Design of a dynamic dermofluorometer for the measurement of skin perfusion

摘要

The design of a two-channel dynamic dermofluorometer to monitor skin perfusion using a fluorescent dye is reported in this paper. The hardware of this system consists of an optical module (flash lamp, optical fibers, dichroic beamsplitters, and optical wavelength filters), an electrical module, and a Macintosh computer. This system is controlled by software written using LabVIEW and MPW C running with the support of a Lab-NB multifunction board. This instrument is capable of real-time data acquisition, curve fitting, and display. Two fluorescent dyes, carboxyfluorescein and sodium fluorescein, were used in prelimiary animal studies (6 rats). Each dye was injected intravenously and its signal collected by an optical fiber bundle (diameter 3.2 mm) placed on the skin. The washin time constants were similar for both dyes (approximately 5 min.), but sodium fluorescein exhibited a much slower clearance time constant (110 min. vs. 65 min.). The instrument was tested on four normal human volunteers. The washin time constant of sodium fluorescein (1 mg/kg) for two skin sites on the forearm was measured on each subject (average 2-3 min.). These results demonstrate the potential of this instrument for performing dynamic fluorescence measurements. Future studies on diabetic patients are planned at the Danville, Illinois VA Medical Center.