Considerations for standard chest radiography: the long film-focus distance technique.

The possibility of using long film-focus distance radiography as a new screening method for lung cancer diagnosis was investigated. Long-film focus distance radiography produced exceptionally superior image sharpness suitable for use as clinical photographs, at a distance of about FFD (Film-Focus Distance) 20 m. The effective energy was increased by narrowing the radiation spectrum via an air-filter effect, which may prove useful in reducing radiation exposure dosage. Questionnaire results indicate good visualization of cardiac posterior and trachea shadow regions in the diaphragm. Further study is required regarding methods for stabilizing patient position and synchronization with heart beat and respiration to improve reproducibility.