0000000000400551
AUTHOR
Mindaugas Tamosiunas
Simultaneous detection of tissue autofluorescence decay distribution and time-gated photo-bleaching rates
ABSTRACT Experimental methodology for parallel measurements of in-vivo skin autofluorescence (AF) lifetimes and photo-bleaching dynamic has been developed and tested. The AF lifetime decay distributio ns were periodically collected from fixed tissue area with subsequent detection of the fluorescence intensity decrease dynamic at different time gates after the pulse excitation. Temporal distributions of human in-vivo skin AF lifetimes and bleaching kinetics were collected and analyzed by means of commercial time-corr elated single photon counting system. Keywords: TCSPC, skin autofluoresc ence, and photo-bleaching. 1. INTRODUCTION Laser induced time-resolved autofluorescence (AF) spectroscop…
Riga Group’s recent results on laser applications for skin diagnostics
Abstract The laser-related activities are reviewed of the Biophotonics Laboratory at UL Institute of Atomic Physics and Spectroscopy following the previous ICSQE-2018 conference. Four recent research projects are considered, including one EC Horizon-2020 project, two European Regional Development Fund (ERDF) projects and one project funded by the Latvian Council of Science (LCS). The projects are generally aimed at developing new optical methods and technologies for non-invasive in-vivo skin assessment to facilitate the early diagnostics of skin malformations (including cancers). Most of the projects explore novel approaches of camera-based biomedical imaging to the clinical diagnostics and…
Assessment of efficiencies of electroporation and sonoporation methods by using fluorescence RGB imaging method
Simple RGB method for fluorescence in vivo imaging is presented to assess efficiency of electroporation and sonoporation methods by measuring distribution and accumulation of green fluorescence protein (GFP) concentration. 20 laboratory measurements were performed on mice to test the method.
Optical coherence tomography and Raman spectroscopy for ex vivo characterization of canine skin and subcutaneous tumors: preliminary results
Cancer is one of the leading causes of companion animal mortality. Up to 30% of all canine and feline tumors appear on or directly under the skin. To date, only a limited number of studies applied biophotonics techniques for optical characterization and detection of tumors in pets. In this work, we acquired ex vivo optical coherence tomography (OCT) images and Raman spectra of native skin and the most common canine and feline skin and subcutaneous tumors; lipomas, mast cell tumors, and soft tissues sarcomas. Lipomas exhibited the most distinctive tissue morphology (i.e., honeycomb structure) and biochemistry (lipid-related Raman peaks of 1063, 1301, and 1652 cm-1). Moreover, lipomas had sig…
Fluorescence spectroscopy for estimation of anticancer drug sonodestruction in vitro
The effect of ultrasound exposure on bleomycin fluorescence and pharmacological properties is studied. Bleomycin was treated by ultrasound for 7 min. Bleomycin fluorescence was measured during ultrasound exposure by means of fiber-optic spectrometry. Cell colony test was used to evaluate blemycin cytotoxity before and after ultrasound exposure.
Remitted photon path length in human skin, skin phantoms and cell cultures
An experimental method for remitted photon path length measurements in scattering media has been developed and tested on human skin and skin neoplasms, skin phantoms and cell cultures. The photon time-of-flight (PTOF) measurement method was used in this study, where the photon travel time was converted into path length. Remitted light signals were obtained using a picosecond broadband laser and a set of narrowband interference filters in spectral rang 520 – 760 nm. Five different distances of 1, 8, 12, 16 and 20 mm between the source and detector fibers were used. Measurements were performed at different wavelengths and distance combinations; they were taken from human skin and skin malform…