Neonatal magnification radiography using standard-focus x-ray tubes.

Radiographic examination of the chests of premature newborn infants is complicated by the small size and poor object contrast of the structures to be evaluated. Magnification radiography can improve image quality significantly in this situation. Unfortunately, high-quality magnification radiography requires dedicated microfocus equipment that is not available in most neonatal intensive care units. The use of standard-focus x-ray tubes (up to 1 mm focal spot size) for moderate magnification radiography (1.5 times) by using the anode side of the x-ray field of the standard mobile x-ray unit is proposed. In addition to the cost advantage of using existing standard mobile x-ray equipment, the high tube current allows for short exposure times and long target-film distances. This reduces most motion unsharpness and allows for a large air gap that results in improved image contrast. Although focal spot size at the anode side of the field is smaller in only one dimension, the magnification radiographs are superior to those obtained using the central part of the x-ray beam and superior to standard contact radiographs using the same equipment. Improvement in image quality is due primarily to decreased noise and improved contrast in the magnified image.