Within what percentage must the Source-to-Image Distance (SID) be accurate?

The Source-to-Image Distance (SID) must be accurate within 2% to ensure optimal image quality and accurate radiographic measurements. Accurate SID is crucial because it affects the magnification, geometric sharpness, and dose received by the patient. If the SID deviates significantly from the prescribed value, it can lead to errors in the interpretation of the image, affecting the diagnosis and potentially compromising patient safety.

Maintaining this level of accuracy helps to ensure that the radiation dose is appropriate for the distance used, which ultimately contributes to consistent and reliable imaging results. A 2% tolerance level is considered the standard in radiologic practice, balancing the technical capabilities of the equipment with the need for precise imaging outcomes. This level of accuracy is a key aspect of quality assurance protocols in radiology departments.