UBC Theses and Dissertations
A research platform for ultrasonic elastograpy based targeted prostate biopsy Schiro, Arthur Leland
Prostate cancer has been identified as a ubiquitous threat to the well being of North American men living past their fourth decade. An accurate diagnosis, enabling the selection of an appropriate treatment regime, is a key component to disease management. The current gold standard for diagnosis is the transrectal ultrasound guided prostate biopsy procedure, where predefined templates are used to select tissue sample sites. Unfortunately, this procedure is incapable of producing reliable results; causing multiple repeat biopsies to become common practice and motivating many men, in the face of uncertainty, to choose unnecessarily sever treatment options with undesirable side effects. Elastography has shown great potential in its ability to detect cancerous tissue, and may enable for the current systematic sample site selection biopsy procedure technique to be replaced by a targeted biopsy approach. This transition promises higher cancer yields and improved diagnostic reliability, while at the same time decreasing procedural side effects by reducing the number of required core samples. The objective of this thesis has been to integrate the elastography imaging modality into a standard prostate biopsy system. This system may then act as a research platform for determining the feasibility of an elastography based, targeted prostate biopsy procedure. Realization of this objective required the development of four primary components. First, a tissue excitation mechanism, developed outside of this thesis, was both analyzed for performance capability and augmented in order to improve a design limitation necessitating frequent maintenance. Second, a plastic bracket, enabling an unobtrusive rigid coupling between the excitation mechanism and ultrasound probe, was designed so that excitation forces may be transmitted into the prostate tissue during the standard biopsy procedure. Third, a sensor was designed which is capable of accurately detecting biopsy needle insertion depth by tracking biopsy gun position using an optical absolute position sensor. And fourth, code was developed for enabling an evaluation of system performance by performing elasticity measurements. This code was used to process elastography data, collected from phantom and human subjects, in order to obtain a preliminary system validation.
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