Toward in vivo biopsy of melanoma based on photoacoustic and ultrasound dual imaging with an integrated detector.

Melanoma is the most dangerous type of skin cancer with high lethal rate. Tumor thickness and tumor-associated vasculature are two key parameters for staging melanoma. Previous techniques for diagnosing melanoma have insurmountable restrictions, such as invasive, low specificity, or inaccurate depth measurement. Here we develop an integrated photoacoustic (PA) and ultrasound (US) imaging system dedicated to overcome these limitations. An integrated detector with sound-light coaxial/confocal design and flexible coupling mode is employed for the combined PA/US imaging strategy. PA imaging results enable a clear characterization of tumor angiogenesis with high resolution and high contrast. Furthermore, accurate thickness measurements of melanoma in different stages can be resolved with the simultaneously obtained PA/US image. Phantom experiments and in vivo animal experimental results demonstrate the integrated PA/US system could provide potential for noninvasive biopsy of melanoma.