Optical biopsy

Photodiagnosis is the use of optical methods, based on fluorescence, for early diagnosis (optical biopsy)... 

Teamey, G. J., Brezinski, M. E., Bouma, B. E., Boppart, S. A., Pitris, C., Southern, J. R, and Eujimoto, J. G. 1997. In vivo endoscopic optical biopsy with optical coherence tomography. Science 276 2037-39. 

Several other optical techniques that rely on various mechanisms by which light interacts with matter, including absorption, reflection, elastic scattering and autofluorescence, are also being developed for cancer diagnostics. This section will discuss these optical biopsy techniques. 

Typical OCT systems provide a axial resolution of around 10 pm, ultra-high resolution is of the order of 1 pm. OCT systems typically use near infrared light with penetration depths in soft tissue of the order of a few millimetres. The mode of contrast in OCT is based on boundaries between zone of differences in refractive index within a specimen specifically, layers of different types of tissue can show up prominently on OCT images. Since the mid-1990s OCT has been suggested to be promising for real-time optical biopsy [42, 43], State-of-the-art probe systems have dimensions of a few millimetres and can be readily used at endoscopy. 

Fujimoto, J.G., C. Pitris, S.A. Boppart, and M.E. Brezinski. 2000. Optical coherence tomography An emerging technology for biomedical imaging and optical biopsy. Neoplasia 2 9-25. 

Optical Biopsy Would Be Fast, Painless, and Inexpensive, University of Illinois, Urbana-Champaign, ScienceDaily, 7/ 13/99, www.sciencedaily.com. 

Time-resolved DOT is sometimes used for optical biopsy of bone tissue, and to track heamodynamics and oxygen kinetics in muscle tissue. The instraments typically use the same setup as brain imaging [443], see Fig. 5.49, page 107. An application to DOT at the human forearm is described in [234]. The number of source and detection channels can often be reduced from the number in the setup shown in Fig. 5.49. 

An instrument for optical biopsy of bones based on a diode laser and a single TCSPC channel is described in [151, 152]. Other instruments use a tuneable synchronously pumped dye laser and a Ti Sapphire laser [414]. The lasers are switched into a single source fibre by a fibre switch. A single TCSPC channel records the diffusely reflected light and a reference signal split off from the source fibre. 

R. Cubeddu, Optical biopsy of bone tissue A step toward the diagnosis of bone pathologies. J. Biomed. Opt. 9, 474-480 (2004)... 

Keywords Biomedical optics In vivo imaging Optical biopsy Optical diagnosis Preclinical Clinical Benchtop to bedside Cancer Neurodegenerative diseases... 

J. G. Fujimoto et al.. Optical biopsy and imaging using optical coherence tomography. Nature Medicine, 1(9), 970-972 (1995). 

Mammograms are uncomfortable and embarrassing for women. NIR imaging [84] and an optical biopsy [85] may be performed. NIR radiation has been suggested as an alternative to both x-rays and physical, invasive biopsies. Breast cancer is one of the leading causes of death and disfigurement in woman, it is best detected early [85]. 

Industrial applications of Raman imaging fiberscope technology include remote sensing, waste tank inspection, in situ corrosion analysis, and reactor vessel monitoring. Potential clinical applications include minimally invasive optical biopsy. 

Figure 10. Schematics of various optical interactions with a tissue used for optical biopsy (Katz and Alfano,...

Recently, a fiber optic diagnostic analyzer with a trade name of Optical Biopsy System has been introduced by Spectra Science, Inc. of Minneapolis, Minnesota (FDA approved) to be used as an adjunct to lower gastrointestinal (GI) endoscopy for evaluation of polyps. These polyps are less than 1cm in diameter and can aid a physician to decide whether they should be removed. In this device, light is transmitted through a long fiber inserted in a colonoscope and is directed to a polyp. The autofluorescence from the polyp is collected back through the optical flber. 

Other spectroscopic techniques used for optical biopsy are ... 

Katz, A. Alfano, RR., Optical Biopsy Detecting Cancer with Ligjit, OSA TOPS on Biomedical Optical Spectroscopy and Diagnostics, VoL 3, Sevick-Muraca, E. Benaron, D. (eds.). Optical Society of America (1996), 132-135. 

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