Fluoro exam Flashcards
During a fluoro exam knowledge of _____ can ensure the lowest dose whole achieving diagnostic image?
optimal exposure factors
_____ is the measure of tube potential
kVp
Increase kVp results in?
- lower pt. dose
- Decrease in ESE
- Decrease subject contrast
- Increase radiate dose at input phosphor
x-ray output is directly proportional to____?
mA
____ is the quality of the beam
while ___ is the intensity of the beam
- kVp
2. mA
Image quality will improve with ____?
well collimated areas
Will image brightness increase with enlarged FOV?
no
Increase in mA results in?
- Brighter image
- Increased pt. dose
- Increase operator dose
Increased collimation results in?
- Decrease pt .dose
- Increase image quality
- Decrease integral dose
_____ is the total of energy from the beam absorbed by the patient
Integral dose
unit= gram rad
What is the unit of integral dose
gram rad
1 gram = 100 ergs
material placed in the primary beam to absorb less penetrating x-ray photons is known as?
filtration
What is the main purpose of filtration
reduce the # and amount of low energy (long wavelength) x-rays from reaching the patient
Inharent & added filtration = ____ for fluoro operating at normal ( 80-120) kV
at least 2.5 mm Al
Inharent & added filtration = ____ for fluoro operating up to 150 kV
at least 3 mm Al
Filtration results in?
- Decrease scatter radiation
- Increased image quality
Thickness of absorbing material necessary to reduce the x-ray beam intensity to half the original value
HVL
What defines the quality of the x-ray beam
HVL
Exposure Time—should always be kept to a _____
minimum
Manual reset timer may not exceed ___ min.
5 min
Allowable exposure rates may not exceed ___ per minute
10 rads / min
Allowable exposure rates amount to ____ /____ per each mA
2.1 / 2.2
For units with ABC/AEC the operator must do a quality control check of kVp and mA _____?
once each week
What does TPD stand for? What is it?
Target to panel distance
- Applies to mobile fluoro
- ESE should range 12-18”
I.I should be as ___to pt. as possible to ____
- close to pt.
2. minimize exposure
What is SSD
Source to skin distance
For:
*mobile - should not be less than 12” (30 cm)
*Stationary fluoro units- should not be less than 15” (38 cm)
Lighting in fluoro room should be dim to ____
maximize visualization of monitor screens
Excessive room lighting during a fluoro exam could lead to ____
increase in technical factors in order to increase brightness on the screen
Poor IR quality can result in attempted compensation by increasing technical factors. This can result from:
- Age
- Misaligned I.I
- Damaged parts
Name 2 low absorption table tops
- Al ( may not be more than 1 mm @ 100 kVp)
2. Carbon fiber (reduces pt. dose)
What is the most effective type of shield
shaped contact shield
-protects 97% beam
Gonadal shielding may be at least ___ Pb equiv.
.5 Pb
Bucky slot opening must be covered with at least _____ equiv. material
.25 mm PB
What are advantage of 3 phase / high frequency generators
- Near constant tube potential
- High mA available for short exposures
- Higher effective kVp
- These advantages not as applicable in standard radiography
What is the purpose of “last frame hold”
reduce pt. dose
Why would you utilize photospot as opposed to spot film
to cut pt. dose
If playbacks are necessary, which devices are used
video recording or photospot
The law of Bergonie & Tribondeau states that ____are more susceptible to effects of radiation due to their tissues undergoing higher rates of cell division than ____.
- children
2. Adults
True or False: Pediatric fluoro exams should only be considered when radiography can’t produced the necessary information
True
What are immobilization devices used for peds fluoro
- papoose board
- Sandbags
- Compression devices
For mobile fluoro, A ______ must be in place to limit Source-to-skin distance to not less than 12
spacer (cone)
True or false : Protective aprons of at least .25 mm Pb equivalent must be worn if one is likely to receive 5 millirads/hr or more
True
When should boost mode be used:
only after locating area of interest with normal mode and “boost” is required to visualize structures
