Image analysis of patient data from the hybrid photoacoustic-ultrasound tomography system PAM3

The PAM3 system is a hybrid photoacoustic-ultrasound system for imaging the breast. The ultrasound mode enables extraction of speed-of-sound (SOS) maps that can be used to improve photoacoustic (PA) reconstruction. SOS holds information that can be used potentially for tissue characterization and discrimination. PA computed tomography images were reconstructed using an iterative model-based optimization framework. An image analysis pipeline has been developed to analyze the PA/US images and compare them with contrast-enhanced Magnetic Resonance (ceMR) images. We imaged patients using PAM3 in a study approved by the Medical Ethics Review Board. Patients with a tumor suspicious for malignancy, based on conventional diagnostic imaging, were asked to participate. All patients received X-ray mammography, ultrasound imaging and ceMR imaging. The preliminary results on a patient with a fibroadenoma demonstrate that combining multi-wavelength PA and sound speed imaging is potentially valuable for visualizing breast cancer. From PA we obtain functional information with sound speed providing structural information.