A 'Z' is the number of protons in the nucleus

A Electrons are arranged in shells around the nucleus at specific energy levels, C K shell binding energy increases with increasing atomic number

A proton has a mass approximately 1850 times that of an electron, An electron is not a nucleon, Positrons have the same mass a electron, There can be up to 8 electrons orbiting the nucleus in the L shell

A Are characterized by mass and atomic number, B Have the same chemical properties between isotopes of a particular element

A Frequency and wavelength of electromagnetic radiation are directly proportional to each other, B In a vacuum, velocity of radio waves is equal to that of infrared light

Travels in straight lines if unattenuated, Has wave and particle like properties, Compromises sinusoidally varying electric and magnetic fields perpendicular to each other and to the direction of travel.

They are recoil electrons produced during Compton scattering events, Their range depends only upon the density of the material through which they are travelling, They cause tissue heating

Alpha particles are helium nuclei, Some radionuclides emit electrons and characteristic x-rays, Most nuclides left in a metastable state after beta decay, emit gamma rays to reach ground state, Positron emission reduces the number of protons in an atom by 1

If stored long enough, the radioactivity of a radionuclide will drop to zero, Beta emission is at a continuous range of energies, Decay constant is the probability of nuclear decay per unit time

Physical half life is the time taken for the activity to decay to half the original value , Gamma emitting radionuclides with shorter half life are safer to use and store than those with longer half life, In 10 half lives the activity is reduced by factor of approximately 1000

Beta minus emission, Characteristics x-ray, Alpha particles, Positron emission

A Beam intensity is the total energy per unit time, C X-rays have lower linear energy transfer than alpha particles, E At equivalent energy, an x-ray cannot be distinguished from a gamma ray

Usually a voltage of 10V and a current of 10A pass through the filament, The accelerating voltage of the tube is typically in the range 60-120kV, When an accelerating electron interacts closely with a target nucleus it is deflected and slowed, losing energy that is emitted as an x-ray photon

A Occurs when moving electrons interact with target nuclei, C Is more efficient with a rotating compared to a stationary anode, D Is increased if the target atomic number is increased

Occurs when moving electrons interact with target nuclei, Is more efficient with a rotating compare to a stationary anode, Is increased if the target atomic number is increased

Increasing kV, Increasing mA, A constant potential compared to a single phase waveform

The focusing cup is negatively charged, The anode stem is a poor heat conductor, The addition of rhenium to the tungsten target increases toughness and lifespan target

Is the angle that the target face makes with the x-ray beam, Increases the tube rating if the angle is reduced , Determines the size of field covered by the x-ray beam at a given focus-film distance

Has a maximum energy determined by peak tube potential (kVp), Consists of Bremsstrahlung and characteristic radiation if the kVp exceeds the K edge energy of the anode

Electrons evaporate off through thermionic emission, It should have a low vapour pressure, It has a negative potential

Is greater if the target angle is steeper

Patient entrance surface dose, Scattered compared to primary radiation at the film, Film blackening

Increased tube filtration increases the half value layer, Total attenuation is the product of Comptoms, photoelectric and elastic attenuation effects, Half value thickness is inversely proportional to the linear attenuation coefficient, It is altered with differing atomic number materials

Is a measure of the penetrating power of an x-ray beam, Is reduced as the photon energy of the radiation decreases, Will produce exponential attenuation if a narrow x-ray beam passess through successive half value thickness of a particular material

Is measured in cm2/g, Is equal to the linear attenuation coefficient divided by the density, Is proportional to the linear attenuation coefficient

It is the fractional reduction in intensity per unit thickness, It can be used to calculate the half value thickness, The greater the different in linear attenuation coefficients between two tissues, the greater the contrast between them.

More is measured on the tube side of the patient in diagnostic radiology, There is no ionization with elastic scattering

There is an interaction with a free electron, The larger the angle of scatter, the greater the reduction in energy of the incident photon, The amount of scatter is proportional to electron density

The incident photon completely disappears, Its contribution to the mass attenuation coefficient increases approximately as the cube of the atomic number

Results in the production of characterisctic radiation, Is most important at the lower end of the diagnostic range of energies, Results in ionization of the atom

For a given element, the K-absorption edge is greater than the L-absorption edge, The K-absorption edge is important when choosing an x-ray filter, a contrast medium or an imaging phosphor

Is more effective for filtering high energy x-rays using a copper rather than an aluminium filter

Causes beam hardening

Alters the quality of the x-ray beam, May consist of a compound filter, Is generally made of aluminium in dianostic tubes

Rotating compared to stationary anodes, Larger focal spot size

Can be read directly through an electronic read-out from photoconductive silicon diodes, Is useful for personal and patient dosimetry with the use of the thermoluminescent dosimeters, May be carried out using thimble ionization chambers within the field of interest, For staff may utilize the photographic effect of silver bromide in a film badge

