Liver cancer ranks seventh in global cancer prevalence and stands as the third leading cause of cancer-related deaths. Surgical resection is considered the gold standard for treatment of liver malignancies and has witnessed a shift toward minimally invasive techniques in recent decades. Surgeons rely on laparoscopic observations, preoperative imaging, and laparoscopic ultrasound for image guidance. However, these methods pose challenges in accurately representing the complex three-dimensional (3D) structure of the liver in a two-dimensional (2D) view. Surgical navigation devices aim to enhance this process by providing additional information for improved lesion localization and vascular structure visualization with respect to tracked surgical instruments. This study's objective was to establish an electromagnetically guided laparoscopic liver resection workflow at Netherlands Cancer Institute – Antoni van Leeuwenhoek (NKI-AvL) to be implemented into clinical practice.

A method was developed for tracking instruments in laparoscopic surgery, with a focus on the laparoscopic sealer/ divider. An adapter was developed with an embedded electromagnetic sensor to allow tracking. Calibration employed a dedicated device, followed by a comprehensive validation process encompassing usability, sterilizability, attachment reproducibility, and calibration accuracy. The adapter was produced from a non-ferromagnetic material, ensuring sterilizability and straightforward surgeon attachment, exhibiting positive results in reproducibility and virtual visualization. Nevertheless, the calibration accuracy, at 2.5 mm, could be enhanced, primarily through calibration method adjustments. Additionally, a fast calibration method for the laparoscopic ultrasound (LUS) probe adapter was developed, involving a dedicated calibration tool. Validation assessments to ascertain its reproducibility showed positive results. However, accuracy measurements can be further improved as ultrasound calibration method evaluation showed a root mean squared error (RMSE) of 3.6 mm. This is important as the navigation performance relies on the calibration accuracy of the tracked LUS probe. The workflow for navigated laparoscopic liver resection was tested using a liver phantom. It demonstrated the navigation system's capacity to register preoperative and intraoperative images with a mean target registration error (TRE) of 3.7 mm and showed promising augmented reality views. Additionally, this test led to workflow enhancements related to liver sensor placement and visualization techniques.

The developed navigation workflow for laparoscopic liver resection integrated Aurora EM tracking, tracked laparoscopic instruments, and software for intraoperative liver 3D model visualization. While feasible in an operating setting during phantom tests, further enhancements in visualization and accuracy are needed. A clinical study will be conducted to determine intraoperative feasibility, providing valuable experience to technical physicians and surgeons. In the near future, the presented navigation method may enhance laparoscopic resection accuracy and reduce disease recurrence. A clinical study at NKI-AvL will soon validate this navigation system for clinical use.

The goal of seismic imaging is to create a model of the subsurface from samples of a transmitted wavefield that is reflected in soil layers.
The created model can be used to locate storage possibilities for CO2 or H2 or to find oil and gas reservoirs or other natural resources.
Seismic imaging relies on the propagation of wavefields, which can be computed by evaluating the Rayleigh integral, a process that often requires a lot of time and resources.
In this thesis we develop methods to reduce error in the computation of the Rayleigh integral whilst remaining time-efficient.
To achieve this we first give the derivation of the Rayleigh integral and provide a few methods to evaluate integrals numerically using interpolating polynomials.
Afterwards, we adapt the integration methods to the Rayleigh integral and arrive at the main algorithms for its evaluation, at the end we compare these algorithms.

We present the method that is currently used for the computation of the Rayleigh integral and a modification that extends the method to samples on a rectilinear grid.
The adjusted version of this method did not perform consistently in our results, although it achieved better results than the original method on average.
Secondly we present a combined interpolation method (that is, it interpolates the full integrand without taking advantage that one of the two functions in the integrand is known) named Simpson's rule, which only performed better in the high sample points per wavelength range with minimal noise.
An alteration to the method for semi-equidistant grids also did not perform consistently and is not worth the extra operations.
Next was the separate interpolation algorithm (this time taking advantage of the known part of the integrand), this method is difficult to implement and had only slightly better performance than the combined method.
The final method was an extension of the separate interpolation algorithm to non-equidistant grids, this method performed undoubtedly the best of all presented methods (often better by a factor of 15 compared to the currently used method), this method is therefore recommended for evaluating the Rayleigh integral.
The amount of operations needed for all presented methods is approximately the same and the execution time needed for the calculation depends on the implementation of the problem.

In conclusion, we found that the separate interpolation method for non-equidistant grids delivered the most accurate approximations of the Rayleigh integral. This method can be used in seismic imaging to increase the accuracy of models of the subsurface.

