The effectiveness of radiation therapy can be enhanced by understanding the fragmentation mech- anisms of iodine-doped DNA oligonucleotide under tender X-rays, as explored experimentally and computationally in our study. By selectively targeting iodine atoms above their L-edge ionization energies, we observed a significant increase in the production of fragments critical to DNA back- bone breakage, particularly within mass ranges associated with phosphate and sugar groups. The mass spectroscopy experiments demonstrated that iodine-doped DNA oligonucleotides undergo in- tense fragmentation at long distances from the initial photoactivation site. Born-Oppenheimer based molecular dynamics simulations confirmed the generation of numerous small, fragments, includ- ing reactive oxygen species, which are pivotal in enhancing the radiation damage. These findings highlight the effectiveness of iodine doping in amplifying DNA damage in radiotherapy via iodine photoactivation, thereby improving the potential for targeted cancer treatment.
