Technique charts

The technique chart is a priceless resource that provide a:

consistent method to choose the exposure factors

The chart is broken down by the:

1. thickness

2. body part to be radiographed

3. kVp, time, mA

Other factors that are specific to the chart:

-Speed of screens

-Age of screens

-Source-image distance

-Amount of beam filtration

-Temperature and time of film processing

-Type of grids

The only factors that should change are the:

type of screens or film used

Even if you only have one type of screen and

film, you still need multiple charts to

compensate for specific:

1. Species

2. Anatomy specific

3. Grid or non grid (tabletop or Bucky)

extremity, skull, avian, exotics

table top, no grid

abdomen, thorax, pelvis, spine

grid

Need ___ inch film with the speed of film you will normally use

14x17

Santes’ Rule:

(2 x thickness + 40 + grid factor) = kVp

Milliamperage:

highest setting possible (100 or 300)

Grid Ratio: 5:1;

Added kVp to sum:

6-8 kVp

Grid Ratio: 8:1;

Added kVp to sum:

8-10 kVp

Grid Ratio: 12:1;

Added kVp to sum:

10-15 kVp

Grid Ratio: 16:1;

Added kVp to sum:

15-20 kVp

Fast screen types

2.5 to 10 mAs

Medium screen types

5 to 12.5 mAs

Slow screen types

30 to 40 mAs

5 mAs = 300 mA X ____ sec

1/60

7.5 mAs = 300 mA X ____ sec

1/40

10 mAs = 300 mA X ____ sec

1/30

12.5 mAs = 300 mA X ____ sec

1/24

Add ___ kVp for each increase in thickness up to 80 kVp

2

Add ___ kVp for each increase in thickness between 80-100 kVp

3

Add ___ kVp for each increase in thickness over 100 kVp

4

Increase mAs by 50% when an animal may have these 3 things:

1. Pleural fluid/massive cardiomegaly

2. Ascites

3. Obesity or heavy muscling

4. Plaster casts

Increase mAs by 50% when doing these 2 things with an animal:

1. Special procedures using radiographic contrast

2. Foam trough is used for positioning

Decrease mAs by 50% when a dog or cat is a:

Neonatal