Dual-wavelength photoacoustic sentinel lymph node imaging (Conference Presentation)

In melanoma patients, sentinel lymph node (SLN) biopsy is crucial for staging, prognosis, and treatment planning. Traditional methods using technetium and blue dye have limitations such as radiation exposure and logistical issues. Photoacoustic imaging (PAI) with indocyanine green (ICG) offers a non-radioactive, high-resolution alternative for real-time SLN mapping and biopsy guidance. We evaluated SLN imaging using LED-based (Acoustic X, Cyberdyne Inc., Tsukuba, Japan) and laser-based (PhotoSonus X, EKSPLA, Vilnius, Lithuania; Verasonics, Kirkland, United States) PAI systems on healthy volunteers and melanoma patients. After injecting ICG upstream of the lymph node, interleaved PAI (820 and 940 nm) and ultrasound images were acquired. The 940/820 nm ratio images helped differentiate ICG-labelled SLNs from regular lymph nodes. Dual-wavelength PAI successfully visualized SLNs in melanoma patients. Our findings highlight the potential of dual-wavelength PAI in improving SLN mapping for biopsies in melanoma patients.