Exposure Guide for Lateral
Cephalometric Radiographs
Distance = X-ray Source to
Film
Cassette = 8x10" with high
speed intensifying screens
Film Kodak T-M-L (or
equivalent 400 speed film).
With rare earth screens
(Kodak Lanex regular).
Substitutions or mixing
manufacturers risks good
results.
|
KV |
Ma |
Distance |
Exposure Time |
|
60 |
10 |
54 |
1.2 |
|
65 |
07 |
54 |
0.9 |
|
70 |
07 |
58 |
1.0 |
|
70 |
10 |
60 |
1.0 |
There are only two
adjustments you can make for
good exposures:
- Exposure time.
Exposure Time should not be
greater than 1.2 seconds. If
you can't
get a clear Sella at about 1
second then shorten the
distance.
- Exposure distance. If your
x-ray power is less thank 70
KVP-10ma you will need to
shorten the distance between
the two units as Indicated
above.
When in doubt, go a little
shorter.
Exposure times and distances
are relative and may require
adjustments + or -.
Generally increase
exposure time until Sella
Tursica is visible and
decrease to show soft
tissue. Adjust + & - until
you get both Sella and soft
tissue.
Exposure time increases at
the square of the distance.
Development technique, as
always, is a significant
part of ultimate film
quality. Using quality
developing chemicals and
professional standards in
the darkroom will result in
diagnostic quality
radiographs.
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