Question 1

Which of the following is the correct reason that a cape-style lead barrier without a thyroid collar be used when exposing panoramic radiographs?

Accepted Answer

The thyroid collar can interfere with the path of the x-ray beam during panoramic radiography, potentially obscuring important diagnostic information, hence a cape-style lead barrier without a thyroid collar is used.

Question 2

Which of the following would correct an exaggerated smile appearance of a panoramic radiograph?

Accepted Answer

Repositioning the ala-tragus line at 5 degrees positive helps to correct the exaggerated smile appearance by ensuring the occlusal plane is properly aligned, reducing distortion.

Question 3

Positioning the arches too far forward in the focal trough, toward the tube head, will result in:

Accepted Answer

Positioning the arches too far forward in the focal trough will result in the anterior teeth appearing blurred and diminished in width due to the increased magnification.

Question 4

Each of the following may be used to position the patient within the focal trough EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

A chin rest, forehead rest, and bite block are all devices that can be used to position the patient's head and stabilize the jaw in the correct position for imaging within the focal trough. However, the film holder does not directly position the patient within the focal trough, but rather holds the imaging medium (such as a digital sensor or film) in place during the imaging process.

Question 5

If a resultant panoramic image shows a reversed smile (frown), the likely cause is that:

Accepted Answer

When a patient's chin is too high while taking a panoramic image, it can result in a reversed smile (frown) appearance. This is because the image projection is distorted, and the curving of the jawline appears to be inverted.

Question 6

Which of the following facial landmark planes must be positioned slightly (5˚) down toward the floor when positioning the arches within the focal trough?

Accepted Answer

The ala-tragus line, which runs from the ala of the nose to the tragus of the ear, should be positioned slightly downwards (5˚) to ensure proper alignment of the dental arches within the focal trough during panoramic radiography.

Question 7

Each of the following statements regarding fundamentals of panoramic radiography is correct EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

In panoramic radiography, the x-ray source and the film move in opposite directions around the patient's head, creating a panoramic image.

Question 8

Which of these statements regarding the focal trough is FALSE?

Accepted Answer

The focal trough, also known as the image layer or sharpness layer, is a three-dimensional curved zone in which structures are most clearly imaged in panoramic radiography. It is not two-dimensional; its three-dimensional shape accommodates the jaw's curvature.

Question 9

What is the corrective action for a panoramic image that can mimic caries of the anterior teeth?

Accepted Answer

The answer of What is the corrective action for a...

Question 10

Which of the following describes the collimator of the panoramic x-ray beam?

Accepted Answer

The collimator of the panoramic x-ray beam is a narrow slit that helps to shape and focus the X-ray beam. This narrowness helps to reduce scatter radiation and ensure more accurate imaging.

Question 11

Positioning the arches too far back in the focal trough, toward the tube head, will result in:

Accepted Answer

The answer of Positioning the arches too far back in...

Question 12

Each of the following will appear radiolucent on a panoramic radiograph EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

The orbit, maxillary tuberosity, zygoma, and lingula are all structures that will appear radiolucent on a panoramic radiograph. However, the EXCEPTION is A) the orbit, as it will appear radiopaque due to the presence of bone.

Question 13

Each of the following will appear radiopaque on a panoramic radiograph EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

The infraorbital foramen appears radiolucent on a panoramic radiograph because it is an opening in the bone through which nerves and vessels pass, not a dense structure that would appear radiopaque.

Question 14

Each of the following is a patient positioning consideration for producing a quality panoramic radiograph EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

The patient can be positioned in either standing or sitting position for a panoramic radiograph.

Question 15

Each of the following is an advantage of panoramic radiographs EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

The exception is that there is increased image distortion with panoramic radiographs compared to other types of radiographs such as intraoral radiographs.

Question 16

Which of the following describes the correct head positioning for a panoramic radiograph?

Accepted Answer

The correct head positioning for a panoramic radiograph involves having the Frankfort plane parallel to the floor and the midsaggital plane perpendicular to the floor. This ensures that the dental arches are properly aligned in the image.

Question 17

Which of the following patient positioning errors would most likely result in a wide radiopaque image of the cervical vertebrae superimposed over the anterior teeth?

Accepted Answer

When a patient does not stand or sit up straight during a panoramic radiograph, the cervical vertebrae can appear as a wide radiopaque shadow over the anterior teeth due to the spine being projected into the image.

Question 18

What is the area between the x-ray source and the image receptor that will be recorded in relative detail on the resultant radiograph called?

Accepted Answer

The area between the x-ray source and the image receptor that will be recorded in relative detail on the resultant radiograph is known as the focal trough or the "zone of sharpness". This is the area where the anatomy is in focus and appears clearly on the radiograph. The negative shadow is an area on the radiograph where no radiation has passed through the patient, creating a white area. A ghost image is an artifact that appears on the radiograph as a faint duplicate of an object due to radiation bouncing off other structures. The rotational center is the point at which the x-ray tube and image receptor rotate around during a cone beam CT scan.

Question 19

The greatest limitation of panoramic radiographs is the inability to:

Accepted Answer

Panoramic radiographs provide a broad view of the jaws, teeth, and surrounding structures, but they lack the detail necessary for high image sharpness, especially when compared to intraoral radiographs. This limitation affects the ability to see fine details such as early-stage caries, small fractures, or precise tooth root details.

Question 20

Each of the following statements regarding principles of panoramic radiography is correct EXCEPT one. Which one is the EXCEPTION?

Accepted Answer

The x-ray beam is directed toward the moving cassette, not the stationary cassette. The x-ray tube head moves around the patient's head while the cassette moves in the opposite direction, creating the panoramic image.

Quiz 30: Radiographic Techniques