radiology 2nd half

What technique uses the Rule of Isometry

Bisecting technique

What line does the central ray hit in bisecting?

The imaginary bisector

What causes foreshortening?

Too much vertical angulation

What causes elongation?

Too little vertical angulation

When is bisecting used?

Small mouths, tori, shallow palates, children

How can you tell a PA was taken with bisecting?

Distortion, steep vertical angulation, receptor close to tooth

What type of image shows both jaws in one view?

Panoramic

Is a pano intraoral or extraoral?

Extraoral

What is a ghost image?

Larger, higher, blurry opposite-side duplicate from metal

How do you identify jewelry ghost images?

Opposite side, higher, magnified, blurry

What causes a dark band over maxillary roots?

Tongue not on the palate

What makes anterior teeth look skinny?

Teeth too far forward

What makes anterior teeth look wide?

Teeth too far back

What error causes a reverse smile (frown)?

Chin tipped too high

What error causes an exaggerated smile?

Chin tipped too low

What causes a white band down the center?

Patient slumped / cervical spine

How do you know pano positioning is correct?

Normal smile curve, teeth proportional, condyles visible

What extraoral view is used for kids or limited opening?

Lateral jaw projection

What view shows mandibular premolars/molars?

Body of mandible projection

What view shows ramus and third molar region?

Ramus projection

What extraoral image is used for ortho?

Lateral cephalometric

What image shows a side profile?

Lateral ceph

What projection best shows sinuses?

Waters projection

What view shows base of skull + zygomas?

Submentovertex (SMV)

What view is best for condylar neck fractures?

Reverse Towne

What view has forehead + nose touching receptor?

Posteroanterior (PA)

What image shows TMJ open/closed?

Transcranial TMJ

What imaging slices the TMJ into layers?

TMJ tomography

A panoramic radiograph shows a large, blurry, radiopaque shape high on the left side of the image. It appears duplicated and slightly distorted.

Ghost image from jewelry

The inferior portion of the panoramic image is blocked by a large radiopaque area that curves upward like a white hill.
What is the error?

(Lead Apron Artifact) Thyroid collar was used during a panoramic image

A vertical radiopaque band appears in the center of the pano, obscuring the anterior teeth and nasal structures

Patient slumped, causing cervical spine to superimpose

A dark radiolucent band covers the apices of the maxillary teeth on the pano, making them hard to evaluate.

Tongue was not placed against the palate

The panoramic image shows a flat or inverted smile line. The hard palate is superimposed over the maxillary roots.

Chin tipped too far up - reverse smile line

The smile line is exaggerated, the mandibular incisors appear blurry and elongated, and the condyles are cut off

Chin tipped too low

The anterior teeth on the pano appear skinny and blurred, and the spine shadow is more visible.

Patient was positioned too far forward on the bite block

The anterior teeth appear wider and blurry, and the condyles may appear near the edges.

Patient positioned too far back (posterior)