Fluorescent imaging in a glioma model in vivo.
OBJECTIVE
Nile blue dyes have been shown to have affinity for tumor tissue as compared to surrounding normal tissue and to be relatively non-toxic. We have employed EtNBA, a lipophilic, fluorescent benzophenoxazine dye, in a murine model to image subcutaneous and intracranial U-87 glioma implants.


METHODS
The imaging system used to detect fluorescence consists of a SIT video camera fitted with a zoom microscope-magnifying lens. The tumor was illuminated with a 632.8-nm diffuse beam from a helium-neon laser. The video image was processed using a Sony image processor to give real-time pseudocolor and enhanced black and white images.


RESULTS
Following subcutaneous injection of the dye at doses of 2.5-5.0 mg/kg bw, we observed a gradual increase of the fluorescent signal from the tumor which peaked 1-3 hours post-injection with variable selectivity (typically 4:1) for tumor to normal surrounding tissues permitting the clear demarcation of the tumor.


CONCLUSIONS
The present in vivo study demonstrates that EtNBA is a safe and effective photodiagnostic agent, able to demarcate U87-MG solid tumors in mice on a real-time basis at a concentration of 2.5-5.0 mg/kg 1-3 hours after administration.
Nikas
D C
DC
Center for Neurosurgical Sciences, Brain Tumor Research Center, Brigham and Women's Hospital, Children's Hospital and Dana Farber Cancer Institute; Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA. dnikas@rics.bwh.harvard.edu
Foley
J W
JW
Black
P M
PM
D000818:Animals; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000008:administration & dosage; D005910:Glioma / Q000175:diagnosis* / Q000473:pathology; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D010078:Oxazines / Q000008:administration & dosage; D013997:Time Factors
D005456:Fluorescent Dyes; D010078:Oxazines; C081283:5-ethylamino-9- diethylaminobenzo(a)phenoxazinium