Identification of optical parameters of the cerebrospinal fluid and tumor fluid during laser photodynamic therapy of malignant intracerebral tumors

Abstract

A technique for treating cerebral malignant tumors using laser photodynamic therapy (PDT) is briefly described by the authors. The described technique includes a direct photosensitizer’s injection into a bed of removed tumours and its further postoperative irradiation. The authors discuss the problem of partial loss of laser light on its way to target tissues. This loss is caused by light dispersion and absorption in protein and blood additional particles which are present in the liquid accumulating in the bed of the resected tumor. In experiment, there have been analyzed relations between the lost light power and concentrations of protein and erythrocytes in the cerebrospinal fluid and in the cystic tumor liquid. The authors propose techniques for analytical and graphic estimation of light power corrections which could compensate light losses.