Handheld array-based photoacoustic probe for guiding needle biopsy of sentinel lymph nodes

Abstract

Abstract. By modifying a clinical ultrasound array system, we develop a novel handheld photoacoustic probe for image-guided needle biopsy. The integration of optical fiber bundles for pulsed laser light delivery enables photoacoustic image-guided insertion of a needle into rat axillary lymph nodes with accumulated indocyanine green ͑ICG͒. Strong photoacoustic contrast of the needle is achieved. After subcutaneous injection of the dye in the left forepaw, sentinel lymph nodes are easily detected, in vivo and in real time, beneath 2-cm-thick chicken breast overlaying the axillary region. ICG uptake in axillary lymph nodes is confirmed with fluorescence imaging both in vivo and ex vivo. These results demonstrate the clinical potential of this handheld photoacoustic system for facile identification and needle biopsy of sentinel lymph nodes for cancer staging and metastasis detection in humans.

Performance benchmarks of an array-based hand-held photoacoustic probe adapted from a clinical ultrasound system for non-invasive sentinel lymph node imaging

“…The combined PA and US imaging system was developed around a commercial clinical US scanner (iU22, Philips Healthcare) and has been described previously [10][11][12]. In brief, a tunable dye laser (PrecisionScan-P, Sirah), pumped by a Q-switched Nd : YAG laser (PRO-350-10, Newport), produced 6.5 ns laser pulses at a repetition rate of 10 Hz, which illuminated tissue via bifurcated fibre bundles (CB18043, Fiberguide).…”

“…organic dyes and nanoparticles) contrast, high-resolution PA imaging can provide highly sensitive morphological, functional and molecular information about biological tissues [4][5][6]. Further, conventional ultrasonic scanners can serve as PA wave receivers, thus combining the high contrast of optical imaging and the high resolution of ultrasound (US) imaging [7][8][9][10].…”

“…We have previously reported in vivo PA and US mapping of rat sentinel lymph nodes (SLNs) using a hand-held probe adapted from a clinical US imaging system [10][11][12]. Clinically used dyes, including methylene blue (MB) and indocyanine green, have been successfully tested with this hand-held probe.…”

Breast sentinel lymph node biopsy with imaging towards minimally invasive surgery

“…Hence, deep SLN mapping can be measured using the photoacoustic signals non-invasively. Figure 3B shows an in vivo PAT-US image of the SLN and needle for various photoacoustic amplitudes [10,17].…”

How Can New Imaging Modalities Help in the Practice of Radiology?

“…Warfarin should be stopped 5-7 days prior to the procedure and may be resumed the day following biopsy. Heparin should be withheld 6-12 h prior to biopsy [62][63][64][65][66][67].…”