What is an acceptable source to skin distance (SSD) when operating a stationary fluoroscope?

When operating a stationary fluoroscope, the acceptable source to skin distance (SSD) is critical for minimizing patient radiation exposure. A distance of 40 cm is established as the standard because it significantly reduces the radiation dose received by the patient's skin. The farther the radiation source is from the patient, the less radiation dose reaches the skin due to the inverse square law, which states that radiation intensity decreases proportionally to the square of the distance from the source.

At 40 cm SSD, the system achieves a good balance between effective imaging quality and safety regarding radiation exposure. This standard helps ensure that patients are protected from excessive doses while still allowing clinicians to carry out necessary diagnostic and therapeutic procedures. Other distances, such as 30 cm or 20 cm, would result in increased radiation exposure, whereas 50 cm may not be practical for all procedures, even though it would further reduce exposure. Therefore, 40 cm is considered an optimal and acceptable margin for stationary fluoroscopes.