American Registry of Radiologic Technologists (ARRT) Practice Exam

Foreshortening in radiographic images occurs when the object being imaged is not aligned properly with the imaging receptor, leading to a distorted representation of the object's true size and shape. This distortion often results from the angling of the X-ray tube relative to the object being scanned. When the tube is angled, the path of the X-rays can cause certain structures to appear compressed or shortened in the final image.

In contrast, improper exposure time primarily affects image density and contrast rather than the actual shape or size of the structures imaged. Incorrect film type influences the image quality but not the geometric accuracy of the object representation. Patient movement can blur the image but does not specifically lead to foreshortening; rather, it can result in motion artifacts. Thus, the angling of the tube is the primary cause of foreshortening, as it directly affects the geometric relationships needed to accurately depict the anatomy.