Date of Award

2008

Degree Type

Thesis

Degree Name

Master of Engineering Science

Program

Biomedical Engineering

Supervisor

Dr. Aaron Fenster

Second Advisor

Dr. Terry Peters

Third Advisor

Dr. Jim Lacefield

Abstract

Breast cancer is the most common cancer among Canadian women. There is strong evidence that early detection and diagnosis of breast cancer improves both the survival rate and quality of life for these women. In this thesis, two technical developments aimed towards improving the sensitivity of breast cancer detection are presented and evaluated. First, the feasibility of detecting occult solid breast lesions using ultrasound velocity differences between malignant lesions and surrounding tissue is investigated. In this technique, the breast is placed on a flat backplate and imaged using 3D ultrasound. The difference in ultrasound velocity through solid lesions versus surrounding breast tissue produces a shift in the apparent elevation of the backplate in the resulting image. We provide a mathematical model to predict backplate elevation as a function of lesion thickness, and validate this model experimentally using agar phantoms. Our results suggest that this technique may be useful as an additional screening tool for detection of otherwise occult solid breast lesions. Second, a new needle guidance device for lateral stereotactic breast biopsy (SBB) is presented, which addresses the limitations of commercially available needle guidance hardware. Specifically, the new device provides: 1) an adjustable rigid needle support to minimize needle deflection within the breast, and; 2) an additional degree of rotational freedom in the needle trajectory, allowing the sampling multiple targets through a single skin incision. This device was compared to a commercial lateral guidance device in a series of SBB phantom experiments. Needle placement error using each device was measured for deep and superficial needle insertions in agar phantoms. The biopsy success rate for each device was estimated by performing biopsy procedures in certified SBB phantoms. In these experiments, SBB with the new lateral guidance device provided significant improvements in both needle placement error and biopsy accuracy.

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