What occurs inside the tube when high magnification mode is utilized?

When high magnification mode is activated in fluoroscopy, only part of the input image intensifier (II) is used. This is primarily because the system selects a smaller portion of the input phosphor to enhance spatial resolution and image detail. By concentrating on a smaller area, the magnified image retains better clarity and minimizes the amount of scattered light that could compromise image quality.

In high magnification mode, the main objective is to improve image resolution for specific anatomical areas. Using only a portion of the input phosphor means that the system can generate a larger image of the area of interest while maintaining high detail and contrast. This is particularly useful in diagnostic procedures where precise visuals of smaller structures are necessary.

In contrast, utilizing all sections of the input image intensifier does not occur in high magnification mode since that would result in a wider field of view with less detail. Similarly, the other options involving the output phosphor do not accurately reflect the functioning mechanism of magnification in this context, as the output phosphor is related to the intensified image produced after the input phosphor processing. The focus remains on the specific manipulation of the input side in high magnification mode to achieve the best possible image quality for detailed examination.