Can Radiation therapy be dangerous

The answer is yes.
Delayed necrosis of the spinal cord and brain is a well recognized sequelae of radiation therapy for tumours in these regions and in the thorax and neck. The peripheral nerves are more resistant to this adverse affect.Transient myelopathy: The “early” type of radiation myelopathy (appearing 3 to 6 months after radiotherapy) is characterized mainly by paresthesias in the extremities. The paresthesias may be evoked or exacerbated by neck flexion (Lhermitte symptom). Delayed Progressive Radiation Myelopathy: This, the most dreaded complication of radiation therapy, is a progressive myelopathy that follows, after the characteristic latent period, the irradiation of malignant tissues in the vicinity of the spinal cord. The incidence of this complication is difficult to determine because many patients die of their malignant disease before the cord lesion matures, but it is estimated to be between 2 and 3 percent .