distal parametrial extension. Based on the design criteria, a new concept has been developed. The concept is a personalised 3D-printed vaginal template with curved channels based on the MRI scan from the patient. Channel curvature constraints were examined by conducting an experiment with a separate 3D-printed template. The effects of two different needle tips (round and sharp) and 12 different curvatures (radius = 20 - 75 mm, with increments of 5 mm) on the required insertion force have been examined. A 3D-printed template with different curvatures has been suspended in a 10 m\% gelatin phantom. Needles were inserted with an obturator at a speed of 5 mm/s, using a linear stage. Axial forces were measured. The data was processed and compared with a subjective user experiment of manual insertions. To examine technical feasibility of the concept, two relevant cases of cancer were used to create personalised applicators. The accuracy of the needle tip placement with these templates has been tested. No differences have been found in maximum required insertion force for a round and sharp needle tip while passing through a template with different curvatures and while puncturing tissue. For the different curvatures, significant differences in axial force have been found for curvatures with radii $\leq$ 50 mm. Buckling behaviour occurred for radii $\leq$ 35 mm. The user experiment indicates a threshold value of 35 mm for the minimum radius for a round and sharp needle that is still comfortable to insert. Two relevant cases of vaginal cancer were successfully translated into personalised applicators. The mean accuracy of the needle tip placement was 3.9 mm. All values were < 8 mm. The curvature constraints have been used to verify that the target area can be reached. A personalised 3D-printed template with curvature constraints has been proposed as an improved method for the practice of brachytherapy in case of cervical cancer with distal parametrial extension or lower vaginal involvement. Further development and research are required to optimise the concept and verify clinical feasibility.