An Introduction to Biomedical Optics

Splinter, Robert

doi:10.1201/9781420011838

Cited by 85 publications

(109 citation statements)

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“…5c). This indicates that the depth penetration, as defined as a combination of both absorption and scattering, and measured as the surviving intensity of light, is similar in both cases (4). Fitting an exponential function to these curves gives a characteristic depth penetration of 1.04 AE 0.04 and 0.97 AE 0.03 mm for ICG and SWNT respectively.…”

Section: Resultsmentioning

confidence: 95%

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Deep-tissue anatomical imaging of mice using carbon nanotube fluorophores in the second near-infrared window

Welsher

Sherlock

Dai

2011

Proc. Natl. Acad. Sci. U.S.A.

870

718

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Fluorescent imaging in the second near-infrared window (NIR II, 1-1.4 μm) holds much promise due to minimal autofluorescence and tissue scattering. Here, using well-functionalized biocompatible single-walled carbon nanotubes (SWNTs) as NIR II fluorescent imaging agents, we performed high-frame-rate video imaging of mice during intravenous injection of SWNTs and investigated the path of SWNTs through the mouse anatomy. We observed in real-time SWNT circulation through the lungs and kidneys several seconds postinjection, and spleen and liver at slightly later time points. Dynamic contrast-enhanced imaging through principal component analysis (PCA) was performed and found to greatly increase the anatomical resolution of organs as a function of time postinjection. Importantly, PCA was able to discriminate organs such as the pancreas, which could not be resolved from real-time raw images. Tissue phantom studies were performed to compare imaging in the NIR II region to the traditional NIR I biological transparency window (700-900 nm). Examination of the feature sizes of a common NIR I dye (indocyanine green) showed a more rapid loss of feature contrast and integrity with increasing feature depth as compared to SWNTs in the NIR II region. The effects of increased scattering in the NIR I versus NIR II region were confirmed by Monte Carlo simulation. In vivo fluorescence imaging in the NIR II region combined with PCA analysis may represent a powerful approach to high-resolution optical imaging through deep tissues, useful for a wide range of applications from biomedical research to disease diagnostics.near-infrared imaging | photoluminescence | principal component analysis imaging | dynamic contrast imaging | deep-tissue imaging

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Section: Resultsmentioning

confidence: 95%

“…The benefit of higher resolution unfortunately comes at the cost of limited tissue penetration depth (4). Absorption by biological tissue and water is one factor that leads to attenuation of signal proportional to the depth of the feature of interest.…”

mentioning

confidence: 99%

Deep-tissue anatomical imaging of mice using carbon nanotube fluorophores in the second near-infrared window

Welsher

Sherlock

Dai

2011

Proc. Natl. Acad. Sci. U.S.A.

870

718

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“…When they are modulated out of phase, existing system noise or any other background absorption would be significantly suppressed from the system, and the difference between the two signals would be amplified. Therefore, differential PA signals from those two wavelengths allow one to Figure 1 Human Hb molar extinction coefficient spectrum with arrows indicating two wavelengths of interest for the WM-DPAS system; re-plotted from data obtained from [18].…”

Section: Biomedical Applicationsmentioning

confidence: 99%

Wavelength‐Modulated Differential Photoacoustic Spectroscopy (WM‐DPAS) for noninvasive early cancer detection and tissue hypoxia monitoring

Choi

Mandelis

Guo

et al. 2015

Journal of Biophotonics

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This study introduces a novel noninvasive differential photoacoustic method, Wavelength Modulated Differential Photoacoustic Spectroscopy (WM-DPAS), for noninvasive early cancer detection and continuous hypoxia monitoring through ultrasensitive measurements of hemoglobin oxygenation levels (StO 2 ). Unlike conventional photoacoustic spectroscopy, WM-DPAS measures simultaneously two signals induced from square-wave modulated laser beams at two different wavelengths where the absorption difference between maximum deoxy-and oxyhemoglobin is 680 nm, and minimum (zero) 808 nm (the isosbestic point). The two-wavelength measurement efficiently suppresses background, greatly enhances the signal to noise ratio and thus enables WM-DPAS to detect very small changes in total hemoglobin concentration (C Hb ) and oxygenation levels, thereby identifying pre-malignant tumors before they are anatomically apparent. The non-invasive nature also makes WM-DPAS the best candidate for ICU bedside hypoxia monitoring in stroke patients. Sensitivity tunability is another special feature of the technology: WM-DPAS can be tuned for different applications such as quick cancer screening and accurate StO 2 quantification by selecting a pair of parameters, signal amplitude ratio and phase shift. The WM-DPAS theory has been validated with sheep blood phantom measurements.Sensitivity comparison between conventional singleended signal and differential signal.

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“…The principle of OCT will be described next. Optical coherence tomography is a non-destructive and noncontact imaging modality that reconstructs depthresolved images of biological tissue based on local optical property distribution in two-and three-dimensional layout (Gibson et al, 2006;Choma, 2004;Jiang et al, 1998;Jiang et al, 1997;Najarian, 2005;Splinter, 2006), whereas the physical reconstruction process can be found in signal processing literature (Najarian & Splinter, 2005;Splinter & Hooper, 2006).…”

Section: Optical Coherent Imagingmentioning

confidence: 99%