China
Africa
Explore chapters and articles related to this topic
Noninvasive Tests
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
Hemant Kumar Kar, Gunjan Verma
Diffuse reflectance spectroscopy (DRS) has been used for more than 50 years to objectively measure skin pigmentation. This technique is based on different approaches to the analysis of light reflected by the skin [12].
Modelling and analysis of skin pigmentation
Published in Ahmad Fadzil Mohamad Hani, Dileep Kumar, Optical Imaging for Biomedical and Clinical Applications, 2017
Ahmad Fadzil Mohamad Hani, Hermawan Nugroho, Norashikin Shamsudin, Suraiya H. Hussein
Diffuse reflectance spectroscopy (DRS) is a spectroscopy technique that measures the characteristic reflectance spectrum produced as light passes through a medium (Figure 4.29). The primary mechanisms are absorption and scattering, both of which vary in wavelength in order to produce a recorded reflectance spectrum. This spectrum contains information about the optical properties and structure of the medium being measured [24].
Noninvasive Sensing of Serum sRAGE and Glycated Hemoglobin by Skin UV-Induced Fluorescence
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Vladimir V. Salmin, Tatyana E. Taranushenko, Natalya G. Kiseleva, Alla B. Salmina
As an example, results of clinical trials to test the efficacy and reliability of the original technique for a comprehensive assessment of microcirculatory alterations in patients with diabetes mellitus have been reported. The diffuse reflectance coefficient of skin in the spectral range from 500 to 600 nm was determined based on diffuse reflectance spectroscopy. An experimental setup includes a spectrometer (FLAME, Ocean Optics, USA), an illumination device (broadband tungsten halogen radiation source HL-2000-HP-232R, Ocean Optics, USA), a fiber-optic probe (R400-7, Ocean Optics, USA) with seven fibers (1 – readout, 6 – lighting), personal computer, and Ocean View software (Ocean Optics). To assess the fluorescence of biological tissue, the method of fluorescence spectroscopy was used, and analysis of blood flow and tissue perfusion was done with the laser Doppler flowmeter. Registration of the amplitude of fluorescence signal of biological tissue and perfusion parameters was carried out simultaneously in one tissue area using the LAZMA MC diagnostic complex (NPP LAZMA LLC, Moscow, Russia). The device includes a laser module and an optical fiber probe. It was found that the diagnostic volume and depth of probing in the spectral region of the Q absorption bands of total hemoglobin (540–580 nm) were 1.0–1.3 mm3 and 0.4–0.5 mm, respectively. Additionally, according to the diffuse reflectance spectra obtained at a specific point of the skin, the hemoglobin index was calculated to assess its quantitative content in the tissue, and the degree of oxygenation of hemoglobin was determined. The authors found that hemoglobin was involved in the formation of diffuse reflectance spectra of the skin (in the visible and near-infrared ranges), proved that the calculation of the total hemoglobin index reflects the amount of blood in the skin, and suggested that high values of HbA1c have specific optical properties and can change diffuse reflectance spectra [45].
Advancing cervical cancer diagnosis and screening with spectroscopy and machine learning
Published in Expert Review of Molecular Diagnostics, 2023
Carlos A. Meza Ramirez, Michael Greenop, Yasser A. Almoshawah, Pierre L. Martin Hirsch, Ihtesham U. Rehman
As previously mentioned, another aspect on which no consensus can be reached between the spectroscopy and machine learning analysis is the number of spectra collected for subsequent supervised analysis (Figure 3b). For IR spectroscopy 1, 3, 10–20, spectra are collected per sample [17,58,61,66,73,83,84,86,88,89]. Raman spectroscopy has been found to be one of the most used spectroscopy techniques to analyze cancer samples, however the spectra collection ranges between 1–30 spectra per sample [11–13,19,54,56,62–65,69,70,72,74–76,87,90–92], being 3–8 the most common spectra collection range per sample, however this is not well established. In contrast the studies where diffuse reflectance spectroscopy (DRS) is being used, only 1 to 2 spectra are collected per sample [20,57,81]. The minority of spectroscopy techniques such as mass spectrometry (MS), and nuclear magnetic resonance (NMR), use 50 to 1200 m/z [85], and 64 or 128 free induction decays (FUD) into 32 k data points [59,68], respectively.
Contemporary evidence on colorectal liver metastases ablation: toward a paradigm shift in locoregional treatment
Published in International Journal of Hyperthermia, 2022
Yuan-Mao Lin, Reto Bale, Kristy K. Brock, Bruno C. Odisio
Besides imaging assessment, intraprocedural pathology assessment can provide clinical information that has prognostic significance for LTP. The identification of viable Ki-67-positive tumor cells from the tissue fragment adherent to electrodes or tissue obtained from the biopsy of the tumor center and the suspected minimal margin of the ablation zone has been reported to be associated with LTP and OS [91–93]. A prospective study performed a biopsy of the ablation zone showing minimal margins <5 mm were likely to have biopsies with viable tumor cells (p = 0.019) [91]. In addition, immediate fluorescent assessment of ablation zone [94] or in vivo diffuse reflectance spectroscopy [95] has shown to be feasible for real-time identification of residual viable tumor cells.
Functionality of receptor targeted zinc-insulin quantum clusters in skin tissue augmentation and bioimaging
Published in Journal of Drug Targeting, 2021
Pawandeep Kaur, Diptiman Choudhury
Progress monitoring of recovery of internal injuries like surgical wounds always remained a matter of challenge. Some of the technologies that are used for this purpose include a near-infrared optical scanner (NIROS), diffuse reflectance spectroscopy (DRS), multispectral imaging (MSI), laser speckle imaging (LSI), laser Doppler imaging (LDI), hyperspectral imaging (HSI), and spatial frequency domain imaging (SFDI), etc [1,2]. But some of the major challenges that remained associated with these technologies include technical complexity, low detection level, low penetration depth, detection depth, and expense [3–10]. Other than these techniques metal-organic frameworks (MOFs) or bioMOFs showing luminescence properties can be used for bioimaging purposes [11–13]. Recently metal (Cu, Ag, and Au) protein quantum cluster has caught the attention of the researchers for targeted delivery and efficient bioimaging [14–16]. Quantum clusters (QCs) are luminescent (fluorescent or phosphorescent) clusters that may associate with crystalline quantum dots (QDs) of 1–10 nm size or amorphous hetero atoms [17]. Quantum clusters have high emission rates, large Stokes shift, and photo-stability [18,19]. The QCs can be synthesised by using any reducing agent such as NaBH4, alkyl thiol, or glutathione or can be prepared by using proteins, peptides, amino acids, DNA, and dendrimers, etc [20–22]. At basic pH the aromatic groups of amino acids of the protein start donating electrons helps in reducing the metal and disulphide bonds present in protein can stabilise the nucleated cluster [20, 23].