UBC Theses and Dissertations
Toward an automated multimodal breast ultrasound imaging system Kelly, Corey
Breast cancer affects millions of women worldwide each year, and is responsible for hundreds of thousands of deaths. Mammography, the standard screening method for these cancers, underperforms for women with dense breast tissue, who account for half of all women under the age of 50. Given that these women are also at higher risk of developing breast cancer, there is a significant need for better screening methods to serve this population. In this thesis, we develop a breast imaging platform which combines several modalities that have been clinically shown to aid in the detection and staging of breast malignancies. This operator-independent, completely automated scan, simultaneously acquires B-mode ultrasound, absolute elasticity, Doppler flow, and photoacoustic tomography of the entire breast in 20 minutes. We describe the hardware and software components which comprise each of these imaging subsystems, and conduct a preliminary study testing the combined system by imaging a phantom which we designed to incorporate inclusions which are uniquely visible in either elasticity or photoacoustic imaging. The photoacoustic tomography system constitutes the most significant contribution, and as such is the primary focus of the thesis. We have designed, built, and tested a custom, fiber-based tissue illuminator to accommodate the unique scanning geometry of the automated breast ultrasound scanner upon which we have based our system. We have also developed a novel data reconstruction scheme which can account for the spatial non-uniformity of this illumination. We tested this system in vitro, as well as a purpose-built wire phantom. Finally, we developed a data processing pipeline which uses generative adversarial networks to improve the signal-to-noise ratio of our raw photoacoustic data, and implemented a state-of-the-art regularized reconstruction scheme to remove imaging and reconstruction artifacts. We tested this method using several phantoms, including an anatomically realistic blood vessel phantom generated from real breast imaging data.
Item Citations and Data
Attribution 4.0 International