What is the purpose of geometric accuracy QC in DR imaging?

• A. Ensures Accurate Distance and Alignment Between X-Ray Tube, Patient, and Detector
• B. Ensures Uniform Image Brightness
• C. Ensures Exposure Index Is Correct
• D. Ensures Detector Temperature Stability

Answer: (A)

Geometric accuracy QC focuses on preserving the true spatial relationships in the radiograph by ensuring the X-ray tube, patient, and detector are properly positioned relative to each other. When distances are correct and the beam is aligned with the detector, the image represents anatomy at the correct size and shape, with minimal distortion or magnification. This is crucial because measurements, comparisons with prior studies, and accurate localization depend on true geometry. In DR, this means checking that the source-to-image distance, object-to-image distance, and detector orientation are within tolerance and that the detector is centered and parallel to the beam. Other aspects like uniform brightness, exposure index, and detector temperature stability affect brightness, dose accuracy, and detector performance, not the geometric fidelity of the image, which is why they don’t fulfill the same purpose.