If a radiograph is acquired using a 40 inch (102 cm) source-to-image distance (SID) and the SID is increased to 60 inches (152 cm), the receptor exposure will:

When the source-to-image distance (SID) is increased, the intensity of radiation that reaches the image receptor decreases due to the inverse square law. This law states that the intensity of radiation is inversely proportional to the square of the distance from the source. In simpler terms, when you double the distance, the intensity of radiation reaching a point one unit away is reduced to a quarter of its original value.

In this scenario, when the SID is increased from 40 inches to 60 inches, the increased distance results in a significant reduction in the amount of radiation that targets the receptor. Hence, the exposure or density of the radiograph will decrease. This is because the same amount of radiation is now distributed over a larger area due to the increased distance, leading to less exposure per unit area on the receptor.

Overall, knowing how SID affects exposure is crucial in radiography for ensuring optimal image quality and proper diagnostic information while minimizing patient exposure to radiation.