What is the consequence when the source to skin distance is increased?

Increasing the source-to-skin distance (SSD) leads to a decrease in the entrance skin dose. This principle is rooted in the inverse square law, which states that as the distance from a radiation source increases, the intensity of radiation (and therefore the dose) received decreases.

In practical terms, when the distance between the radiation source and the patient's skin is increased, the radiation spreads out over a larger area and results in lower doses being delivered to the skin. By maximizing this distance, healthcare providers can effectively minimize radiation exposure to the patient, thereby enhancing safety and reducing the risk of radiation-related complications. This is particularly important in procedures involving diagnostic imaging or radiation therapy, where minimizing patient exposure is a critical component of care.

While scattered radiation may still be a consideration, the primary effect of increasing the SSD directly influences the entrance skin dose by reducing it.