Final answer:
The radiographic technique where the part and the film/IP/detector stay stationary while the tube moves, or the part and film/IP/detector move in unison while the tube remains stationary, is known as Computed Tomography (CT).
Step-by-step explanation:
The radiographic technique where the position of the film/image plate (IP)/detector and the part of the body being imaged must remain stationary relative to one another, while the tube can move, is known as Computed Tomography (CT). In CT, the patient lies on a motorized platform and the X-ray tube rotates around them, taking a series of images from different angles. These images are analyzed by a computer to produce cross-sectional views or "slices" of the body. This technique provides three-dimensional images and detailed information about the structures within the body, utilizing the differences in X-ray absorption to create the image.
Another related but separate technique is single-photon-emission computed tomography (SPECT), which also utilizes a circular array of detectors that may be stationary or rotated. However, SPECT involves the use of radiopharmaceuticals and nuclear activity to form the images, with generally lower spatial resolution but good contrast.