PHOTOTHERMAL EFFECTS ON MURINE MAMMARY-TUMORS USING INDOCYANINE GREENAND AN 808-NM DIODE-LASER - AN IN-VIVO EFFICACY STUDY

Murine mammary tumors were treated using indocyanine green and an 808 nm diode laser, and the in vivo chromophore-enhanced photothermal effe cts on the tumor burden and on tumor rat survival were investigated. T he power of the laser was selected in the range of 5-10 W, and irradia tion duration 3-5 min. One percent aqueous indocyanine green solution in a volume of 100-200 mu l was administered in situ, either acutely o r 24 h prior to the treatment. The photothermal interaction was appare nt under all our treatment conditions with a well-defined spatial cont ainment in this study and the tumor growth was slowed after treatment. The post-treatment observation showed tumor recurrence and metastasis ; no long-term survival was achieved with the single application of la ser in conjunction with indocyanine green. Our results pose a question on the efficacy of the photothermal interaction even though tumor cel l destruction can be achieved in a large and controlled scale. However , this highly selective photothermal impact on the tumor tissue did su ggest that this method be applied repeatedly to be more effective and be used as the precursor of other modalities, such as chemotherapy, ra diation therapy, immunotherapy, and surgery.