THESE ARE RECOMMENDED TECHNIQUES: FINAL RESULTS WILL DEPEND ON MANY
FACTORS, PLEASE NOTE EXAMPLES THAT FOLLOW:If films
are too dark (overexposed) decrease
time, Halving mAs values will reduce the film blackening/density
by half, or reduce kV by 10 and keep time the same. If films are
too light (under exposed) increase time, Doubling mAs
value will double the film blackening/density, or increase kV by 10 and
keep time the same.
ADJUSTING FOR kVp THICKNESS
-
40-79kVp- add/subtract 2 kV for each 1 cm
increase/decrease in thickness.
-
80-100kVp- add/subtract 3 kV for each 1 cm
increase/decrease in thickness.
-
Increasing kVp by 10 will increase penetration/film
density by 2 (doubling) at 40-79kVp.
-
Reducing kVp by 10 will decrease penetration/film
density by 1/2 at 40-79kVp.
-
Increasing kV by 13 will increase penetration/film
density by 2 (doubling) at 80-100kV
-
Reducing kV by 13 will decrease penetration/film
density by 1/2 at 80-100kVp.
USING OPTIMAL kVp SETTINGS ENSURES HIGH CONTRAST FILMS
-
2-4 cm 50 kVp
-
5-8 cm 60 kVp
-
9-11 cm 70 kVp
-
12-15 cm 80 kVp
-
16-20 cm 90 kVp
-
21 + cm 100 kVp
FOR GRID USE:
Double mAs when using grid for same film density as
non-grid use. When doubling mAs or increasing kV by 10 does not produce
a doubling in film density, x-ray unit re-calibration may be required or
possibly a weak input line power source condition exists.
TROUBLESHOOTING
-
If your films are too gray, A) your kVp is too high.
B) Fixer is old. C) Screens are aged.
-
If your films keep getting lighter & lighter (losing
contrast) your problem is the processing chemicals, CHANGE
CHEMICALS.
-
If your films are coming out tacky (sticky): a.
weak fixer b. adjust dryer heat
-
If your processor is running hot (over 95
degrees) your films will be dark!
-
Your films will be a little dark (20%) just
after changing your chemical, until chemical is seasoned by running
10 films or new chemical sits for two days.
USE THE RIGHT CASSETTES
-
If you are using a DETAIL CASSETTE and should
be using a REGULAR CASSETTE your films will be light.
-
If you are using a REGULAR CASSETTE and
should be using a DETAIL CASSETTE your films will be to dark.
-
When going from Regular Cassettes to Detail
Cassettes multiply your technique by 2.
-
When going from Detail Cassettes to Regular
Cassettes divide your technique by 2.
ADDITIONAL NOTES
-
For every 5 cm of thickness increase, double your
mAs or time.
-
When you increase your kVp by 15%, cut your mA by
1/2 or time for same film density.
- When you decrease your kV by 15% double your mAs or time for
same film density.
| 1-800-346-9729 |
www.vetxray.com |
Sales@vetxray.com |
Diagnostic Imaging Systems,
Inc.
|
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