Currently the radiographic determination of the benign or malignant nature of solitary pulmonary nodules relies on growth characteristics determined by comparison radiographs or the detection of calcification in the nodule with either low-peak kilovoltage fluoroscopy or CT of the chest. An alternative approach is analysis of the optical densities within the nodules by means of digital radiography. Two techniques have been described: histogram analysis of chest radiographs digitized with a laser scanner and dual-energy digital radiography. Although both techniques remain experimental, they offer a potential advantage over CT in that a single radiographic exposure is sufficient, thus decreasing the radiation dose to the patient and providing the patient with a less complex work-up.