Final answer:
Switching from a 6-inch to a 9-inch magnification mode increases the patient's radiation dose, potentially around 1.5 times, due to the need for a higher dose to maintain image quality over a larger magnification area.
Step-by-step explanation:
When changing the magnification mode from a 6-inch to a 9-inch setting, the patient's radiation dose is affected accordingly. This is due to the fact that a larger magnification requires a greater surface area to be illuminated, which in turn requires a higher dose of radiation to maintain image quality.
Typically, when magnification increases, the area being irradiated becomes smaller, leading to an increase in radiation dose concentration. The relationship between the magnification change and radiation dose is not always linear, but it can be estimated that changing from 6-inch to 9-inch mode might increase the radiation dose by a factor related to the area of the beam's cross-section change, often approaching a direct proportion. Therefore, if other factors like geometry and beam quality are held constant, the radiation dose could increase by around 1.5 times when switching to a larger magnification mode.