Monitoring Needle Biopsy of Sentinel Lymph Nodes Using Photoacoustic Image with Dynamic-FDMAS Beamformer

As a part of the diagnosis pathway for breast cancer, a needle biopsy of the sentinel lymph node (SLN) is taken for analysis. Photoacoustic imaging is a better approach for guiding a needle than ultrasound imaging. However, the photoacoustic image will be affected by clutter, phase aberration and artefact from the needle. In this study, a dynamic filter delay multiply and sum (D-FDMAS) beamformer was produced to reduce these effects and improve the SNR and contrast difference (CD) of imaging targets. The D-FDMAS beamformer with a sub-group of 16 elements (16 D-FDMAS) showed improvement in SNR of needle and inclusion (SLN) by 8.38 dB and 5.42 dB compared with the delay and sum (DAS) beamfomer. It also showed reduction in CD between the inclusion and needle by almost 12 dB compared with the filter delay multiply and sum (FDMAS) beamformer.