| Abstract: | ![]()
The inability to image the 3rd dimension has meant a loss of valuable information, e.g., examination of an IUD in the uterine cavity. Whatever plane is examined longitudinal, transverse, or oblique the image always is a 2-dimensional tomograph producing either bars or dots. Even when the transducer lies perpendicular to the long axis of the IUD, the IUD cannot be visualized as a whole because the 1st bar produces an acoustic shadow that covers all the other bars. A technique now exists for obtaining the 3rd dimension by moving a linear array transducer over the area to be examined, which produces an endless number of images on the screen. Since the commonly used real-time scanners are not equipped with storage capacity, these images immediately fade away. This problem can be resolved by using a Polaroid camera as a storage device. The shutter is opened for the longest exposure possible, i.e., 1 second, while the diaphragm is closed. During this 1 second of exposure, the linear array transducer is "swept" over the area for examination using the compound movement technique. A second is a relatively long time, but some training is necessary before the operator can easily perform the "sweep." If the whole movement cannot be carried out in 1 second, an additional second can be used. This will rusult in a slightly overexposed picture, but these are sometimes even easier to interpret. It is important that the area be well lubricated, and the patient stop breathing for the duration of the scan. The equipment used in the study included a Picker 2000 and a Unirad real-time scanner. Both scanners were handled in the same way, and the same technique was used. Different kinds of IUDs were visualized and recorded. |
