An extra-oral imaging apparatus is intended to obtain a cephalometric image of a portion of a head of a patient. Exemplary apparatus embodiments of cephalometric functionality of such extra-oral imaging apparatus can include a cephalometric support mounted to a base of the imaging system that is configured to position a cephalometric sensor about a cephalometric imaging area so that x-rays impinge the cephalometric sensor after radiating the cephalometric imaging area. A cephalometric collimator can be mounted to a patient positioning unit to provide secondary collimation of the x-ray beam for the cephalometric sensor. Exemplary apparatus and/or method embodiments of the application relates to providing a measurable indication of alignment between a cephalometric collimator and cephalometric sensor or the extra-oral imaging apparatus, which can provide a repeatable and/or accurate alignment between a cephalometric collimator and cephalometric sensor.