The rise in the population of cancer survivors has led to a better understanding of the effects of RT to treat cancer patients . A significant portion of cancer survivors are patients with a history of childhood cancer. According to the American Cancer Society (ACS) the 5-year survival rate for childhood cancer patients is now over 80%. However, exposure to radiation treatment can lead to the occurrence of secondary primary cancers (SPCs) in the future. An analysis of thyroid cancer in childhood cancer survivors showed that the relative risk of thyroid cancer in these patients increased linearly with the dose of radiation for treatment through 10 Gy . The relative risk of thyroid cancer post RT was lowered at high treatment doses. Another study looking at chest RT to treat childhood cancers showed an increased risk of breast cancer in these patients . Especially treatment involving whole-lung irradiation increased this risk. This shows the importance of localized RT to reduce the risk of SPCs. The need for improvement in RT techniques that spare normal tissue is also highlighted by the incidence of metachronous cancers (multiple primary cancers developing at intervals) in adults. The incidence of secondary primary lung tumors increased by a stark 8.5% per Gy in women who had undergone RT for breast cancer . An analysis of prostate cancer patients also told a similar story. Patients with prostate cancer undergoing RT had an increased overall risk of developing hematologic, liver, esophageal, and urinary bladder cancers . Certainly, the induction of DNA damage by RT is an important factor towards the prediction of SPCs. Recent studies for example show that simulated radiation-induced persistent telomere-associated DNA damage foci can be used to predict excess relative risk of developing secondary leukemia after fractionated radiotherapy . In general, the incidence of secondary malignant neoplasms (SMN) depends on several factors like patient’s lifestyle, genetic susceptibility, DNA repair efficiency and radiosensitivity of the patient or specific organ .