How often should Light & X-ray Field Alignment be checked?

• A. Annually
• B. Semi-annually
• C. Monthly
• D. Quarterly

Answer: (B)

Light field alignment is about making sure the visible light field that you see matches exactly the X-ray field that ends up exposing the patient. If these don’t align, you can irradiate more tissue than intended or miss the area you want to image, which affects both patient safety and image accuracy. The standard practice is to check this alignment on a semi-annual basis. Alignment tends to shift slowly over time unless the unit is moved, serviced, or bumped, so checking every six months provides a reliable balance between catching drift and keeping downtime minimal. If the equipment has been serviced, moved, or you notice any indication of misalignment, you should test it sooner. The test itself uses a suitable phantom or alignment tool to verify that the light field edges and the actual radiation field align at a given distance, within the established tolerance.