Laser blood flowmetry in malignant tumors during photodynamic therapy: an experimental study

摘要

Abstract: Laser blood flow measurements were performed on the tumor surface of 45 oral cancers growing on the shank of nude mice to detect changes in microcirculation (mc) during and up to 6 hours after PDT. PDT was performed in 27 animals (9.9 mg HPD/kg b.w. 24 hours pre radiation; 150 mW/cm$+2$/, 200 J/cm$+2$/), 17 mice received only the photosensitizer without laser radiation. Simultaneously skin mc in the contralateral leg was measured to detect systemically caused changes in mc. Specimens of the tumor regions were taken two days later and analyzed histologically. With regard to our tumor model and the PDT conditions our results favor a mainly direct effect of PDT on the tumor cells rather than tumor necrosis caused by decreased mc. Although the method of laser doppler flowmetry (LDF) is very sensitive to all kinds of faults and blood flow can't be quantified in absolute units, changes of mc on the tumor surface are sufficient to be detected. !9