Combined ultrasound and photoacoustic C-mode imaging system for skin lesion assessment

Abstract

Accurate assessment of the size and depth of infiltration is critical for effectively treating and removing skin cancer, especially melanoma. However, existing methods such as skin biopsy and histologic examination are invasive, time-consuming, and may not provide accurate depth results. We present a novel system for simultaneous and co-localized ultrasound and photoacoustic imaging, with the application for non-invasive skin lesion size and depth measurement. The developed system integrates an acoustical mirror that is placed on an ultrasound transducer, which can be translated within a flexible water tank. This allows for 3D (C-mode) imaging, which is useful for mapping the skin structure and determine the invasion size and depth of lesions including skin cancer. For efficient reconstruction of photoacoustic images, we applied the open-source MUST library. The acquisition time per 2D image is <1 s and the pulse energies are below the legal Maximum Permissible Exposure (MPE) on human skin. We present the depth and resolution capabilities of the setup on several self-designed agar phantoms and demonstrate in vivo imaging on human skin. The setup also features an unobstructed optical window from the top, allowing for simple integration with other optical modalities. The perspective towards clinical application is demonstrated.

Research on Water Invasion Law and Control Measures for Ultradeep, Fractured, and Low-Porosity Sandstone Gas Reservoirs: A Case Study of Kelasu Gas Reservoirs in Tarim Basin

“…Lv Zhikai et al analyzed the connectivity of reservoirs and pointed out optimization countermeasures for the well pattern and production system of gas wells [26]. Li Guoxin et al analyzed in depth the factors affecting the recovery of tight gas reservoirs and established a development countermeasure system to match the characteristics of the gas reservoirs in the area, improving the recovery of tight gas reservoirs [27][28][29][30]. Fan H C et al pointed out that, in the case of water invasion in fractured gas reservoirs, natural gas primarily exists in the forms of bypass sealing gas, barrier sealing gas, and water-blocking sealing gas [31].…”