Noninvasive evaluation of absolute fluorochrom concentration in various tissues in vivo by means of standard samples with modeled optical properties

摘要

Abstract: The problem of accurate determination of fluorochrome concentration in tissues from fluorescent spectra is the most important one in the spectroscopy of biological objects. Especially it is significant for the application of photodynamic therapy (PDT) when the concentration of photosensitizer (PS) in tumor and surrounding normal tissues should be known so that one could employ the appropriate treatment tactics (irradiation dose and time). It is also desirable that the screening depth be the same order as the light penetration depth used for treatment. To solve these problems we have prepared the standard samples with the optical properties close to that of tissues under investigation. The various fractions of sulphanated aluminum phtalocyanine (Al-Pc) have been used as photosensitizers. The samples with various concentration of Al-Pc have been prepared and the intensity of fluorescence excited by He-Ne laser, as well as the laser scattered line, have been measured to give a calibration curve. !9