Comparative Evaluation of Photoacoustic Finder as an Alternative Method for Sentinel Lymph Node Detection in Breast Cancer Patients

Sentinel lymph node biopsy (SLNb) plays an important role in determining whether breast cancer has metastasized. The current standard method for SLNb is to use radioactive material and blue dye to detect sentinel lymph nodes (SLNs). However, this method has limitations such as radiation exposure, radioactive material disposal, and subjective evident interpretation of the blue dye. To overcome these limitations, we developed a non-radioactive detector, the photoacoustic finder (PAF), which utilizes the photoacoustic (PA) signal from the SLN's blue dye to identify SLNs instead of radioactive material. For evaluating the PAF, in this ex vivo clinical study, we compared the detection rate of standard SLN detection methods and PAF in resected SLNs from breast cancer patients. A total of 92 breast cancer patients were enrolled in the study, and 164 SLNs resected from the patients were analyzed. The detection rate was similar for gamma probe (85%, 139 of 164 SLNs) and PAF (85%, 139 of 164 SLNs), while the detection rate using blue dye visual inspection was 74% (122 of 164 SLNs), which was lower than gamma probe and PAF. These results affirm the validity of PAF as a non-radioactive alternative for detecting SLNs, indicating the potential feasibility of non-radioactive SLNb in future applications.