Head Position: Centered in front of the cassette;
canthomeatal line parallel to the floor. For cephalometric applications, the
canthomeatal line is 10° above the horizontal, and the Frankfort plane is
perpendicular to the film.
Projection of Central Ray: Passes posterior to
anterior, perpendicular to the film.
Important Features:
Used to examine the skull for disease, trauma, and sinuses.
Best for viewing the coronoid process; a PA view with a 10° tilt is
called the Caldwell projection.
2. Lateral Skull or Cephalometric View
Head Position: Left side of the face near the cassette;
midsagittal plane parallel to the film.
Projection of Central Ray: Directed towards the
external auditory meatus, perpendicular to the film and midsagittal plane.
Important Features:
Assesses facial growth.
Reveals soft tissue profile.
Surveys skull and facial bones for disease and trauma.
3. Water's Projection
Head Position: Sagittal plane perpendicular to the
film; chin raised so the canthomeatal line is 37° above horizontal.
Projection of Central Ray: Passes through the maxillary
sinus.
Important Features:
Also known as Occipito-mental projection (variation of PA view).
Best for demonstrating zygoma fractures, paranasal sinuses, and
nasal cavity.
Shows the position of the coronoid process between the maxilla and
zygomatic arch.
4. Submentovertex (SMV) View
Head Position: Head and neck extended backward; vertex
of the skull at the center of the cassette.
Projection of Central Ray: Directed towards the vertex
of the skull.
Important Features:
Also called BASE, FULL AXIAL, or JUG HANDLE VIEW.
Best for viewing the base of the skull and zygomatic arch fractures.
Contraindicated in patients with cervical spondylitis.
For viewing zygomatic arches, exposure time is reduced to one-third
of that used for the skull.
5. Reverse Towne's View
Head Position: Canthomeatal line oriented 25-30°
downward.
Projection of Central Ray: Directed towards the
occipital bone.
Important Features:
Frankfort plane vertically oriented and parallel to the film.
Best for viewing condylar neck fractures.
Condyles are better visualized if the patient opens their mouth
widely.
6. Lateral Oblique Mandibular Body Projection
Head Position: Tilted towards the side being examined;
mandible protruded.
Projection of Central Ray: Directed towards the first
molar region.
Important Features:
Demonstrates the premolar and molar region.
Best for viewing the inferior border of the mandible.
7. Lateral Oblique Mandibular Ramus Projection
Head Position: Tilted towards the side being examined;
mandible protruded.
Projection of Central Ray: Directed posteriorly towards
the center of the ramus.
Important Features:
Often used for examining third molar regions of the maxilla and
mandible.
Provides a view of the ramus from the angle to the condyle.
Common Problems in Film Processing
1. Light Radiographs
Causes:
Under Development:
Temperature too low
Time too short
Depleted developer solution
Under Exposure:
Insufficient milliamperage
Insufficient kVp
Insufficient exposure time
Film-source distance too great
Film packet reversed in the mouth
2. Dark Radiographs
Causes:
Over Development:
Temperature too high
Time too long
Accidental exposure to light
Improper safe lighting
Developer concentration too high
Over Exposure:
Excessive milliamperage
Excessive kVp
Excessive exposure time
Film-source distance too short
3. Insufficient Contrast
Causes:
Improper processing conditions (under or over development)
Depleted developer solution
Contaminated solutions
4. Film Fog
Causes:
Excessive kVp
Improper safe lighting
Light leaks in the darkroom
Contaminated developer solution
5. Dark Spots or Tines
Causes:
Contaminated solutions
Film contaminated with developer before processing
Film in contact with tank or another film during fixation
6. Light Spots
Causes:
Insufficient washing
Film contaminated with fixer before processing
Film in contact with tank or another film during development
7. Yellow or Brown Stains
Causes:
Insufficient washing after fixation
Depleted fixer solution
Contaminated solutions
8. Blurring
Causes:
Movement of the patient during exposure
Movement of the X-ray tube head
Double exposure
Misalignment of the X-ray tube head (cone cut)
9. Partial Images
Causes:
Top of film not immersed in developing solution
Film in contact with tank or another film during processing
10. Emulsion Peel
Causes:
Excessive bending of the film
Improper handling of the film
11. Static Discharge
Causes:
Static discharge to film before processing (results in dark lines
with a tree-like image)
12. Fingerprint Contamination
Causes:
Fingerprint contamination during handling of the film
13. Excessive Roller Pressure
Causes:
Excessive roller pressure during processing can lead to artifacts on
the film.