Phantoms of fingers with various tones of skin for LLLT dosimetry

摘要

Due to the great number of new clinical applications of Low-Level-Laser-Therapy (LLLT), the development of precise, stable and low cost solid phantoms of skin, fat, muscle and bone becomes extremely important. The aim is to find the best combination of matrix, absorber and scatterers, which simulate skin, fat, muscle and bone tissues to build LLLT phantoms. Eight cylindrical phantoms simulating various human fingers were constructed and tested. Matrixes of polyester resins and paraffin were used with various concentrations of dyes and scatterers (Al_(2)O_(3) nanoparticles) to adjust the optical parameters. A CCD camera was used to obtain transmission and scattering images of the phantoms, and of swine tissues and volunteer's fingers illuminated by lasers (diode 635 and 820 nm, and HeNe, 633 nm). The light fluence transmitted through the sample form Gaussian shaped profiles. Light scattered at 90 degrees shows an intensity profile with a steep growth followed by an exponential attenuation. The comparison of these two kinds of profiles for phantoms and swine tissue was used to evaluate the concentrations that better simulate different kinds of tissues. The outcomes of this study point to a reliable tool to aid clinicians with LLLT dosimetry.