Modules 1,2,&3
A simple coil of wire with a current is a ________
Solenoid
Increasing an anode's angle has the effect of ______ the effective focal spot.
Increasing an anode's angle has the effect of _INCREASING_ the effective focal spot.
As the matrix increases for a CR image; what effect does this have on the image's spatial resolution?
Increases
As matrix size increases, spatial resolution increases.
About how many shades of gray can the human eye distinguish?
32
An atom has an atomic mass of 90. If this stable atom has 40 electrons, how many neutrons does this atom have?
50 Neutrons
In a stable atom there are the same number of protons and electrons. So, 90 (atomic mass) - 40 (protons)= 50 neutrons
An AC generator produces 60 cycles per second. What is it's frequency?
60
Frequency is the number of cycles per second.
The anode is the _____ side of the tube and the cathode is the ______ side of the tube.
The anode is the ___positive__ side of the tube and the cathode is the ____negative__ side of the tube.
Which layer of the CR plate is responsible for trapping electrons during the exposure forming the latent image?
Phosphor layer
A matrix of 225x225 will consist of how many pixels?
50,625
A device has 200 ohms as resistance and is placed in a 240 volt circuit. What is the current of this circuit?
1.2 Amperes
V=I x R
240volts/200 ohms= 1.2Amps
Suppose a transformer has 200 turns in the primary and 800 turns in the secondary. What is the MOST simplified turns ratio?
4:1
(Secondary: Primary)
800:200 (divide both by 200)= 400:100 (divide both by 100)= 4:1
Rectification is changing _______ into _______.
Rectification is changing ___AC____ into ____DC___.
Which factor sets the midpoint of the densities/ brightness that are visible on the monitor?
Window Level
What technological advancement permitted the formation of helical scanning?
Slip Rings
The percentage of characteristic x-rays in the beam produced with 65kVp set at the control panel is:
0%
Characteristic requires a kVp of at least 70kVp because characteristic interactions interact with the k-shell.
With a step down transformer, current will ______ & voltage will ______.
With a step down transformer, current will _INCREASE__ & voltage will _DECREASE_.
Which TWO components of the image intensifier tube produce visible light?
Input phosphor & Output phosphor
The number of shades of gray that can be demonstrated in a digital image is indicated by:
Bit Depth
The smallest component of the digital matrix is a ______
Pixel (picture element)
If a pixel has a bit depth of 8, this means that the pixel can produce ______ shades of gray
256
2^n= 2^8= 256
A battery powering two light bulbs in a row is an example a ______ circuit and uses ________ flow
A battery powering two light bulbs in a row is an example a __SERIES____ circuit and uses __DIRECT CURRENT___ flow
During fluoroscopy with a fixed unit, the SSD cannot be less than ____inches
15
Generally, what is the exposure latitude for digital imaging?
–50% to +400%
Which of the following pitch's has the lowest radiation dose?
pitch= 1.5
pitch=1
pitch= 0.5
1.5
Greater the pitch, the less concentrated the radiation dose.
A CT image has a WW = 800 & WL = +200. What are the upper and lower CT Numbers?
-200 up to +600
Upper Gray level value = WL + WW/2 Upper Gray level # = +200 +800/2 = +600
Lower Gray level value = WL - WW/2 Lower Gray level # = +200 – 800/2 = -200