BREATH ETHANE GENERATION DURING CLINICAL TOTAL-BODY IRRADIATION AS A MARKER OF OXYGEN-FREE-RADICAL-MEDIATED LIPID-PEROXIDATION - A CASE-STUDY

Total body irradiation (TBI) is used therapeutically for treatment of leukemias and other malignancies of the hemopoietic system. Ionizing r adiation produces oxygen free radicals that contribute to cytotoxicity . Breath collected from one patient undergoing therapeutic TBI showed measurable changes in levels of ethane during treatment. Breath ethane is a marker of lipid peroxidation of n-3 fatty acids. The TBI treatme nt involved 4 days of irradiation. The largest changes in breath ethan e occurred on Day 2. The increased levels of breath ethane on Day 2 we re correlated to clinical manifestations of toxicity. The correlation of the onset of gastrointestinal side effects with higher levels of br eath ethane suggests that breath ethane may be a clinically useful mea sure of the toxicity of various TBI fractionation treatment protocols currently in use at different medical centers. The levels of breath et hane on the other days of treatment were lower, suggesting that the ox idative-antioxidative balance of the patient may be important in prote ction against free radical mediated injury. These results for a single patient suggest that breath ethane may be a promising approach to elu cidate the role of antioxidants in clinical TBI and should be extended for verification to a larger volunteer patient population.