Any body part exceeding this measurement requires the use of a grid to reduce fog-producing scatter radiation
When taking a test radiograph, the following requirements should be met
medium-speed film, 50lb dog in a lateral position
When developing a variable kVp technique chart, kilovoltage should be increased or decreased by increments of _____ for each centimeter measurement
What condition may require decreasing the mAs to account for increased radiographic density?
If a radiograph is too light after taking a view of the lateral abdomen, what change may be recommended?
Increase mAs 30% to 50%
Compared with the abdomen, how much mAs does a quality view of the pelvis require?
30% to 50% more
How does a grid with a ratio of 12:1 affect the generation of your variable kVp chart?
Need to add 10 to 15 to the sum of Santes' rule
Your clinic has a 100 mA/100 kVp capacity machine with an 8:1 grid. You measure a ventrodorsal abdomen on a dog to be 22 inches. Which settings will you set first?
92 kVp, 100 mA, 1/12 sec, 8.3 mA
Using Santes' rule, calculate kVp with the following information: tissue thickness = 11cm, grid factor = 12, SID = 40 inches.
When radiographing a dorsopalmar view of an animal's limb, the primary x-ray beam enters the _____ of
dorsal aspect; palmar aspect
The positional term used to describe the part of the pelvic limb found toward the tail and proximal to the tarsus is
If a body part to be radiographed has a significant difference in density between its thickest and thinnest parts, do the following
take two separate exposures with different measurements
True or False:
Two views at 180-degree angles from each other are always required for each anatomic part
The anatomic area of interest should be as close to the film as possible in order to do the following
What is the minimum desired thickness of lead sheets used to block films?
What can be used in place of a lead sheet to block part of a film?
When radiographing a dog's abdomen, where should the primary x-ray be focused?
Caudal border of thirteenth rib
If an animal's thorax is radiographed while in right lateral recumbency, what marker should be used?
Where should the marker be placed for a limb radiographed in lateral recumbency?
Cranial to the limb
State the purpose of a technique chart
Provide a consistent method of choosing the proper exposure factor to create a diagnostic radiograph
List the factors that influence a technique chart
• Speed of screens
• Age of screens
• Speed of film
• Source - Image Distance (SID)
• Amount of beam filtration
• Temperature and time of film processing
• Type of grid
List the recommended screen variable kilovoltage peak (kVp) technique charts on the basis of anatomy for a small - animal practice
• Extremity and Skull
• Pelvis and Spine
• Avian and Exotics
Name the equipment necessary for variable kVp technique chart formulation
• Medium size dog
• 14 x 17 inch cassette
• Medium - Speed x-ray film
Describe how the exposure factors - kVp, milliamperage and exposure times - are calculated
• kVp: Santes' Rule:
(2 x tissue thickness cm) + 40 inches + grid factor
• Milliamperage: highest setting possible
• Exposure Factor: selected based on mAs needed for screen type
List the base milliamperage seconds (mAs) factors for the 3 speeds of screens
• Fast: 2.5 - 10
• Medium: 5 - 12.5
• Slow: 30 - 40
Describe the modifications necessary for the exposure technique when using a grid
• Double exposure time
• Modify kVp according to the grid ratio being used
Calculation for determining an approximate amount of kilovoltage (kVp) necessary for a given anatomic area on the basis of measurement and the grid being used: (2 x tissue thickness cm) + source-image distance + gird factor = kVp
A chart based on tissue thickness and anatomic part that can be consulted for predetermined machine settings