Radiation injury: imaging findings in the chest, abdomen and pelvis after therapeutic radiation.

Radiation may be used as adjuvant or primary therapy in a variety of tumors in the chest, abdomen and pelvis. Therapeutic radiation affects not only malignant tumors but also surrounding normal tissues. The risk of injury depends on the size, number and frequency of radiation fractions, volume of irradiated tissue, duration of treatment, and method of radiation delivery. Concomitant chemotherapy can act synergistically to produce injury. Other predisposing factors include infection, prior surgery and chronic illness like hypertension, diabetes mellitus and atherosclerosis. Radiation changes vary, based on the target organ and the time from completion of therapy. While most serious complications related to radiotherapy are relatively uncommon, given the number of patients that are treated and the relatively long latency period for development of radiation changes, follow-up imaging studies frequently have findings that should be recognized as radiation related. Familiarity with the spectrum of imaging findings after radiation injury permits differentiation from other etiologies such as recurrent malignancy. The following will discuss imaging findings that may be seen during imaging surveillance in patients with malignancy affecting the chest, abdomen and pelvis.