Abstract

Percutaneous liver biopsy is the gold standard among clinician's tool to diagnose and guide subsequent therapy for liver disease. Ultrasound image guidance is being increasingly used to reduce associated procedural risks but post–biopsy complications still persist. The major and most common complication is hemorrhage, which is highly unpredictable and may sometimes lead to death. Though the risk of mortality is low, it is too high for a diagnostic procedure. Post-biopsy care and additional surgical intervention to arrest hemorrhage make liver biopsy a costly procedure for health care delivery systems. Non-invasive methods to stop bleeding exist like electro–cautery, microwave, lasers, radio frequency, argon–beam, and High Intensity Focused Ultrasound (HIFU). All the methods except HIFU require direct exposure of the needle puncture site for hemostasis. HIFU is an ultrasound modality and uses mechanical sound waves for focused energy delivery. Ultrasound waves are minimally affected by tissue attenuation and focus internal targets without direct exposure. Human error in focusing HIFU renders it unusable for a medical procedure especially when noninvasive.

In this project we designed and developed an ultrasound guided prototype robot for accurate HIFU targeting to induce hemostasis. The robotic system performs percutaneous needle biopsy and a 7.5 cm focal length HIFU is fired at the puncture point when the needle tip retracts to the liver surface after sample collection. The robot has 4 degrees of freedom (DOF) for biopsy needle insertion, HIFU positioning, needle angle alignment and US probe image plane orientation. As the needle puncture point is always in the needle path, mechanically constraining the HIFU to focus on the needle reduced the required functionality significantly. Two mini c-arms are designed for needle angle alignment and US probe image plane orientation. This reduced the contact foot print of the robot over the patient providing a greater dexterity for positioning the robot. The robot is validated for HIFU hemostasis by a series of experiments on chicken breasts.

HIFU initiated hemorrhage control with robotic biopsy ensures arrest of post-biopsy hemorrhage and decreases patient anxiety, hospital stay, morbidity, time of procedure, and cost. This can also be extended to other organs like kidneys, lungs etc. and has widespread implications such as control of hemorrhage in post-biopsies in patients with reduced ability for hemostasis. This research opens a greater scope for research for automation and design making it a physician friendly tool for eventual clinical use.

Library of Congress Subject Headings

Diagnostic ultrasonic imaging; High-intensity focused ultrasound; Liver--Biopsy; Liver--Diseases--Imaging

Publication Date

10-14-2014

Document Type

Thesis

Student Type

Graduate

Degree Name

Imaging Science (MS)

Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)

Advisor

Navalgund A Rao

Advisor/Committee Member

Maria Helguera

Advisor/Committee Member

Vikram S Dogra

Comments

Physical copy available from RIT's Wallace Library at RC78.7.U4 A44 2014

Campus

RIT – Main Campus

Plan Codes

IMGS-MS

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