Subtraction Technique

**Definition:** Combination or superimposition of two images for demonstrating differences between them (e.g., radiograph with contrast vs. one without, radionuclide images using different radionuclides, radiograph vs. radionuclide image) and in the preparation of audiovisual materials (e.g., offsetting identical images, coloring of vessels in angiograms).

**Tree numbers:** - E01.370.350.760

**Synonyms:** - Subtraction Technic