Related Experiment Video
Updated: Jul 17, 2026
Three-Dimensional Cephalometric Landmark Annotation Demonstration on Human Cone Beam Computed Tomography Scans
Published on: September 8, 2023
The influence of lead thyroid collars on cephalometric landmark identification
Dirk Wiechmann1, Alain Decker, Ariane Hohoff
1Senior faculty member, Department of Orthodontics, Medizinische Hochschule Hannover, Hannover, Germany.
Objective:
To investigate whether the application of thyroid collars (TCs) affects cephalometric landmark identification.
Study Design:
A randomized and observer-blinded diagnostic study with head films taken from 2 groups was undertaken, with 1 group wearing TCs during radiography (n = 100) and 1 group not wearing TCs (n = 100). The interobserver reproducibility of 15 landmarks was evaluated using 1-way analysis of variance and independent samples t test to compare the groups.
Results:
The total mean error radius of the non-TC group (1.28 +/- 1.47 mm) was smaller (P < or = .001) than that of the TC group (1.57 +/- 1.58 mm). Three landmarks located on the hyoid bone and on the second and third cervical vertebrae were identified as the main confounding factors.
Conclusions:
Personal lead shielding of the thyroid gland affects landmark identification, but the overall clinical effect is negligible. Thyroid collars should be routinely applied during cephalometric radiography if cephalometric analyses are limited to structures above the second cervical vertebra.
