Test Flashcards
A tungsten target can produce a continuous spectrum of x-ray photons when the X-ray tube is active. When considering the spectrum, define both x-ray beam intesnity (quantity) and the x-ray beam quality
Intensity= number of x-ray photons in the beam/ amount of energy passing through a unit area per unit of time
Quality= range of photon energies carried by x-ray beam. ‘Penetrating power’
Explain how any of the following would/nt affect intesnity and quality of diagnostic x ray beam
1) size of tube current
2) distance of the detector from the target
3) exposure time
4) target material
1) tube current has affect on beam INTENSITY but no effect on QUALITY
2) The distance from anode target effects beam INTENSITY owing to INVERSE SQUARE LAW, no effect on quality as it doesn’t change x-ray output spectrum.
3) length of exposure affects INTENSITY as this is related to number of x-ray photons produced in a period. It has no effect on quality as it doesn’t influence max and effective photon energies produced
4)target material affects intensity by reducing it as production of breaking radiation os reduced
Quality is affected depending upon the content
Q3) Derived quantities are produced from a combination of SI base units and always
contain one of the following three base units:
A) mol, K, s
(B) m, A, s
(C) mol, kg, s
(D) m, kg, s
(D) m, kg, s
How many SI units
7
SI unit for temp
Kelvin
What is equal to 1mSv
10-3 Sv
What multiplies is used to express a millionth
Micro
What is equal to A= B/C, where B is at the start
B= C x A
ATOMIC STRUCTURE
Q12) Which of the following statements about a proton is incorrect?
(A) It has a positive charge.
(B) It resides within the nucleus.
(C) It is always equal in number to the neutrons present.
(D) It is 1820 times the mass of an elect
C- it always equal in number to the neutrons present
If an atom has 8 protons and 8 neutrons, its atomic number (Z) and atomic mass (A)
will be what?
Z- 8
A= 16
What is the name of th band o electron orbitals that can jump up I’m to from the valence band via excitation
Conduction band
What is a form of electromagnetic ionising radiation
Gamma decay
What type of ionisation radiation are x-rays
Electromagnetic
What is the rotating anode disc made of
Tungsten
.
Q19) Which of the following is not a required characteristic of the filament in an X-Ray
machine?
(A) Low thermionic work function.
(B) Low vapour pressure.
(C) A strong metal.
(D) A melting point less than 1000 degrees Celsius.
D
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Q20) A continuous X-Ray spectrum is produced by which of the following interactions?
(A) An electron interacting with the inner shell electrons of an atom in the target
material.
(B) An X-Ray photon being absorbed by an electron in an atom.
(C) An electron interacting with the nucleus of an atom in a target material.
(D) An X-Ray photon being scattered by an electron in an at atom
C
Define attenuation
Reduction in the energy per unit area iof the x-ray beam
Which of the following doesn’t lead to attenuation of an X-ray
Photoelectric absorption
Inelastic scatter
Filtration
Collimation
Collimation
What is the half value sickness
The thickness of a substance that will transmit 50% of the x-ray photons to which it is exposed
What does mAs indicate
Tube charge
What does kV represent
Thousands of volts
Q25) What does ‘0.25mm lead equivalent’ mean?
(A) A material has the same mass as 0.25mm of lead.
(B) A material is made of 0.25mm of lead.
(C) A material attenuates the x-ray beam as much as 0.25mm of lead.
(D) A material has the same density as 0.25mm lead
C
24) In a Compton interaction, which of the following is true?
(A) The scattered photon can be diverted in any direction.
(B) The photon is totally absorbed.
(C) A characteristic x-ray and an electron are emitted.
(D) An alpha particle is spontaneously emitted by the photon.
A
when can a person carry out exposure
in administration , the practitioner and employer are licensed to undertake the intended exposure
it has been justified by the practitioner as showing a sufficient net benefit
it has been authorised by the practitioner or the operator
reseacrh programme which has been approved
enquired pregnancy for childbearing potential
urgency of exposure
what are the general duties of an employer
regularloy test equipment and its performance
what is the operator and practioner responsible for
responsible for carrying out the radiation exposure.
Practitioners and Operators are responsible for justifying and authorising individual medical exposures based upon assessment information supplied by the Referrer
what is the refferer resposnible for
a justifyable reasoning for refferel
what is a milli
10 -3
what is a micro
10 -6
list types of ionising radiation
alpha particles, beta particles, positrons, gamma rays, and X-rays
when are x-ray photons produced
when fast moving electrons (acceleratedby cathode) are suddenly stopped by the impact with the metal target (anode)
ke of electrons is converted to x-ray photons and into heat
in a mass attenuation coefficents pb graph, what is on the x and y axis
bottom x= photon energy
y= mass attenuation coefficency
compton scatter dominates over a wide range of energies with all materials
what is kVp
The kilovoltage peak (kVp) is the difference in potential applied to the X-ray tube
