Final Answer:
Computed radiography uses the middle part of the histogram to determine the exposure indicator number.
Step-by-step explanation:
In computed radiography (CR), the histogram is a graphical representation of the distribution of pixel values in the digital image. It reflects the exposure received by the image receptor during the radiographic process. The exposure indicator number is determined by analyzing the middle part of the histogram, specifically the central region where the majority of pixel values lie. This area is crucial for assessing the overall exposure and image quality.
By focusing on the middle portion of the histogram, CR systems can calculate an exposure indicator number that provides valuable information about the radiation exposure received by the image receptor. This indicator aids radiographers in optimizing exposure settings, ensuring diagnostic image quality while minimizing radiation dose to patients.