Exam 1 Flashcards
The fetus is most sensitive to radiation in what trimester?
1st
Which unit of measure is usually used for reporting occupational exposure to radiation?
REM
The focal spot size is usually set in conjunction with what?
High voltage circuit
Which primary factor is responsible for the “quality” of an X-Ray beam?
mA
The mA setting determines…
The current going through the filament
What would have the least fluctuation in the kV level?
High frequency
What propels the electrons in an X-Ray tube?
KV and Cathede
A tube warm-up procedure should be performed by using how many exposures?
2
Define: Thermionic emission
Cloud of electrons at the filament
The purpose of ____________ is to absorb unneeded X-rays
Collimator shutters
Which 3 radio graphic projections routinely uses compensating filters?
AP thoracic, Lateral thoracic, full spine
What darkens a film?
Increased kVp, increased mA, increased time of exposure, increased beam size
What lightens a film?
Increased tube distance, increased compensating filtration, decreased beam size
Lateral film is too dark and the cervical spin is larger than x-rays you took 3 months ago. Which mistakes will you accuse the operator of?
Taking the film at 40 inches instead of the 72 inches you used
What machine do you want to have
Dual focus tube with a tungsten target surrounded by copper with the same anode angle of 14 degrees and tungsten filaments
The initials FFD, TFD, and SID refer to what?
Distance between the source of the X-Ray and the film
What is the most commonly used dosimeter?
Film badge
Imagine that you are a wee little photon that has sailed through space at a high rate of speed which has carried you into and out of a patient. Which would be the next thing you encountered?
Grid
The number of electrons is controlled by…
Low voltage circuit
Which effect would a smaller anode angle have compared to a large angle?
Would create a clearer image
What contributes most radiation to a human’s annual exposure?
Radon gas
T or F: Having the anode toward the cervicals would be the most helpful in producing a good quality A-P full spine X-Ray
TRUE
In checking your collimating, what percentage is the limit of inaccuracy?
2%
Which part limits the size of the useful X-Ray beam?
Collimator
IU designation for the rad?
Gray
“Useful beam” exits which part of the tube?
Window
Filament is surrounded by…
The focusing cup
What is used to tell us that the X-Ray beam is centered to the part being radiographer?
Light and mirror
At a set FFD and film size the LESS COLLIMATION used the _______ the film will be
DARKER
You’ve taken an A-P thoracic radiograph and notice that the upper part of he spine is OVEREXPOSED. What would you do?
Use a filter for the upper part of the film
Federal regulation require how much filtration for an X-Ray machine that operates at 70 kV-100 kV?
2.5 mm
What is used for the construction of most compensating filters?
Aluminum
What allows one to move the tube stand?
Tube track
10 day rule concerns:
Patient during a 10 day period from the onset of menses
P-A would be better than an A-P because…
It will decreased breast and gonad exposure by 95%
If you had a film that was too dark what would solve your problem?
Decrease mAs
What governs the speed of electrons?
kV
Main function is the removal of soft rays?
Tube filters
Oil is normally found where in the tube complex?
Between tube and tube housing
What is the main purpose of oil in the tube complex?
To cool the tube
What is the primary controlling factor for contrast?
kV
Last thing you should do before pressing the exposure button?
Activate the rotor
Which type of anodes should you use?
Rotating
Before moving the tube stand on the track what must be accomplished?
Lock must be released
The larger or small focal spot is usually set simultaneously with the….
Milliamperes
Is you wanted to increase the number of photons reaching your film you should…
Increase the mA
Comparing 2 films with the kV and mAs constant, one taken at 40 inches FFD and the other at 72 inches FFD, what would occur?
Increased density of 40 inch film and decreased image size on 72 inch film
Which is responsible for changing AC current to DC current?
Rectifier
What stops the electrons?
Anode
Low voltage circuit would produce…
Thermionic emission (“boiling off” of electrons)
The _____ of the anode is responsible for the anode heel effect
BEVEL
Collimator allows one to control the size of the….
Useful beam
Spit screens will increase or decrease patient exposure to radiation?
Increase
Where is the added filtration located?
On the port of the tube housing
Which two areas are the MOST susceptible to develop a malignancy from Ionizing Radiation?
Bone Marrow and Breasts
