Combined phased-array ultrasound and photoacoustic endoscope for gynecologic cancer imaging applications

Due to the high rate of gynecologic cancers among females, obtaining structural, functional, and molecular information from reproductive organs can potentially reveal diseases at their early stages of development . In this study, we aimed to develop a miniaturized phased-array ultrasound (US) and photoacoustic (PA) endoscope for potential imaging gynecologic cancer. The developed endoscope is built around a phased-array US transducer coupled to a fiber optic light delivery system. In particular, the proposed endoscope consists of a 64-element phased array US transducer, coupled to a light delivery system that includes six fiber optics. The probe dimensions allow for utilizing this device for imaging various types of gynecologic cancers in which the probe can become close to the pathologic tissue. Given the small imaging aperture, adaptive beamforming was developed to reconstruct co-registered US and PA images in 90-degrees sector scan format. The developed endoscope was tested in a set of tissue-mimicking phantom studies to determine its characteristics and its ability to form form co-registered volumetric US and PA images. In addition, spectroscopic PA (sPA) imaging of biocompatible, folate conjugated dye was tested to demonstrate the possibility of using the developed endoscope in imaging PA molecular contrast agents.