Important Info Flashcards
Mass number of 8 and Atomic number of 6. What is true?
6 protons, 2 neutrons
Binding energy in the innermost shell have _________ energy than outermost. And electrons in the K shell of a larger atom have a __________ energy than an atom with a smaller atomic number.
greater
greater
What is true about ionization?
a. photon energy has to be greater than binding energy
b. ion pair formed
c. both are true
d. both are false
c. both are true
Which one of these is particulate radiation?
a. proton
b. x-ray
c. gamma
d. UV
e. None of the above
a. proton
(is this supposed to photon?)
What is true about x-rays?
a. no charge
b. has weight
a. no charge
Which of the following is part of the cathode?
a. filament
b. focusing cup
c. copper anode
d. a and b
e. b and c
d. a and b
Where does the electron beam decelerate?
tungsten target
Which of these is true about the focal spot?
effective focal spot creates sharper image
What makes up the majority of radiation in x-ray beam?
Bremsstrahlung
What is true about Bremsstrahlung?
a. interacts with nucleus
b. heterogenous
c. interacts with electrons
d. specific amount of energy
e. a and b
f. c and d
e. a and b
What happens to most of energy from cathode beam?
becomes heat
What is true about characteristic radiation?
outer shell electron moves into inner shell
What is true about step-down transformer?
a. controls heat to cathode
b. controls cathode to anode electron
c. part of high-voltage circuit
a. controls heat to cathode
What does increasing kV affect?
a. increasing cathode electrons boiling off
b. part of high voltage circuit
c. part of low voltage circuit
no answer on file
- b. part of high voltage circuit?
What does a rectifier do?
a. convert AC to DC
b. changes voltage of AC current
a. convert AC to DC
Direct current has _____ energy than alternating current. Direct has _______ radiation exposure to patient.
higher
lower
What happens if you alter tube current?
changes quantity but no quality
What does filtration effect?
mean energy increases
max energy stays the same
8 inch to 16 inch tube: what happens?
1/4 of the intensity of the beam is produced
Which of these affects contrast?
a. kV
b. mAs
c. kV and mA
d. kV and exposure time
a. kV
- kinda confused about this
If you have less contrast you have ____ shades of gray
more
Which one of these has a chemical change to produce an image?
a. CCD
b. PSP
c. Film
d. CMOS
c. Film
What makes up the grid in a solid-state sensor?
silicon
What is the image forming component of a solid-state sensor?
silicone
Where does the cesium scintillator operate?
a. solid state sensor
b. solid state scanner
c. PSP sensor
d. PSP scanner
a. solid state sensor
What is advantage of CMOS?
a. laser scanner
b. manipulation of image
b. manipulation of image
What is the advantage fo CMOS over CCD?
faster image processing
Which of these has the least amount of radiation?
a. Film
b. PSP
c. FPD
d. CCD
d. CCD
Which tool compromises diagnostic accuracy by unevenly altering the density histogram?
a. edge sharpening
b. contrast
a. edge sharpening
Picture of greyscale chart. What does this control?
amount of greys
What is this tool?
length calibration
What is this?
Inversion
What is this?
Edge enhancement/sharpening
Which one of these has the highest spacial resolution?
a. film
b. PSP
c. CCD
d. CMOS
a. film
- i think
5 Questions about quality versus quantity
Quantity: Number of photons in the beam. Primarily related to tube current and exposure
time
oQuality: Average energy the x-ray beam.
▪ Controlled primarily by the tube voltage (kVp)
What increases quantity: kVp, mA, exposure time, mAs
What increases quality: kVp, filtration
What decreases quantity: distance, filtration
What does higher density do?
more blackness
What is density controlled by?
mAs
exposure time
What is contrast controlled by?
kvP/voltage
If you increase kvP what happens to density?
increase
If you increase kvP what happens to mAs?
decrease
If you increase kvP what happens to contrast?
decrease
What type of sensor is a APS (active pixel sensor)?
CMOS
- CCD has a separate image sensor and image processing unit while APS/CMOS has it combined
What is true about rectification?
Options about “fully-rectified, non-rectified, “x-ray tube is self-rectified”
????? no idea
What are the properties of x-rays?
