Thermal damage assessment of blood vessels in a hamster skin flap model by fluorescence measurement of a liposome-dye system.
OBJECTIVE
The present study was undertaken to evaluate the feasibility of thermal damage assessment of blood vessels by using laser-induced release of liposome-encapsulated dye.


METHODS
Experiments were performed in a hamster skin flap model. Laser irradiation was achieved with a 300 microm fiber connected to a 805 nm diode laser (power = 0.8W, spot diameter = 1.3 mm and pulse exposure time lasting from 1 to 6 s) after potentiation using a specific indocyanine green (ICG) formulation (water and oil emulsion). Liposomes-encapsulated carboxyfluorescein were prepared by the sonication procedure. Carboxyfluorescein (5,6-CF) was loaded at high concentration (100 mM) in order to quench its fluorescence. The measurements were performed after i.v. injection of DSPC liposomes (1.5 ml) and lasted 40 min. Fluorescence emission was measured with an ultra high sensitivity intensified camera.


RESULTS
Three different shapes of fluorescent spots were identified depending on target (blood vessel or skin) and energy deposition in tissue: (i) intravascular fluorescence, (ii) transient low fluorescence circular spot, and (iii) persistent high intense fluorescence spot. These images are correlated with histological data.


CONCLUSIONS
Real-time fluorescence imaging seems to be a good tool to estimate in a non-invasive manner the thermal damage induced by a diode laser combined with ICG potentiation.
Mordon
S
S
Inserm U279, Pavillon Vancostenobel, CHU, Lille, France.
Desmettre
T
T
Devoisselle
J M
JM
Soulie
S
S
D000818:Animals; D001808:Blood Vessels / Q000473:pathology*; D006224:Cricetinae; D004337:Drug Carriers; D005452:Fluoresceins / Q000008:administration & dosage*; D005453:Fluorescence; D007208:Indocyanine Green; D017075:Laser Coagulation / Q000009:adverse effects*; D008081:Liposomes; D008297:Male; D012867:Skin / Q000098:blood supply* / Q000473:pathology; D013524:Surgical Flaps
D004337:Drug Carriers; D005452:Fluoresceins; D008081:Liposomes; C024098:6-carboxyfluorescein; D007208:Indocyanine Green