During panoramic imaging, improper placement of a thyroid collar may cause which effect on the image?

During panoramic imaging, improper placement of a thyroid collar may cause which effect on the image?

• A. A radiopaque shadow across the image
• B. Improved contrast
• C. No effect on image
• D. Reduced patient dose with no artifact

Answer: (A)

In panoramic imaging, anything that sits in the path of the X-ray beam can create an artifact. If the thyroid collar is placed improperly, it can block part of the beam and show up on the radiograph as a radiopaque shadow across the image. Lead is highly radiopaque, so where the collar overlaps the beam, that area is recorded as a bright white band, obscuring underlying anatomy. This is why improper placement leads to an artifact rather than better contrast or a harmless effect. Proper technique aims to position shielding so it does not intrude into the imaging field, or to avoid shielding in panoramic exams to prevent such shadows.

In panoramic imaging, anything that sits in the path of the X-ray beam can create an artifact. If the thyroid collar is placed improperly, it can block part of the beam and show up on the radiograph as a radiopaque shadow across the image. Lead is highly radiopaque, so where the collar overlaps the beam, that area is recorded as a bright white band, obscuring underlying anatomy. This is why improper placement leads to an artifact rather than better contrast or a harmless effect. Proper technique aims to position shielding so it does not intrude into the imaging field, or to avoid shielding in panoramic exams to prevent such shadows.