Photoacoustic imaging with low-cost sources; A review

Abstract

Benefitting from advantages of optical and ultrasound imaging, photoacoustic imaging (PAI) has demonstrated potentials in a wide range of medical applications. In order to facilitate clinical applications of PAI and encourage its application in low-resource settings, research on low-cost photoacoustic imaging with inexpensive optical sources has gained attention. Here, we review the advances made in photoacoustic imaging with low-cost sources.

Keywords: Laser diode; Light emitting diode; Low-cost; Medical imaging; Photoacoustic imaging.

Fig. 1

(a) Two-dimensional maximum amplitude projection PAM image of red blood cells over a 100 μm × 100 μm area. (b) 3D photoacoustic image of red blood cells over a 50 μm × 50 μm × 20 μm volume. (c) Zoomed in from (b) showing the biconcave structure of red blood cells. Reprinted from Ref. [36].

Fig. 2

(a) PAM image of a mouse ear, scale bar is 200 μm. (b) 200x optical microscopic image of the sample. Reprinted from Ref. [36].

Fig. 3

Photograph (a) and PAM image of ex vivo subcutaneous microvasculature on a mouse back. Reprinted from Ref. [37].

Fig. 4

PAM image (a) and photograph (b) of a porcine ovarian tissue. Reprinted from Ref. [41].

Fig. 5

PAM image (a) and photograph (b) of porcine ovarian tissue obtained by the laser scanning laser diode based OR-PAM system. Color bar represents normalized photoacoustic signal. Reprinted from Ref. [44].

Fig. 6

Top view (a) and side view (b) AR-PAM images of a mouse ear in vivo and PAM images of a human forearm in vivo at (c) epidermis (0–280 μm) and (d) dermis (280–550 μm) depth. (e) Contrast to noise ratio in human forearm as a function of depth. Scale bars represent 1 mm. Reprinted from Ref. [47].

Fig. 7

Co-registered photoacoustic and ultrasound images of a human proximal interphalangeal joint in sagittal (a) and transverse (c) view. (b) and (d) are anatomical-only ultrasound images from (a) and (c), respectively. Reprinted from Ref. [51].

Fig. 8

Photograph of rat brain, (a) before and (b) after removal of the scalp. (a–d) PAT images of rat brain 0, 2, 6, and 13 min after injection of ICG, respectively. (g) Photoacoustic signal level from ICG at the superior SS over time. Reprinted from Ref. [55].

Fig. 9

Co-registered photoacoustic and ultrasound images an arthritic (a) and healthy (b) human MCP joint. (c) Comparison of microvasculature density at normal and arthritic joints. Reprinted from Ref. [64].

Fig. 10

Ultrasound (a), photoacoustic (b), and co-registered (c) B-scan of an ex vivo human ocular globe with a choroidal melanoma tumor. (d) Perspective view of a 3D photoacoustic image of the sample. Parts identified on the images are pupil (PP), tumor area (TA), surface of the tumor (ST), and back of the eye (BE). Reprinted from Ref. [64].