| Popis: |
Due to the fact that, absorb light efficiently, dyes and pigments (photosensitized) are characterized by their ability to absorb visible light, and to participate in photochemical reactions. These dyes are used in medicine in the recommended dose for use in photodynamic therapy (PDT). There are lasers that can work with most of the phototherapeutic agents and are capable of providing light of considerable power with precision on the injured tissue. The use of light emitting diodes (LEDs) have become feasible, reducing the cost of the procedures. The Chemistry Dosimetry Laboratory CRCN / CNEN has worked with some dye use in phototherapy treatments, including: methylene blue, malachite green and toluidine blue. Samples are prepared with a volume of 2.6 mL of the Fricke solution modified by the addition of dyes and ethanol, that was transferred into test tubes and they were irradiated with light: red, blue and green LED array (12-19). This procedure was realized by 24, 48, 72 and 96 h, using test tubes located in the acrylic surface simulator 110 mm x 110 mm x 80 mm perpendicular to the central axis of the radiation beam at a distance of 6.5 cm from the light source. Obtaining excellent correlations (above 0.97) showing proportionality between irradiation time and optical density measured. Suggests that the dosimeter can be applied to perform a quality control in photodynamic therapy. However, others experiments, should be performed before a wide application of this technique. |
