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MRI Compatible Robotic Positioning System for an Arborizing Multiport Catheter

出版	University of Texas, 2019
URL	http://books.google.com.hk/books?id=nPuhzwEACAAJ&hl=&source=gbs_api

註釋Glioblastoma is a cancer of the central nervous system that continues to have low survivability, with a five-year survival rate of less than five percent. One novel method of treatment being explored is convection enhanced delivery (CED), a method of bypassing the blood-brain barrier and delivering targeted drugs directly into the cancerous region. Previous clinical trials using CED have not shown improvement in patient survival, possibly due to a failure of the drug to adequately cover the margins of the tumor. An arborizing multiport catheter has previously been developed to increase drug distribution volume by infusing simultaneously through multiple needles. This thesis describes the development of an MRI-compatible system for remotely positioning the arborizing catheter, allowing for precision control of drug infusion points while the infusion is viewed in real time from an MRI control room. Actuation mechanisms, made using all MRI-compatible materials, were developed to control microneedle deployment, main cannula deployment, and main cannula rotation. Position input to the actuation mechanisms was controlled using electromechanical stepper motors. A transmission system of rotating rods was employed to keep the stepper motors a safe distance from the MRI scanner. A digital camera was used to obtain position data during in-plane movements of the device. This data was used to determine repeatability of the device with respect to main cannula deployment, main cannula rotation, and individual microneedle deployment. Backlash hysteresis and stick-slip behaviors were also examined. Microneedle deployment repeatability ranged between 0.05 and 0.24 mm, and main cannula insertion repeatability was 0.14 mm degrees. Backlash hysteresis in microneedle deployment was substantial, at 0.7 mm for the center microneedle and ranging from 1.2 to 2.0 mm for needles deploying from the side of the cannula. The transmission was a minor component position loss, accounting for less than sixteen percent of total backlash in any device. This prototype demonstrated the feasibility of these mechanisms for MRI-compatible positioning of the arborizing catheter. The rotating rod transmission lines proved to be a functional means of MRI-compatible power transmission