Physics test 2 Flashcards
T/F Overexposing to eliminate noise is a violation of ALARA.
True
The exposure number comes from which of the following:
a. coherent radiation
b. remnant beam
b. light beam
c. scatter
b. remnant beam
When you think of scatter, which of the following do you think of?
a. coherent b. photoelectric c. compton d. remnant beam
c. compton
What is the phosphor layer in the reader made from?
barium fluorhalide
What is the order of the layers of the reader, top to bottom:
a. support layer, conductive layer, reflective layer, phosphor layer, protected layer b. protected layer, phosphor layer, conductive layer, reflective layer, support layer c. protected layer, phosphor layer, reflective layer, conductive layer, support layer d. phosphor layer, protected layer, reflective layer, conductive layer, support layer
c. protected layer, phosphor layer, reflective layer, conductive layer, support layer
Which layer sends light in a forward direction?
reflective layer
What does the material in the phosphor layer do?
traps the electrons
What does a photo multiplier do?
converts light to an electronic signal
How does a reader create an image after the cassette is inserted?
PSP is exposed, laser scans, light is given off, photo multiplier, digitizer
What does a digitizer do?
it converts an electronic signal to a number (an analog to digital converter)
T/F The numbers in the matrix are associated with black and white.
False (various shades of grey)
Brightness is what we refer to on an analog image as:
Density
What is the term for a formula in a computer?
Algorithm
What is the term for the graph of the exposure?
Histogram
Which comes from the patient?
a. photoelectric xrays b. coherent scatter c. compton scatter d. bremsstrahlung
Compton Scatter
When a proton hits an inner shell electron, ejecting it, this is called:
Photoelectric Effect
Compton scatter does which of the following:
a. increases resolution, making the image darker b. creates a layer of density, making the image clearer c. creates a layer of density, making the image darker d. increases resolution, making the image clearer
creates a layer of density, making the image darker
How does the laser scan the PSP in the reader?
In a raster motion
Why are photoelectric rays referred to as money?
Because of the complete attenuation
Which of the following is true of bremsstrahlung:
a. Move from L to K shell b. are slow-moving c. move from the M to k shell d. all of the above
Move from L to K shell (not enough energy in other transitions, is fast-moving, electron comes close to the nucleus, changes direction)
What is the term used for absorption of energy?
Attenuation
T/F When an electron is ejected from an inner shell resulting in a cascade effect, low energy photons are produced.
True (photoelectric effect)
Which is true of the grid:
a. it absorbs scatter b. it is a series of strips made from rare earth metals c. primary beams are absorbed d. all of the above
it absorbs scatter (strips made of lead, primary beams go through)
T/F Compton scatter is found in things with a high atomic number, such as bone, lead, and barium.
False (photoelectric)
Image receptors have intensifying screens made of rare earth phosphors (Gadolunium, Lanthanum, yettrium), why?
a. rare earth metals require less radiation b. to absorb radiation and give off light c. it creates a density that results in an image on the film d. all of the above
All of the above
. T/F Rare earth phosphor is difficult to work with.
True
T/F Thicker body parts require a grid, because they produce more scatter.
True
The slats in the grid do what?
Absorb the scatter
What are the steps for processing film in a dark room?
developer, fixer, water, dryer
Which of the following is an alkaline solution containing six chemicals including sulfide?
a. fixer b. drying solution c. developer d. brightener
Developer
. Each square on a matrix is ____ pixel (s).
1
Which would have a better resolution:
a. large format with very tiny pixels b. small format with very tiny pixels c. large format with large pixels d. small format with large pixels
large format with very tiny pixels
Which of the following is a drawback to images with increased resolution:
a. longer processing time b. longer transmission time c. takes up more storage space d. all of the above
All of the above
The numbers on the matrix correspond to what?
A shade of gray
Advantages of digital over analog include: I. better access to images II. ability to tweak III. difficult to lose image IV. increased throughput
I, II, III, and IV
. Which of the following is false with regards to C.R.?
a. Spacial resolution is better. b. Brightness replaces density c. The digitizer converts light to a number d. Soft tissues are better demonstrated
The digitizer converts light to a number (digitizer converts an electronic signal to a number, while the photo multiplier converts light to an electronic signal)
T/F In C.R., cassettes can be reused multiple times before they need to be erased.
False (they must be erased between each use to avoid double exposure)
T/F Tweaking is done post processing.
True
The benefits of tweaking include:
a. saves repeat exposure d. decreases throughput c. can fix blurriness caused by a patient moving d. can be done before processing
Saves repeat exposure
What is the term for the beam that exits the patient?
Remnant beam
Where do target interactions take place?
Anode
Incidence electrons come from:
The cathode