Ionize matter and have no charge
When comparing CCD and CMOS, what is true about CMOS?
faster processing and image manipulation
When comparing CCD and CMOS, what is true about CCD?
less radiation
Dr. Kells significances
1st to expose dental radiograph in the US
who designed the enclosed x ray tube that has had minimal design change?
coolidge
What decreases the quantity of x-rays?
filtration
- and prolly a lot of other stuff
How much energy is converted into x-rays?
1%
What happens at the tungsten target?
x-rays produced
Which digital imaging system has physical similarities to film?
PSP
High contrast produces what kind of greyscale?
short greyscale because of low kVp
What does this show?
edge enhancement
- unevenly alters dentsity
What is this?
inversion
If Kvp and mA are constant, then you double current what happens to exposure time to maintain?
halves
Inverse square law. If you double it, what happens?
intensity of beam is 1/4 of original
What is true of ionization?
- Ionizing energy must be greater than bindign to knock out proton
- Produce positive and negative ion from a neutral atom
Which of the following is true of binding energy?
K shell binding energy is greater than L shell binding energy
Listed 3 energy values from K,L,M shell, asked what is the minimum value to see characteristic radiation occur?
69,500 – must be equal or greater than K shell
What is true about the stationary anode line focus principle?
The effective focal spot is smaller than the actual focal spot, has sharper image
What makes up the majority of x rays?
bramsstrahlung/breaking
What does the cesium scincillator operate?
- Converts x-ray into visible light
- Operates the solid state sensor
Best image modification method?
adjust gray scale
X ray tube has what components?
a. Cathode = filament + focusing cup
b. Anode = tungsten target + copper stem
Which tool compromises diagnostic accuracy by unevenly altering the density histogram?
Sharpening
Constant potential and direct current?
Decrease radiation dose
- rectifier changes AC to direct current so you get higher energy with lower radiaiton
Chemical changes in processing is what kind of x-ray film/sensor?
film
Difference between pixels and silver halide
Options like, “Pixels are specifically organized and contain x-ray photons”
- pixels are electrified with pre-exposure electrical charge
- x-ray photons -> sensor -> change charge of pixels
- film uses silver halide chemical
- smaller the pixel the sharper the image
- PSP plates that crystallin halide emusion and produce a latent image
What does the letter A stand for?
Atomic Mass = protons + neutrons
Production of High speed electrons
- High potential difference is produced between the cathode filament and target anode by applying high voltage between them
- Most of the energy from the cathode beam becomes heat
Differences between alternating/direct current
“Constant potential & constant DC results in _____” - less radiation???
What x-ray system uses a laser?
PSP
Step up vs. Step down transformer
Step down
- low voltage circuit
- regulated by mA switch
- increasing mA = increasing electrons
- controls heat to the cathode
Step up
- high voltage circuit
- regulated by kvp
- increasing kvp = increasing energy of electrons
- attches to both cathode and anode
- determines the speed of electrons and energy of x-ray photons
Most of the energy from the cathode beam becomes…
heat
Which of the 6 factors affect quality of the x-ray beam
- Tube voltage (kV)
- Tube current (mA)
- Exposure time
- Filtration
- Collimation
- Source - film distance (inverse square)
- all six factors affect quantity (filtration, collimation, and film distance decrease it)
- only filtration and tube voltage affect quality (increases it)
What is the difference between the wave and quantum theory?
Wave Theory
- propagation of radiation in form of waves (no mass)
- electromagnetic radiaiton (wave-like energy) that travels at speed of light
Quantum Theory
- interactionof radiation with matter
- particulate radiation in the form of photons (have energy, mass, and travel in straight lines at the speed of light)
What travels like a wave?
x-rays (ionizing)
gamma rays (ionizing)
uv rays (non-ionizing)
What travels like a quantum?
alpha particles
beta particles
electrons
neutrons
protons
What are the facts about CCD?
- direct digital
- cesium iodide scintillator
- pixels -> electrical signals on silicone image forming component
- electrical charge has to move to each area to be assigned a number and sent off (slow)
- least amount of radiation
- sensor is thicker/stiffer
What are the facts about CMOS?
- direct digital
- electrical charge converted automatically in each pixel and sent to computer (faster than CCD)
- image manipulation
- faster image process (doesn’t need adjunct box)
What are the facts about PSP?
- indirect digital (PSP laser scanner -> computer)
- easier processing than film
