High-speed photoacoustic tomography

Traditional diagnostic imaging technologies—including ultrasound, x-ray computed tomography, and magnetic resonance imaging—have dramatically improved patient care in the clinic. However, these technologies still have limited ability to detect small lesions. In most cases, the detectable lesions are ~1 cm in dimeter, corresponding to ~10^9 cells (including circulating and microscopic metastatic deposits) and representing ~2/3 of the natural history of a cancer [1]. Consequently, the window of opportunity for treatment before a tumor reaches its lethal state is narrow. Hence, it is imperative to develop novel technologies capable of detecting neoplasia early. Non ionizing biomedical optical imaging is highly desirable because of its rich contrast. In particular, optical absorption—to which photoacoustic tomography is sensitive—can be used to obtain physiological parameters such as the total concentration and oxygenation of hemoglobin is related to hyper-metabolism. Since both angiogenesis and hypermetabolism are hallmarks of cancer, photoacoustic tomography can potentially provide early-cancer detection