Exam Prep - Peter Flashcards
What is quality
Range of photon energies carried by the beam “penetrating power”
What is intensity
Equal to the number of photons in the beam
Factors affecting the quantity & intensity
Size of the tube current
Distance between the detector & target
Exposure time
Target material
What does the size of the tube current do to quality & intensity
Intensity = increased
Quality = no change
What does the distance between the detector and target do to quality & intensity
Intensity = decreased
Quality = no change
What does the exposure time do to quality and intensity
Intensity = increased
Quality = no change
What does the target material do to quality & intensity
Intensity = increased/decreased
Quality = no change
What is the duty of a referrer
Health care professional entitled to request/refer for medical exposure (must have clear medical evidence to justify the reason for exposure)
What is the duty of the operator
Responsible for the practical aspect (performs & optimises medical exposure)
What is the duty of the practitioner
Responsible for the justification of exposure
What are the factors should be considered when justifying a radiographic exposure
Objectives
Characteristics of the individual
Total potential diagnostic
Benefits / risks
Efficiency, benefits & risks of alternative methods
Describe continuous radiation
Continuous X-ray spectra
Produced by breaking radiation
Electron is attracted towards a nucleus & deviated, giving off an IR photon
Describe characteristic radiation
Line spectra
Electron is accelerated towards a target metal, hits an electron in the atoms shell and causes it to be ejected
Electron from a higher energy level gives off a photon & drops down an energy level top fill the space in the shell
What is Compton scatter
X-ray photon interacts with an outer shell electron causing the photon to change direction
What is photoelectric absorption
X-ray photon gives up all energy to eject an electron from its shell
What is thermionic emission
Putting enough energy into the filament to liberate the electron
What does Kv represent
Tube charge
What does Mas represent
Tube current
How many base units are there
7 base units
What are derived units
Always contain on of the following base units: m, kg, s
What are vector quantities
Quantity with direction & magnitude
What are scalar quantities
Quantities with magnitude only
What does a Kilo (k) represent
1000
(Multiple)
What does a Milli (m) represent
0.001
(Submultiple)
What does a micro represent
0.000001
What is the atomic mass
Number of protons & neutrons (top number)
What is the atomic number
Number of protons in the nucleus (bottom number)
What are the electric charges for P, N & E
Proton = +1
Neutron = 0
Electron = -1
What are the sources of EIR
X-rays (electromagnetic spectrum)
What are the types of IR
X-rays
Alpha particles
Beta particles
Gamma rays
How are X-ray photons produced at the atomic level
X-ray photons a produced by accelerating electrons towards an anode target
What is half value thickness
The thickness of a substance which will transmit one 1/2 of the intensity of the radiation incident upon it
Define absorbed dose
The energy deposited per unit mass
Define equivalent dose
A measure of the radiation dose to tissue
Define effective dose
Compare the stochastic risk of non-uniform exposure to radiation
What are grids and their uses
Grids are made up of strips of lead & low-attenuation material
Reduce scatter - scattered photons hit the grid & are absorbed by lead strips
What is deterministic risk
Have a threshold dose below which the effect will not occur
What is stochastic risk
It is a chance as to wether or not the person will develop cancer