They are used to measure absorbed dose in diagnostic radiography, Ionization of the air in the chamber forms a measurable current by the attraction of the ions to the positive wall of the chamber and negative electrode, Parallel plate ionization chambers mounted on the collimator of an x-ray tube measure patient dose area product

Used double emulsion film, Are calibrated with caesium source, Have an open window for detection of beta particles, Use cadmium nuclei to detect neutron exposure

X-ray interactions involve outer shell electrons of the thermoluminescent phosphor, When exposed to radiation, interaction excite electrons that become trapped in the forbidden energy band, The amount of light produced depends on the energy of the photons involved in the exposure, Their response is linear with dose over a wide range

It is the process by which a material absorbs energy from an external source and reemits it as light, Intensity of light emitted from a phosphor is proportional to the intensity of the irradiating x-ray beam

Cataract, Epilation, Erythema

Leukaemia, Cancer

Is measured in Sieverts

Is measured in Joules/Kg, Is the amount of energy deposited per unit mass to a medium

Takes into consideration the different radiosensitivity of tissues, Combines organ doses to give a whole body dose, In a dental film is in the order of 0.004mSv.

The radiation weighting factor for alpha particles is 20, X-rays and beta particles have the same radiation weighting factor, For x-ray absorbed dose is equal to the equivalent dose

Colon, Breast, Bone marrow

Breast - 0.12, Thyroid - 0.05, Skin - 0.01

Absorbed dose - Joules/Kg

Diarrhea and vomiting are examples, Severity increases with increasing dose

Have a linear no threshold theory, Breast cancer is an example

The chances of producing deterministic effects is the same for x-rays and gamma rays, Deterministic effectes may be non-additive

Beta particles travel through matter at high speeds, Alpha particles travel through matter at low speeds

PA chest - 0.15mGy, Lateral lumbar spine x-ray - 12mGy, AP skull x-ray - 2mGy

CT head - 2mSv, Barium enema - 7mSv, Lumbar spine x-rays - 0.8mSv

The principal radiation sources for medical exposures is x-rays and gamma radiation , Depends on the radiosensitivity of tissues.

Cell death occurs when there is insufficient time for tissue to recover between subsequent irradiation events, Free radicals produces secondary to ionization causes chemical changes in tissues

Cataract - 5Gy, Hair loss - 2-5Gy, Transient erythema - 2Gy, Sterility - 2-6Gy, Depression of haematopoiesis - >0.5Gy

Development of cancer, Mental retardation, Decrease in IQ, Intrauterine growth retardation, Leukaemia

Foetal abnormalities - 3rd to 8th week of pregnancy, Mental retardation - 8th to 15th week of pregnancy, Growth retardation - 8th to 25th week of pregnancy

Radiation dose to the hands of staff arises from the use of radionuclides as well as from x-rays

C The average dose of radiation to the population in Cornwall from natural sources is 3 times that of the average for the rest of the UK

C Is an appropriate quantity for dosimetry in fluorascopy, E May be used to set diagnostic reference levels

B Increases in proportion to x-ray field size, C Can be calculated from knowledge of exposure factors and x-ray output data, D Can be measured from DAP if the x-ray field size and back scatter are known, E Can be measured using a TLD

A They are generally used in conjunction with filters, C They have a linear response over a wide dose range, E They can measure dose rate

A They can be reused, C They can be used to measure both shallow and deep doses, E They can be used to monitor eye doses

A Are able to identify the type of exposure, E Have a sensitivity similar to TLDs

D Aluminium oxide is used in optical stimulated luminescent dosimeters, E Optical stimulated luminescent dosimeters give readings down to 0.01mSV

A Are used for assessment of finger doses, D The dose can be read only once

C TLD crystal need to be heated to about 300'C to be read, D TLDs need to be annealed after read out, E TLD crystal can be calcium fluoride

A Sensitivity is about 0.1-0.2mSv, C Provide a permanent record of exposure

B TLDs can be used to measure dose to.a patient, C Dose to a patient can be measured with an ionization chamber, D Geiger Muller counters require a quenching agent

A Are more than 100 times sensitive than TLDs, B Measure both dose and dose rates, C Have sensitivity to the neares 1uSv, E The silicone diode detector is a common type

A TLD should not be used without a dosimeter holder, C Electronic personal dosimeters are used to detect radioactive contaimination, D The TLD holder helps to differentiate between skin doses and deeper doses, E The precision of a TLD is approximately 15% for low doses

