How radiation from a CT scan should be considered in patient care depends upon the circumstances in which the test is conducted. Ionizing radiation, the adverse health effects from which are cumulative, should be minimized but used when appropriate.
Chest CT scans are used primarily for diagnostic purposes but also for monitoring disease and screening for asymptomatic disease. The challenge regarding radiation risks is to address the purpose of the CT scan. In evaluating pulmonary embolism, chest injuries, and other life-threatening conditions, radiation exposure is a trivial factor. In evaluating hemoptysis, chronic shortness of breath, and symptoms that may reflect malignancies, radiation exposure needs to yield to obtaining important diagnostic information. In screening for lung cancer, however, radiation exposure should be considered in evaluating benefits and risks of the CT scan.