Portable Laser Spectrofluorimeter System for in Vivo Human Tissue Fluorescence Studies

Abstract

A compact, portable spectrofluorimeter which measures broad-band fluorophores with high sensitivity is described. This instrument is specifically designed for acquisition of human tissue autofluorescence spectra in vivo. Pulsed excitation laser light at 337 nm and in the 370–700 nm wavelength range is provided, and the resulting fluorescence can be measured with 10-nm resolution. The system produces single-pulse spectra in human artery wall tissues with a signal-to-noise ratio of 100:1. An optically shielded fiber-optic probe for light delivery and collection permits calibrated intensity information to be obtained.

Observation of Periodic Fine Structure in Reflectance from Biological Tissue: A New Technique for Measuring Nuclear Size Distribution

“…In the experiments, an optical fiber probe was used to deliver white light from a xenon arc flashlamp to the samples and collect the return reflectance signal. The probe tip, 1 mm in diameter, consisted of a central delivery fiber surrounded by six collection fibers (200 mm core fused silica, NA 0.22, V i V c pNA 2 ), all of which were covered with a 1 mm thick quartz optical shield [14]. Figures 1(a) and 1(b) show the normalized reflectance R͑l͒͞R͑l͒ from normal and T84 tumor cell samples, respectively.…”

Complete parameterization of temporally and spectrally resolved laser induced fluorescence data with applications in bio-photonics

“…Several successful applications based on measurements of the dominating chromophores (such as oxy-and de-oxy-hemoglobin) were presented [3,4] and, related to these techniques, a discipline studying light transport in highly scattering media was established [5][6][7][8][9][10][11][12]. Biomedical fluorescence was also widely studied, including both tissue autofluorescence [1,[13][14][15][16][17][18] and fluorescent sensitizers such as protoporphyrin nine, PpIX [19,20]. Since fluorescence is a secondary effect of absorption, the measured intensity of inelastic (fluorescence) photons is weaker by orders of magnitude than that of elastic (scattered) photons.…”

Calibration standards for multicenter clinical trials of fluorescence spectroscopy for in vivo diagnosis

“…The calibrated FastEEM data should become device independent and should be able to be combined for analysis with data acquired with other calibrated optical devices. 8,[16][17][18][19] In this study, two generations of the FastEEM system were tested clinically at three different sites: the University of Texas ͑UT͒ M.D. Anderson Cancer Center in Houston ͑FastEEM2͒; the Lyndon B. Johnson Harris County Hospital District in Houston, Texas ͑FastEEM2͒; and the British Columbia Cancer Agency ͑BCCA͒ in Vancouver, Canada ͑FastEEM3͒.…”

“…Fluorescence-and reflectance-based point spectroscopy and imaging systems were successfully applied by many groups in many organ sites for noninvasive probing of tissue properties. [17][18][19][20][21][22][23][24][25][26][27] While calibration standards are widely used for preprocessing of the acquired data, methodologies for instrument characterization, validation, and radiometric traceability lack standardization. The National Institute of Standards and Technology ͑NIST͒ has recognized that a major factor inhibiting rapid growth is the inability to make comparable fluorescence intensity measurements across laboratories.…”