Preclinical Radio - Panoramic Radiography Theory and Principles

What are the 4 parts of the Planmeca Promax cephalometric and panoramic machine?

- lateral ceph sensor

- soft tissue filter

- radiation source for pan and lateral ceph

- panoramic sensor

What are general concepts of panoramic radiography?

- produces single image of large anatomic area

- structures are flattened and spread out

What are advantages of panoramic radiography?

- broad coverage of facial bones and teeth

- convenience for the patient

- used on compromised patients

- efficient in produce image

- low radiation dose to patient

A panoramic is equivalent to ___ bitewings

A) 1

B) 2

C) 3

D) 4

E) 5

F) 6

D) 4

What are disadvantages of panoramic radiography?

- doesn't show fine detail

- proximal surfaces of premolars overlap

- uneven magnification

- geometric distortion

- operator sensitive

- anatomy can hide area of interest

- area of interest may be outside the focal trough

What are common clinical applications for panoramic radiography?

- overall evaluation of the dentition

- dentomaxillofacial trauma

- evaluation of impacted teeth

- extensive disease

- examine intraosseous pathology

- tooth development

- edentulous patient evaluation

- implant site assessment

- gross assessment of TMJ

What are image receptors for panoramic radiography?

- CCD direct exposure

- indirect exposure

What part of the cassette interacts with radiation?

phosphors

3 multiple choice options

Why doesn't the pan provide fine details?

radiation comes through the film back to the panel and comes back out again --> spreads the image out/bounces around

How is the panoramic image created?

sequential image formation

What is the size of the focal trough affected by?

- arch path

- velocity of film and tubehead

- collimator width

True/False: the position of the object in the trough determines the size and shape of the resultant image

True

For a panoramic image, the most posterior part of structure ends up more ___

A) superior

B) inferior

A) superior

For a panoramic image, the most anterior part of structure ends up more ___

A) superior

B) inferior

B) inferior

How are real images formed?

objects that lie between the center of rotation and the receptor

How are double real images formed?

objects that lie posterior to the center of rotation and are intercepted twice by the x-ray beam

1 multiple choice option

What are structures that are double real images?

- body of hyoid bone

- epiglottis

- palatal torus

- hard and soft palate

- cervical spine

How are ghost images formed?

objects located between the x-ray source and the center of rotation

1 multiple choice option

What structures are ghost images?

- earrings

- cervical spine

- hard palate

- hearing aids

Ghost images are on the ___ side of the real counterpart

A) same

B) opposite

B) opposite

Ghost images appear ___ than the real counterpart

A) lower

B) higher

B) higher

True/False: the ghost image is more blurred than the real counterpart

True

The ___ component of a ghost image is more blurred than the ___

A) horizontal, vertical

B) vertical, horizontal

B) vertical, horizontal

True/False: ghost images appear in the same orientation as the real counterpart

True