Indocyanine green–assisted dental imaging in the first and second near‐infrared windows as compared with X‐ray imaging

Abstract

Indocyanine green (ICG) has been widely used in medical imaging, such as in retinal angiography. Here, we describe a pilot ex vivo study of ICG‐assisted near‐infrared fluorescence (NIRF) dental imaging in the first (700–950 nm for ICG‐NIRF‐I) and second (1000–1700 nm for ICG‐NIRF‐II) NIR windows using human extracted teeth; our study is compared with the traditional prevalent X‐ray imaging and NIR II illumination (NIRi‐II, 1310 nm) without ICG enhancement. The results show that ICG fluorescence has much better imaging contrast in both windows compared with NIRi‐II (by quantitatively comparing NIR intensity of the critical neighboring structures, such as enamel and dentin). Cracked teeth, notoriously hard to diagnose by dental X‐ray and computed tomography, were clearly profiled in NIRF dental imaging. An insidious occlusal caries, missing in X‐ray imaging, became a bright dot that was readily observed in ICG‐NIRF‐I images. For dental decay, NIRF imaging with ICG enhancement could clearly delineate the decay boundary. NIRF in both windows distinguished interproximal and occlusal superficial caries. Overall, ICG‐assisted NIRF dental imaging has unique advantages in identifying cracked teeth and insidious caries. The two NIR imaging windows used in our study might one day serve as noninvasive and nonionizing‐radiation methods for the diagnosis of critical dental diseases in situ.

Synthesis of praseodymium-and molybdenum- sulfide nanoparticles for dye-photodegradation and near-infrared deep-tissue imaging

“…In order to overcome the obstacle of scattering tissues, one possible method is performing the imaging within near-infrared (NIR) window (750-1100 nm), which is superior comparing with the ultraviolet-visible region. It can improve imaging quality vastly since it involves with the using of fluorophores emitting and the achieving of low levels of photon absorption [11][12][13][14][15][16].…”

Detection and analysis of enamel cracks by ICG‐NIR fluorescence dental imaging

“…The imaging platform, as used in our previous studies, 42,43 consists of NIR light sources (785 nm and 1300 nm laser sources) and NIR cameras. A bifurcated optical fiber is connected to the laser sources and is used to guide the laser light to expose the tooth samples.…”

“…The tooth holder was designed to be rotated 360°to observe the full morphological features of the tooth samples, as done in our previous studies. 42,43 The light source used for the first NIR window (700-950 nm) is an NIR laser diode (LD, Turnkey Raman Lasers-785 Series; Ocean Optics, Inc.) with a 785-nm filter (bandpass, Thorlabs, Inc.). The NIR I camera is a Mako U-130B (Allied Vision Technologies GmbH) with an 800-nm filter (longpass lens: 800 nm, Thorlabs, Inc.); this optical setting effectively blocks all the excitation photons from being received by the camera.…”

“…37,38 In our previous research we demonstrated the feasibility of indocyanine green (ICG) for dental imaging in the rat model and human extracted tooth. [39][40][41][42][43][44] We found that ICF-NIR fluorescent (ICG-NIRF) imaging could diagnose several typical diseases in human extracted teeth, such as caries lesions, decay, and insidious caries. 42,43 In particular, we compared ICG-NIRF dental imaging with X-ray imaging.…”

“…[39][40][41][42][43][44] We found that ICF-NIR fluorescent (ICG-NIRF) imaging could diagnose several typical diseases in human extracted teeth, such as caries lesions, decay, and insidious caries. 42,43 In particular, we compared ICG-NIRF dental imaging with X-ray imaging. We showed that cracks observed under ICG-NIRF dental imaging in the first (700-950 nm, ICG-NIRF-I) and second (950-1700 nm, ICG-NIRF-II) NIR windows failed to be recognized under X-ray imaging.…”