Integrated Photoacoustic Pen for Breast Cancer Sentinel Lymph Node Detection

Abstract

Breast cancer is the most popular cancer for women. The sentinel lymph node (SLN) biopsy is significant for breast cancer treatment. Currently, SLN localization is normally based on visual observation and fluorescence imaging with low resolution due to the strong light scattering. In this study, an integrated Photoacoustic Pen (PAPen) is designed for SLN detection during breast cancer surgery. The PAPen is based on photoacoustic sensing with deeper penetration, which assists the surgeons to detect the SLN fast and accurately. The PAPen combines the ultrasound transducer for photoacoustic (PA) wave detection and the optical fiber for laser illumination. By scanning the detection target with PAPen, the PA signal of the contrast agent in the SLN by lymph drainage can be captured, which implicated the position of SLN for surgeons. The PAPen detects the PA signal update at 10 Hz and the detection depth is up to 50 mm, which can satisfy most breast cancer treatments. Both phantom and in-vivo studies are demonstrated in this work. The PAPen with enhanced flexibility and sensitivity will have great potential for SLN detection during breast cancer surgery.