692048 event 1787764045 1787764087 David Qin
BME PhD Defense Presentation

Date: 2026-08-21
Time: 2:30 - 4:30 pm EST
Location / Meeting Link: EBB 1004 (CHOA Room) / Zoom (https://gatech.zoom.us/j/8997267918?pwd=aDFuUWJjUFdRRGhGa01tQW16TDhuUT09)

Committee Members:
Stanislav Emelianov, PhD (Advisor); Costas Arvanitis, PhD; Richard Bouchard, PhD; Erin Buckley, PhD; Brooks Lindsey, PhD


Title: Development of Techniques for Improved Accuracy in Quantitative Photoacoustic Imaging

Abstract:
Photoacoustic (PA) imaging integrates the high contrast of optical methods with the spatial resolution of ultrasound, making it a powerful modality for noninvasive assessment of tissue physiology and pathology. It has broad potential applications in cancer diagnosis, treatment monitoring, and quantification of various biomarkers such as tissue oxygen saturation (SO₂). However, accurate quantitative PA imaging remains limited by various technical challenges, among which are: (1) depth-dependent attenuation of laser fluence, which confounds estimation of local chromophore concentrations, and (2) noise corruption in low-signal regions, which biases spectroscopic PA (sPA) biomarker estimates when noise-dominated pixels are included in region-of-interest (ROI) averages. This dissertation develops two complementary methods to address these challenges. In Aim 1, an experimental approach is established to estimate the effective optical attenuation coefficient of heterogeneous tissue without prior knowledge of tissue composition through combined ultrasound/PA imaging during controlled mechanical displacement of tissue. In Aim 2, a noise masking method is developed to improve the accuracy of ROI-based biomarker quantification in sPA imaging, using SO2 as a representative example. We demonstrate that including noise-dominated pixels in an ROI biases SO2 estimation toward physiologically plausible but inaccurate values, and that a residual-based pixel-wise thresholding method can reject these pixels and restore accuracy. Together, these aims yield experimentally grounded strategies for both fluence compensation and noise rejection that integrate readily into the conventional PA imaging workflow, improving the accuracy and robustness of quantitative PA imaging and supporting its translation into preclinical and clinical studies.

]]> Development of Techniques for Improved Accuracy in Quantitative Photoacoustic Imaging

 

]]> 221981 1788 100811