What term describes the introduction of radioactive materials into the body for single-plane display of images?

The correct answer is "Planar imaging." This term specifically refers to a type of imaging where radioactive materials are introduced into the body, allowing for the capture of images in a two-dimensional format, typically at a single angle or plane. This method is often used in nuclear medicine procedures, where radiopharmaceuticals are administered to visualize certain organs or tissues within the body.

Other methods, such as 3D imaging, refer to techniques that produce three-dimensional visualizations, often requiring multiple images from various angles, which is not the focus in planar imaging. CT imaging involves the use of X-rays to create cross-sectional images of the body, which is distinctly different from the use of radioactive materials. Virtual imaging typically employs computer graphics to simulate or analyze data rather than capturing real-time images through radioactive sources. Thus, planar imaging accurately captures the essence of the question about using radioactive materials for imaging in a single-plane format.