Radiation causes damage by generating hydroxyl free radicals (Pathoma chapter 3 table). Therefore, if something minimizes the damage of radiation, it has to inhibit free radical formation.
therapeutic ionizing radiation(gamma rays,x-rays); -DNA double-strand breakage -Free radical formation
Free radicals damage cells via membrane lipid peroxidation, protein modification, DNA breakage. Initiated via radiation exposure (eg, cancer therapy), metabolism of drugs (phase I), redox reactions, nitric oxide (eg, inflammation), transition metals, WBC (eg, neutrophils, macrophages) oxidative burst.
And just incase you were as curious as I am and wanted to know what tautomerism is.... A tautomer is an isomer , and isomers are compounds that have the same number of atoms of the same element but different structural arrangemennts
A NOTE TO SELF : DO NOT PICK THIS ANSWER IN THE EXAM
submitted by โmadojo(212)
The two main types of radiation type are ionizing and nonionizing.
The ionizing would be the radiotherapy and non-iodizing is from the sun.
Ionizing = free radical formation non ionizing (UVB) = DNA damage by formation of pyrimidine dimers