BACKGROUND/AIMS: Since the majority of skin diseases are known to be accompanied by structural alterations, research efforts are focused on the development of various novel diagnostic techniques capable of providing in vivo information on the skin structure. An essential parameter here is spatial resolution. In this paper we demonstrate the capabilities of optical coherence tomography (OCT) in detecting in vivo specific features of thin and thick skin. A particular focus is made on the identification of OCT patterns typical of certain pathological processes in skin, by performing parallel histological and tomographical studies. METHODS: To obtain images of the skin, we used a compact fiber OCT system developed at the Institute of Applied Physics of the Russian Academy of Sciences. A low coherence source (superluminescent diode) operated at a wavelength of 1280 nm; the output power was 0.5-2 mW. This power is low enough to conform to the ANSI safety standards for light exposure. The in-depth resolution limited by the spectral bandwidth (40-50 nm) of the probing light was approximately 20 &mgr;m. The lateral resolution determined by the probe light focusing ranged from 15 to 30 &mgr;m. In this series of experiments the maximum depth of imaging did not extend beyond 1.5 mm. Obtaining images of skin regions 2-6 mm long took 2-4 s. OCT capabilities for imaging normal skin of different localization and some skin diseases were studied in 12 healthy volunteers and 24 patients. RESULTS: OCT imaging of the skin can detect in vivo such general pathological reactions of the human body as active inflammation and necrosis. OCT is useful for in vivo diagnosis of some specific processes in the skin, including hyperkeratosis, parakeratosis and formation of intradermal cavities. OCT imaging is noninvasive and therefore allows frequent multifocal examination of skin without any adverse effects. OCT can perform monitoring of disease progress and recovery in the course of therapy. Morphometric studies, measurements of the depth and extension of skin pathology within the human body can be easily performed by OCT. CONCLUSIONS: OCT allows imaging of subsurface soft tissues with the spatial resolution of 15-20 &mgr;m, a resolution one order of magnitude higher than that provided by other clinically available noninvasive diagnostic techniques. An imaging depth of up to 1.5-2 mm, given by current OCT technology, is sufficient to examine the skin. Real time OCT imaging can provide information not only on the structure, but also on some specific features in the functional state, of tissues. OCT imaging is a noninvasive technique, i.e., OCT does not cause trauma and has no side effects since it utilizes radiation in the near infrared wavelength range at a power as low as 1 mW.
The study of patients with systemic lupus erythematosus revealed the close association of the disease with measles--or a related virus. High titres of antibodies to measles virus were found in patients that correlated with the course of the disease. Immunofluorescence tests revealed measles virus or a related antigen in lupus-affected tissues. Inclusion bodies consisting of paramyxovirus-like ribonucleoprotein structures were regularly detected in both affected tissues and leukocytes. Molecular hybridization of measles virus RNA with DNA from the affected tissues showed that DNA transcripts of measles or a closely related virus are integrated in the cellular nuclear DNA. Possible pathogenetic mechanisms of the disease are discussed.
A multi-wirescanner for diagnostics of ionizing particle beams (e.g. both non-relativistic and ultra-relativistic charged particles; X-ray and gamma photons) is proposed and discussed in the paper. The scanner is based on measurement of yield of characteristic X-rays generated during the particle interaction with the wires made of different materials. The proposed scanner is developed and tested on the beam of electrons with energy of 40 keV. The quasimonochromatic characteristic X-rays and continuous background are clearly identified. The results of measurements of the transverse size, emittance, position and direction of beam propagation are presented and discussed. K : Beam-line instrumentation (beam position and profile monitors; beam-intensity monitors; bunch length monitors); Instrumentation for particle accelerators and storage rings-high energy (linear accelerators, synchrotrons); Instrumentation for particle accelerators and storage rings-low energy (linear accelerators, cyclotrons, electrostatic accelerators) 1Corresponding author.
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