Doi K, Rossmann K, Duda E E
Radiology. 1977 Aug;124(2):395-401. doi: 10.1148/124.2.395.
A new method of stereoscopic cerebral angiography has been developed which employs 2X radiographic magnification. In order to obtain the same depth perception in the object as with conventional contact stereoscopic angiography, one can made the x-ray exposures at two focal spot positions which are separated by only 1 inch (2.5 cm), whereas the contact technique requires a separation of 4 inches (10 cm). The smaller distance is possible because, with 2X magnification, the transverse detail in the object is magnified by a factor of two, but the longitudinal detail, which is related to the stereo effect, is magnified by a factor of four, due to the longitudinal magnification effect. The small focal spot separation results in advantages such as improved stereoscopic image detail, better image quality, and low radiation exposure to the patient.
一种采用2倍X射线放大的立体脑血管造影新方法已经研发出来。为了在物体中获得与传统接触式立体血管造影相同的深度感知，可以在仅相隔1英寸（2.5厘米）的两个焦点位置进行X射线曝光，而接触技术需要相隔4英寸（10厘米）。较小的距离是可行的，因为在2倍放大的情况下，物体中的横向细节被放大了两倍，但与立体效果相关的纵向细节由于纵向放大效应而被放大了四倍。小焦点间距带来了诸如改善立体图像细节、提高图像质量以及减少患者辐射暴露等优点。
