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. 2017 Nov 26;9:10–20. doi: 10.1016/j.pacs.2017.11.001

Fig. 5.

Fig. 5

Penetration depth measurement of PLED-PAI. A) Experimental configuration includes chicken breast tissue with pencil lead 3.2 cm deep. B) Photoacoustic image of pencil lead 1.8 cm deep with a frame rate (FR) of 30 Hz C) Depth of 2.4 cm when FR = 30 Hz. D) Depth of 3.2 cm when FR = 6 Hz. By increasing the depth, the photoacoustic system acquires more averages (decrease the frame rate) to improve SNR. E) Depth of 3.2 cm when FR = 0.6 Hz F) B-mode ultrasound image of pencil lead 3.2 cm deep with a frame rate of 0.6 Hz. The ultrasound resolution at 10 MHz does not clearly discriminate the target. G) Photoacoustic image of pencil lead 3.2 cm deep when FR = 15 Hz. The SNR decreases by increasing the frame rate. Object is poorly defined with low contrast. H) Signal to background noise as a function of depth and frame rate. Panels I-K are blood samples below chicken breast tissue. Panel I is a frame rate of 0.15 Hz J) Photoacoustic image of blood sample 2.2 cm deep when frame rate of 0.15 Hz K). Signal-to-background noise as a function of depth and frame rate for blood sample inside the chicken breast. If the contrast is lower than the detection limit (S/N < 3), then the specimen cannot be detected.