American Registry of Radiologic Technologists (ARRT) Practice Exam

When both source-to-image distance (SID) and object-to-image distance (OID) are proportionally increased, there is no significant change in resolution. This happens because resolution in radiographic imaging is influenced by several factors, including geometric factors such as SID and OID, but it does not vary directly with equal percentage increases in both distances.

When the SID increases, the divergence of the x-ray beam is reduced, which typically improves resolution. Conversely, an increase in OID increases the amount of scatter radiation that could potentially affect image quality. However, if both distances are increased proportionately, the adverse effects of increased OID can be balanced out by the benefits of increased SID.

Consequently, as the proportional relationship maintains between SID and OID, the overall effect on resolution stabilizes, leading to no significant change in the clarity of the image. Understanding the interplay between these distances is crucial in radiography to optimize image quality without over-complicating matters.