In photoacoustic tomography (PAT), measurement errors arise from optical fluence spatial and temporal variations caused by tissue optical absorption and scattering heterogeneities, system noise, and motion. These errors influence the estimation accuracy of blood oxygenation saturation (sO2). In this study, we introduce a sliding multi-pixel approach to mitigate the effect of measurement errors before computing sO2 maps. As a result, the sO2 estimation is both more accurate, as evaluated by residual fitting errors, as well as smoother. We conclude by presenting diagnostic results from PAT of 33 patients with ovarian masses imaged by our coregistered PAT and ultrasound system.
Ovarian cancer has the highest mortality rate among all other cancers related to reproductive system. We have developed co-registered ultrasound (US) and photoacoustic tomography (PAT) technique (US/PAT) for non-invasive diagnosis of ultrasound identified ovarian tissue. Ultrasound images provide structural information of human ovary and PAT provides information of blood vasculature and oxygen saturation inside the ovary. However, due to the lower contrast of transvaginal US images, it is not always easy to delineate the ovaries from the surrounding tissue, especially postmenopausal ovaries. Doppler US can identify large vessels around or inside the ovary if exist and also large celiac vessels which are often in the neighborhood of ovaries. If the region of interest (ROI) includes the surrounding celiac vessels, the tumor total hemoglobin and blood oxygen saturation cannot be quantified correctly. To optimize the selection of ROI for co-registered PAT imaging, we have developed co-registered display of Doppler US, ultrasound and photoacoustic for near real-time ovarian tissue diagnosis. Doppler images provide blood flow information of large vessels and assist co-registered gray-scale US to identify ROI. PAT maps out the total hemoglobin and oxygen saturation distributions. Data for Doppler imaging is collected using our customized commercial US machine which can simultaneously save US/PAT RF data. US RF data is used to reconstruct ultrasound and Doppler images. Conventional cross correlation technique assisted by advance image processing techniques is used to compute Doppler images. We report examples of how these co-displayed images help improve PAT mapping of tumor angiogenesis and oxygen saturation using phantom data.
It is important to provide timely information to surgeons on diagnosis of a suspicious ovarian tissue before excision to avoid unnecessary surgery, especially for young women. In this report, we introduce a new 3-D surface mapping technique to map ovarian tissue scattering properties by fitting the swept-source optical coherence tomography (SS-OCT) signals to a scattering model. We observed that lower scattering coefficients and heterogeneous spatial distribution were associated with malignant ovarian tissues, and higher scattering coefficients and homogeneous spatial distribution indicated benign ovarian tissues. The initial results suggest that the 3-D scattering map has potential to be an effective tool to characterize normal and malignant ovarian tissues.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.