What happens to the radiation field at the tabletop when the image intensifier is moved closer to the patient?

When the image intensifier is moved closer to the patient, the radiation field at the tabletop increases. This is due to the inverse square law, which states that the intensity of radiation is inversely proportional to the square of the distance from the source of radiation.

As the distance between the x-ray tube and the patient decreases by bringing the image intensifier closer, the amount of radiation that reaches the tabletop effectively increases because the x-rays are concentrated in a smaller area. The closer positioning of the image intensifier reduces the distance over which the radiation spreads, allowing a higher radiation dose to be delivered to the tabletop per unit area, resulting in an increased radiation field.

This principle is crucial for understanding how adjustments in equipment positioning can impact patient and operator exposure to radiation, emphasizing the importance of technique and equipment management in fluoroscopy.