Technique Chart Flashcards
What does a technique chart provide?
A consistent method for choosing the correct exposure factor settings
What is a technique chart?
A document that lists predetermined exposure factor settings based on the thickness of the region on the animals body being radiographer
What does a technique chart help avoid?
Having to recalculate each time a radiograph is taken
What are three variables effecting technique chart formulation?
X ray machine
Animal species
Anatomical region
What is extremities mostly made of?
Dense bone
What is the thorax mostly made of?
Mostly less dense lung
What is the abdomen made of?
Mostly soft tissues
What is the three things in the formulation process?
Make sure everything is working
Evaluate x ray machine line voltage and set FFD
Use intensifying screen/film combination that will be used
What is the perfect subject?
50lbs dog
Good body
Clean medium to short hair
Cooperation
Where do you measure the perfect subject?
Laterally across the thickest part of the abdomen
How do you determine the kVp requirement?
Sabres rule
What is Sabres rule?
2 x tissue thicknessCM + FFD + grid factor =kVp
Why does grid factor need to be added in santos rule?
To compensate for primary x rays absorbed by the grid during exposeur
Does the table top need a grid factor?
No
Why is mA typically set higher?
To avoid motion artifact on radiograph
What are typical mA requirements for body regions using a fast intensifying screen/film combination? 4
Extremity/skull: 2.5ma s
Thorax: 5 mA s
Abdomen: 7.5 mA s
Pelvis/spine: 10 mA s
If the film comes out to dark what should you do?
Decrease mA s by 30-50% or kVp by 10-15%
What do you do if the film is to light?
Increase mA s by 30-50% or kVp by 10-15%
Out of mA and exposure time and kVp which one is adjusted more often?
KVp
How much kVp should you add or subtract for each centimeter change in measured thickness
2 kVp
What can cause changes in tissue density affecting the quality of the radio graphic image?
Pathology and obesity
What are six reasons pathological/abnormal conditions will require adjistment of exposure
Pleural fluid/cardiomegaly As cites Obesity/heavy muscle Neonatal dog or cat Plaster casts Radio graphic contrast media
What do you increase the mA s by during pathological/abnormal?
50% unless neonatal, then decrease
