Optimization and spectrophotometric comparisons of radiochromic dye (2,3,5-triphenyl-2-H-tetrazolium chloride) in gelatin and agar models: gamma and electron beam irradiations
Date of Award
Honors College Theses
Dr. Diola Bagayoko
Dr. Rogers J. Newman
Dr. Beverly Wade
After irradiation, the colorless radiochromic dye, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), changes to red triphenyl formazan pigment, and the distribution of absorbed dose in the tissue-equivalent gelatin and agar media can be studied. Using solutions 8% by weight gelatin and 8% by weight agar, both with 3 mM citric acid as buffer and 4 mM concentration of dye, the radiation-induced absorbency of a sample slowly decreased with increasing wavelength. In the gel, TTC is very light sensitive, and 7 days after irradiation, becomes less stable. The samples were irradicated by gamma and electron beam. Nine different doses were used for the 60Co gamma source. Each cylindrical sample of a different dose was sliced one day after irradiation and analyzed by UV-V is spectrophotometry. Absorption maxima were obtained at wavelengths of 520 nm and 570 nm. Using accelerated electrons at an energy of 25 MeV generated by MIRF (Medical-Industrial Radiation Facility), the gelatin samples were irradiated at nine different exposure times. In previous studies of this model, only the gelatin was used. Now, some comparisons of the radiochromic dyes in different gel matrices of gelatin and agar at different concentrations to optimize dose sensitivity have been completed. Also, some comparisons of the gelatin samples irradiated in borosilicate glass containers at different doses were performed. Along with studies of the concentration of the gels comparing 8% by weight gelatin to 10% by weight gelatin. After analysis, the gelatin samples were observed to be the better gel media, the 10% gelatin samples were firmer and easier to handle, and the borosilicate glass containers were logistically advantageous for the gelatin samples. The dose response will be observed with both gamma and electron beam irradiation to determine the amount of color change with a spectrophotometer. Studying the dose distribution of the irradiation gelatin and agar tissue models will be significant for the future studies of radiation therapy to estimate dose distribution within patient.
Frances, Lakindra P., "Optimization and spectrophotometric comparisons of radiochromic dye (2,3,5-triphenyl-2-H-tetrazolium chloride) in gelatin and agar models: gamma and electron beam irradiations" (1997). Electronic Dissertations and Theses. 48.