Non-invasive method for tissue response detection to ionizing radiation treatment

Radiation therapy is a well know cancer treatment method. Even though it is widely accepted that the individual's response to radiation is heterogeneous, current practices are based on almost uniform fraction doses. Late radiation effects cannot be predicted and the treatment has a very weak feedback. A method to quantify the tissue response to radiation would radically alter conventional treatment norms by allowing the radiation oncologist to tailor treatment to the individual in an unprecedented manner. We show that the /spl alpha/ and /spl beta/ dielectric dispersions can be related to radiation induced changes in both extracellular matrix and cell membrane state. The /spl alpha/ dispersion is mainly due to the extracellular fluid, but counterion polarization, membrane conductance and the charging of intracellular membrane bound organelles also contribute. The /spl beta/ dispersion occurs at low radiofrequencies, arising principally from the capacitive charging of cellular membranes in tissues. We present results obtained in irradiated excised mice organs.