Room: Stars at Night Ballroom 4
Purpose: Cherenkov imaging has been used to extract and analyze dose distribution in radiation therapies, including TSET, based on the linear relationship between the Cherenkov light intensity and dose deposition on the same materials. However, the tissue optical property is different for different patients. The same dose can generate different amount of Cherenkov intensity from different patientsâ€™ bodies. This study focuses on the dependence of the ratio of Cherenkov intensity to dose on tissue optical property. The conversion ratios are to that measured in different patients.
Methods: Tissue phantoms are created with different tissue optical properties. The optical properties, which are absorption (Âµa) and scattering (Âµâ€™s) coefficient, are measured for these phantoms, and the values of diffuse reflectance are calculated. The phantoms are placed in the center of the TSET patientâ€™s location and irradiated with electron beams with different amounts of dose. The ratios of Cherenkov intensity to dose were measured for each phantom and compared with the values of diffuse reflectance. Monte Carlo simulation was performed and compared with the measurements.
Results: The ratio of Cherenkov intensity to dose, Î±, is comparable to results based on Monte Carlo simulation and can be fitted to a linear function of Rd. Thus, the Cherenkov signal can be converted to dose for different patients through the measurement of tissue optical property of their skin.
Conclusion: The study shows a dependence of the ratio of Cherenkov intensity to dose as a function of the tissue optical properties.