Coregistered three-dimensional ultrasound and photoacoustic imaging system for ovarian tissue characterization

Abstract

Ovarian cancer has the highest mortality of all gynecologic cancers, with a five-year survival rate of only 30% or less. Current imaging techniques are limited in sensitivity and specificity in detecting early stage ovarian cancer prior to its widespread metastasis. New imaging techniques that can provide functional and molecular contrasts are needed to reduce the high mortality of this disease. One such promising technique is photoacoustic imaging. We develop a 1280-element coregistered 3-D ultrasound and photoacoustic imaging system based on a 1.75-D acoustic array. Volumetric images over a scan range of 80 deg in azimuth and 20 deg in elevation can be achieved in minutes. The system has been used to image normal porcine ovarian tissue. This is an important step toward better understanding of ovarian cancer optical properties obtained with photoacoustic techniques. To the best of our knowledge, such data are not available in the literature. We present characterization measurements of the system and compare coregistered ultrasound and photoacoustic images of ovarian tissue to histological images. The results show excellent coregistration of ultrasound and photoacoustic images. Strong optical absorption from vasculature, especially highly vascularized corpora lutea and low absorption from follicles, is demonstrated.

A Framework of Photo Acoustic Imaging for Ovarian Cancer Detection by Galvo-mirror System

“…The system has been applied to image normal porcine ovarian tissue for ex vivo use. However, this system faces two limitations: one is about the beam steering angel, and the other is about the elevation resolution [1].…”

“…However, employing the combination of ultrasound and photo acoustic could make us able to have both mechanical resolution and optical absorption contrast together as a Photo acoustic image. In other words, Photo acoustic imaging could be employed for identifying cancer at early stages [1,4].…”

“…Photo-acoustic imaging (PAI) is an emerging biomedical imaging technique in which a short-pulsed laser beam penetrates diffusely into a tissue sample [1] (Potential Role of Co-registered Photo-acoustic and ultrasound). Aguirre et al develops co-registered 3-D ultrasound and photo acoustic imaging system a 1280-element (10 × 128) and 1.75-D acoustic array.…”

“…One of the best imaging modality, being known in this area, is Photo acoustic. This technique has demonstrated great potential for imaging ovarian tissues [1,3].…”

“…Photo acoustic imaging known as opto-acoustic or thermo-acoustic imaging, is able to image human and animal organs equipped with high contrast and high spatial resolution simultaneously [1].…”