Graduation Semester and Year

2008

Language

English

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering

Department

Bioengineering

First Advisor

Karel Zuzak

Abstract

Cholecystectomy is one of the most common procedures occurring in United States to cure gall bladder diseases. There are two means of performing this procedure, Open Cholecystectomy and Laparoscopic Cholecystectomy, the later one being more frequent. The critical issue while performing Cholecystectomy is injury to Common Bile Duct (CBD) which could cause post procedural complications. Since the CBD is under fat layer it is important to image and locate the CBD during the procedure. The novel fluorescence imager developed in this project would help visualize the CBD by using the fluorescence properties of Indocyanine Green, to be injected into the body or bilirubin, already existing in bile. The instrument using ICG as a fluorophore has been characterized for its penetration depth to view fluorescence using an intralipid model, determining the best and possible fluorescence concentration that would give maximum fluorescence photons at the same time within the limits of the concentration prescribed for human dosage. The system incorporates a unique combination of short pass-long pass filter combination at the source and detector end respectively to provide excitation and detect emission. The filters are designed in accordance with the absorption and emission characteristics of individual fluorophore in different medium. The best fluorescence concentration was found to be 0.015 mg/ml. Depth analysis was performed for ICG mixed with water, going deeper in a 1% intralipid solution used as model to mimic tissue and fat properties. A vernier height guage was coupled to a capillary holder, which held the capillary containing the fluorophore. Two separate analyses were carried out, ICG mixed with human bile and aqueous ICG solution both having an approximate concentration of 0.015 mg/ml. Contrast to background and signal to noise ratio were computed at each depth to find the maximum depth the system can visualize. The maximum depth of penetration was found to be 11 mm below the surface of intralipid when ICG was mixed with bile and 20 mm below the surface for aqueous ICG. The threshold for contrast to background was set based on beef fat measurement.

Disciplines

Biomedical Engineering and Bioengineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

Download

Share

COinS