A review of the optical properties of biological tissues

Cheong, Wai Fung; Prahl, Scott A.; Welch, Ashley J.

doi:10.1109/3.64354

Cited by 2,326 publications

(1,596 citation statements)

References 61 publications

(26 reference statements)

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“…[45][46][47] Absorption and scattering coefficients of tissues are factors responsible for several effects of light-tissue interaction; however, the optical properties of the same tissue may differ among patients. 48 Despite these considerations, it is known that light penetration into the tissue is proportional to its wavelength when considering the UV-near infrared range, i.e., the longer the wavelength, the deeper is the light penetration.…”

Section: Discussionmentioning

confidence: 99%

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Mima

Pavarina

Dovigo

et al. 2010

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, an

141

130

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Objective. In vivo studies of antimicrobial PDT in animal models of oral candidosis are scarce and the association of porphyrin and LED light has not been evaluated for in vivo photoinactivation of Candida. In this study the effectiveness of photodynamic therapy (PDT) on the inactivation of Candida albicans in vivo was evaluated. Study design. Seventy-one 6-week-old female Swiss mice were immunosuppressed, provided tetracycline to their drinking water, then orally swabbed with a suspension of C. albicans (10 7 CFU/mL). Four days after oral inoculation, PDT was performed on the dorsum of the tongue after topical administration of Photogem at 400, 500, or 1000 mg/L and followed 30 minutes later by illumination with LED light (305 J/cm 2 ) at 455 or 630 nm (n ϭ 5 each). After swabbing to recover yeast from the tongue, the number of surviving yeast cells was determined (CFU/mL) and analyzed by ANOVA and Holm-Sidak tests (P Ͻ .05). Animals were humanely killed, and the tongues surgically removed and processed for histological evaluation of presence of yeast and inflammatory reaction. Results. PDT resulted in a significant reduction in C. albicans recovered from the tongue (P Ͻ .001) when compared with mice from the positive control group. There was no difference between the concentrations of Photogem and LED light wavelengths used. Histological evaluation of the tongue revealed that PDT causes no significant adverse effects to the local mucosa. Conclusion. PDT promoted significant reduction in the viability of C. albicans biofilm without harming the tongue tissue.

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Section: Discussionmentioning

confidence: 99%

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Mima

Pavarina

Dovigo

et al. 2010

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, an

141

130

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“…Interpretation of tissue autofluorescence is complicated by the intrinsic scattering and absorption properties of the tissue, rendering autofluorescence measurements significantly more complicated than measurement of fluorophores in solution. Scattering cross sections are quite high in tissue 4 which can result in a distortion of the fluorescence signal. In various optical configurations used for measuring fluorescence, the scattering in tissue can cause apparent changes in the spectral shape of detected fluorescence.…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

Spectrroscopic Sensing of Cancer and Cancer Therapy: Current Status of Translational Research

Bigio

Bown²

2004

Cancer Biology & Therapy

143

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Various types of optical spectroscopy have been investigated as methods to effect a non-invasive, real-time in-situ assessment of tissue pathology. All of these methods have one basic principle in common: the optical spectrum of a tissue contains information about the biochemical composition and/or the structure of the tissue, and that information conveys diagnostic information. The biochemical information can be obtained by measuring absorption, fluorescence, or Raman scattering signals. Structural and morphological information may be obtained by techniques that assess the elastic-scattering properties of tissue. These basic approaches are useful for the detection of cancer as well as for other diagnostic applications such as hemoglobin saturation, intra-luminal detection of atherosclerosis, and simply the identification of different tissue types during procedures. Optical spectroscopic measurements can also be employed in the management of disease treatment. The site-specific pharmacokinetics of chemotherapy and photodynamic therapy agents can be used to customize dosage to the patient, and diagnostic spectroscopy can be used to monitor response to treatment. In recent years clinical studies have provided indications of potential efficacy, and some of these modalities are now entering a translational research stage, with an eye to approval and commercialization. A benefit of these methods is their inherent low cost and ease of implementation, generally mediated with small portable instruments, not requiring any specialized facilities, and eventually not requiring expert interpretation. This paper reviews briefly the most common methods of diagnostic optical spectroscopy, and reviews in greater depth recent clinical translational research invoking scattering spectroscopy as the enabling technology, which has been the experience of the authors.

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“…The size and topology of non-erythrocyte cells ensures that light is scattered in all directions within the tissue (Cheong 1990). For this reason, the instantaneous distribution of light within tissue does not correlate with structural order in the tissue.…”

Section: Optical Properties Of the Skin And Bloodmentioning

confidence: 99%

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

Cobb¹,

Claremont²

2001

Medical Engineering & Physics

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An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot. Jonathan Edwin CobbPlantar ulceration is a complication of the diabetic foot prevalent in adults with type 11 diabetes mellitus. Although neuropathy, microvascular disease and biornechanical factors are all implicated, the mechanism by which the tissue becomes pre-disposed to damage remains unclear. Recent theories suggest that the nutritional supply to the tissue is compromised, either by increased flow through the arteriovenous anastomoses ('capillary steal' theory) or through changes in the micro vascu I ature (haemodynamic hypothesis). Clinical data to support these ideas has been limited to assessment of the unclad foot under rest conditions. A limitation of previous studies has been the exclusion of static and dynamic tissue loading, despite extensive evidence that these biornechanical factors are essential in the development of plantar ulceration. The present study has overcome these problems by allowing assessment of plantar blood flow, in-shoe, during standing and walking.The system comprises a laser Doppler blood flux sensor operating at 780nm, load sensor, measurement shoe, instrumentation, and analysis software. In-vitro calibration was performed using standard techniques. An in-vivo study of a small group of diabetic subjects indicated differences in the blood flux response between diabetic neuropaths, diabetics with vascular complications and a control group. For example, following a loading period of 120s, relative increases in response from rest to peak were: Control (150% to 259%), Vascular (-70% to 242%), Neuropathic (109%-174%) and recovery times to 50% of the peak response were: Control (33s to 45s), Vascular (43s to >120s), Neuropathic (>120s). Dynamic re-perfusion rates (arbitrary units per millisecond) obtained for the swing phase of gait were: Control (6.1 a. u/ms to 7.9 a. u/ms), Vascular (4 a. u/ms to 6.2 a. u/ms), Neuropathic (2.3 a. u/ms to 4.5 a. u/ms).

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A review of the optical properties of biological tissues

Cited by 2,326 publications

References 61 publications

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Spectrroscopic Sensing of Cancer and Cancer Therapy: Current Status of Translational Research

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

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