Cherenkov light is created in clinical applications involving high-energy radiation such as in radiation therapy. Due to improvements in camera sensitivity, we are now able to detect and measure Cherenkov light created during radiation therapy using linear accelerators (linacs). However, no method currently exists for using Cherenkov light to estimate the absolute radiation dose delivered to irradiated tissues. We have developed a technique to perform dosimetry with images of Cherenkov emission using deconvolution imaging techniques. The deconvolution technique relies upon the Cherenkov Scatter Function (CSF), a function that describes the scattering of Cherenkov light as it is generated by the treatment photons and propagated through tissue to the surface of the skin. In this study, the CSF was generated through Monte Carlo for 6 MV, 10 MV, and 18 MV photon beams in light, medium, dark skin, and optical tissue phantom materials. Functional dependence of on incident treatment beam angle is shown. The CSFs generated are parameterized using a double-Gaussian distribution and fit coefficients are given. Basic formulation of the deconvolution imaging equation is given to show the relationship of the CSF to x-ray beam flux.
|