[Imaging of side effects after radiation therapy].

backgroundPeritumoral normal tissue is inevitably also irradiated during radiotherapy, depending on the location and size of the target volume as well as the cumulative dose. Depending on the temporal course after irradiation acute, subacute, and chronic alterations are described in co-irradiated normal tissue that can be detected by imaging. Radiation damage can be transient or persistent.

objectiveThis article gives an overview of the most important signs of radiation-induced radiogenic alterations to tissue in various organ systems.

findingsFrequent radiation-induced tissue alterations found by imaging are pneumonitis, disturbance of the blood-brain barrier, radionecrosis of brain tissue, radiogenic liver damage, mucositis, colitis, osteitis, osteoradionecrosis and myositis. The combination with systemic chemotherapy or immunotherapy can increase the severity of radiogenic reactions of normal tissue. RECOMMENDATIONS FOR AFTERCARE: The most important differential diagnosis for radiogenic alterations to normal tissue is post-therapeutic tumor recurrence. Besides typical latency periods, location and matching with the radiation field are important differentiation criteria, depending on the tumor biology and the radiation technique. The follow-up schedule should follow the current guidelines and the clinical condition of the patient should be additionally considered. The radiologist needs to be familiar with the typical imaging morphology of radiogenic tissue changes to avoid false interpretation during follow-up investigations.