Nonsegmental ventilation-perfusion scintigraphy mismatch after radiation therapy

Purpose: This report illustrates the utility of ventilation-perfusion scint igraphy in differentiating radiation pneumonitis from other causes of dyspn ea, including pulmonary embolism, heart failure, obstructive tumor, and chr onic obstructive pulmonary disease. Methods and Results: A nonsegmental mismatched perfusion abnormality, which exactly conformed to a radiation port, was diagnostic of radiation pneumon itis. Conclusion: In patients with lung tumors presenting with dyspnea, ventilati on-perfusion scintigraphy may be useful in diagnosing radiation pneumonitis and effectively excluding other causes of dyspnea.