As source-to-skin distance (SSD) decreases, what happens to entrance skin exposure (ESE)?

As source-to-skin distance (SSD) decreases, the entrance skin exposure (ESE) increases. This principle is rooted in the inverse square law, which states that the intensity of radiation is inversely proportional to the square of the distance from the source.

When the distance between the radiation source and the skin decreases, the same amount of radiation is concentrated over a smaller area, resulting in a higher exposure to the skin. Therefore, as the SSD gets smaller, the radiation dose to the skin increases, leading to a heightened entrance skin exposure. This understanding is crucial in radiation safety and patient care, as it emphasizes the importance of maintaining appropriate distances during radiological procedures to minimize the risk of excessive radiation exposure.