Densitometric studies on the shadows of paranasal sinuses in sagittal projection

In taking a X-ray photography of the head in sagittal projection, it is most important that the center of the X-ray beam passes exactly through the median-sagittal line. If the subject turns his head either to the right or to the left, the paranasal sinuses become denser on one side, leading to erroneous interpretation of the radiographic findings. In order to eliminate such a misinterpretations, studies were carried out on the following: 1) Application of a standard of what degree of head turning to either side would start to influence judgment of the shadow of the paranasal sinuses. 2. Application of a standard to judge whether they are projected to an exact center position or not in actually diagnosing the X-ray films.