If you mean does it affect our genetic makeup, no. It will kill some cells, which I suppose could be seen as affecting the DNA of those cells a bit. Others will be damaged, but they recover or get replaced, mostly anyway
Radiotherapy and Xray radiation can produce a variety of lesions in DNA. It can break the strands, and an Xray dose of 1Gy produces about 1000 single strand breaks.
Double strand breaks in DNA have shown a direct porportionality to radiation dosage.
After treatment for breast cancer, for example, it's been noted that repair is possible, and not always fatal to the DNA. background radiation is different, as our DNA's learnt to cope with this.
Yes Wildwood that's what i thought. What i'm trying to find out is,i know of a person who was convicted of a crime he did not commit. The strong suspect they had whose blood group matched and was quite rare got off with it as his DNA didn't match. He'd had 'radiotheropy' treatment for cancer.