This work investigates low-cost three-dimensional (3D) ultrasound reconstruction from a two-dimensional (2D) hand-held probe with motion tracking. The best available motion tracking is an optical tracking system, which is expensive and requires external tracking hardware. Here, a low-cost manoeuvrable motion tracker, an inertial measurement unit (IMU) sensor, has been tested by comparing it with an optical tracking system. The motion of the probe has been divided into a rotation and translation movement. Comparing the IMU sensor rotation tracking with the optical tracking, while rotating 40 degrees, resulted in an average Pearson’s correlation of 0.99 ± 0.0056. The average Pearson’s correlation between the translation tracking of the IMU sensor and the optical tracking system, in a translation of 15 centimetres, was 0.13 ± 0.78. The rotation and translation tracking is used to reconstruct the ultrasound volume of a phantom. In a rocking motion reconstructed volume the horizontal distance between phantom features had a mean error of 45%, a vertical distance was reconstructed with a mean error of 0.25%. In a translation motion reconstructed volume these errors were 29% and 1.4% for respectively horizontal feature distance and vertical feature distance. This study demonstrates that an IMU sensor can be used to track the motion of the probe. The rotation tracking of the IMU sensor is comparable with the rotation tracking of an optical tracking system. The translation tracking of the IMU sensor is on average not comparable with an optical tracking system, however some translations have been tracked with a high correlation. A reason to explain the low average correlation of the translation tracking of the IMU sensor is the method of gravity vector correction in the accelerometer data. Future research should focus on the clinical evaluation of the rotation tracking and the development of an accurate translation tracking method by studying the initial gravity vector or looking at different translation tracking methods.

Conventional imaging techniques from medical ultrasound and seismic imaging are not suitable for multilayered domains where there is no separation between received reflection events. This happens in layered structures where the thickness of the individual layer is small with respect to the induced wavelengths. An example of these structures is the wall of a typical blast furnace. Imaging these domains require a method based on the interference pattern in the frequency domain. This method is already widely used for imaging concrete structures. However, these consists of only one or two layers. This study introduces a FullWaveform Inversion scheme which extends the usability of themethod to multilayered domains. Itminimizes the error between measurements and a forward model. To reduce the computation load, a simplified forward model based on a plane wave response in a vertically layered medium is adopted. Pre-processing steps are necessary to remove the effect of the source wavelet and to enhance the peaks and troughs positions. A sensitivity analysis provides information about the usability of the method. This shows only layers with standing wave frequencies in the range of the induced source wavelet can be imaged. Furthermore, results show it is impossible tomeasure the wave velocity and thickness of a single layer simultaneously given our simplified forward model. Multichannel measurements over an aperture of 500 mm are required to transform a spherical wave response to its plane wave equivalent in order to fit the forward model. Tapering the sides of the aperture is essential to reduce simulation artefacts. The inversion scheme is successfully tested on synthetic data of a blast furnace wall in the acoustic and elastic domain using realistic simulations of the measured data.

Energy-based surgical instruments are increasingly used in laparoscopic surgical procedures. For example, the ultrasonic scalpel enables tissue coagulation and -cutting by transferring a mechanical vibration to the tissue. Additionally, real-time sensing is implemented to improve the surgical procedures. Intraoperative ultrasonography is one of those real-time sensing techniques that allows the surgeon to visualize the anatomical surroundings of the surgical site. Previous literature research has shown that integration of ultrasonography into the ultrasonic scalpel would be a promising direction for the development of a ‘smart surgical instrument’. This research focusses on the integration of intraoperative ultrasonography into the ultrasonic scalpel. Based on detailed analyses of the currently existing technology, several integration directions are developed. The integration of an existing ultrasound probe into the ultrasonic scalpel is tested in a series of experiments. A functional prototype is designed and manufactured in which the Philips Eagle Eye Platinum ultrasound catheter is integrated into a LOTUS Torsion ultrasonic scalpel. The performance of the separate ultrasound catheter is assessed using tissue phantom with inserted silicone distortions. This is followed by experiments to test the performance of the integrated catheter. Based on the experiment results, an improved prototype design is proposed. The first proposed prototype design facilitates integration of the ultrasound catheter and the integrated Eagle Eye Platinum catheter covers the areas of interest in its field of view. It is shown that the tissue phantom that is grasped by the ultrasonic scalpel prototype can be assessed. Distortions in the tissue can be detected. Also sideward imaging, relevant during tumour-free margin measurements, is possible using the developed prototype. Several problems were encountered during the experiments. The underlying causes are analysed and multiple solutions are recommended, leading to the proposal of an improved prototype design. It can be concluded that the integration of ultrasound imaging into the ultrasonic scalpel is a feasible direction for the development of a ‘smart surgical instrument’.