The design of a manually operated compliant mechanism steerable needle for high dose-rate brachytherapy of the prostate

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Prostate cancer is the most common cancer in men and third in terms of mortality. High dose rate brachytherapy is a common and effective treatment to treat this cancer. High dose rate brachytherapy requires the implantation of several needles into the prostate trough which a radiation source is introduced. This implantation can present a number of difficulties. Steerable needles have been proposed to address some of these difficulties. The literature review in Appendix A has identified a number of possible advantages using a steerable needle could have in high dose-rate brachytherapy of the prostate. This thesis aims to develop a steerable needle system enabling the surgeon to place a needle more accurately, combat pubic arch interference, and circumvent ureteral occlusion while not interfering in the general course of the procedure.

This steerable needle was developed according to several design guidelines and optimisation parameters. A mathematical model and simulation were used to predict the behaviour of the needle and identify which parameters influence its functioning. By developing a number of concepts and evaluating their performance according to the set design guidelines a final design was formulated. A phantom was developed to be able to evaluate the performance of the design. By comparing the performance of the developed steerable needle to commercially available non-steered needles we hope to show the possible performance benefit of the developed needle.

The steerable needle has shown to perform, at minimum, non-inferiorly to a commercially available non-steerable needle. A small cost-effectiveness analysis has shown the possibility of the developed system to be cost-effective. While the developed steerable needle allows a surgeon to steer a needle during needle implantation and possibly increase the needle endpoint accuracy, the question remains whether this will result in a more favourable outcome of the high dose-rate brachytherapy procedure.