A Have a dead time when no reading can be done, C Detect all types of radiation

A Photons of energy of 40keV react with soft tissues of the body, predominantly by the Compton reaction, B Bone has a higher effective atomic number than soft tissue for a diagnostic energy range, C For a given energy and medium in the diagnostic range the actual linear attenuation coefficient is always higher than the diagnostic range the actual linear attenuation, D The units of the mass energy absorption coefficient are centimetres (squared)/kg

A Beam quality depends on kV and voltage waveform , B Beam intensity depends on the atomic number of the target, tube current, kV and kV waveform, D No characteristic K shell radiationis produced from a Tungsten target at kVp 65, E After 2.5mm of aluminium filtration, the peak intensity of an x-ray beam occurs about 1/3 of the maximum kVp

A For a monochromatic beam attenuation is exponential, B The amount of attenuation increases as electron density increases, E The half value thickness is the thickness of a substance that will reduced the intensity of a beam by 50%

A Is defined as the linear attenuatuin coefficient (LAC) divided by the density, B Is affected by the atomic number, E Depends on the type of radiation interaction

A There is interaction between a free electron and a photon, B For incident photons of equal energy, more energy is lost from the photon as the scatter angle increases, C High energy radiation undergoes more scattering events than lower energy radiation, D The amount of scattering that occurs depends on the electron density of the scattering material, E The larger the angle through which the photon is scattered, the more energy it loses.

C The photon undergoes a change in direction

B A moving grid, C Conning, E Placing a thin sheet of zinc on the film cassette

A With a parallel grid, cut-off limits the maximm field size, B With a focused grid, cut-off limits the range of focus to film distance, D Use of a grid may increase patient dose by a factor of 4.

A The interspace may be filled with aluminium, B The grid ratio is defined as the ratio between the height of the lead strips and the distance between them., C The interspace are usually much thicker than the lead strips, D In the linear grid it may be possible for the x-ray tube to be angled without the effect of "grid cut off"

C An increase in the exposure to the patient, D A higher mean energy of the beam reaching the film, E A reduction of scatter radiation reaching the film

B Should be used within a defined range of focus to film distance, C Requires an increase in patient dose to achieve the same film density as an exposure without a grid, E Improves contrast by reducing the amount of scattered radiation reaching the film

A Adding a 2mm aluminium filter to the beam, B Using a higher kVp, D Using rare earth screen

A Usual grid ratio is 4:1 - 16:1 B As grid height increases, resolution of the image improves C Grid factor is the ratio of incident radiation to transmitted radiation D They absorb both primary and secondary radiation E Grid ratio is the ability of the grid to stop primary radiation, A True B True: As grid height increases, more scattered radiation is stopped and resolution improves. However, primary radiation is also stopped and so a higher dose incurred. C False: Grid factor is the ratio of exposure needed with a grid/exposure needed without a grid. The usual ratio is 2-6 D True E False: This is primary transmission

A True: The penumbra is a consequence of the focal spot. The penumbra is the zone of unsharpness that represents the area at which the margins caused by many point sources of x-rays in the focal spot overlap. B True: Any motion of the x-ray tube components or patient contribiutes to motion unsharpness. C False: Absorption unsharpness is caused by attenuation around the object being imaged - not the focal spot D False: Due to the anode heel effect, the intensity of radiation varies across the face of the focal spot. E True

A True: Blooming (increasing in focal spot size) occurs when there is an increase in mA or low kV, especially noticeable with small focal spots. B False: Resolution is measured with a star test pattern. Focal spot size is measured with pinhole imaging. C False: This has no impact on the focal spot size. D False E True

A True B False C True D True E True

A False: Scatter is not removed. The scatter that misses the film does not contribute to the image but scatter which doses not lie obliquely contributes to the image. B True: With a gap of less than 30cm, too much scatter reaches the film to be a valued technique. C False: Grid require a higher patient dose than air gap D False: Grids are not used on paediatric patients due to the need for a higher exposure. E True

A True: The x-ray tube and the cassette move in a fixed arc in opposite directions relative to each other, but centred around the object of interest. B False: A large swing angle produces a thinner slice C True: Peripherally tissue are blurred with the object of interest in focus. However this reduces contrast. D True E True

A True B False : Structure at right angles appear more blurred than those parallel to the film C False : It is most useful when imaging structure with high inherent contrast D False E True

A True B False: Tissue contrast is enhanced. Narrow angle tomography is preferred when imaging tissue of low inherent contrast. C False: Decreased D False: Decreased E True: This can be compensated for by using multidirectional tomography

A False: Rotating the anode makes no difference to the size of the focal spot B True: Heat is spread over the track of the rotating anode. It can withstand much larger exposures without focal spot damage. C True: A stationary anode allows only slow heat removal by conduction, restricting the maximum exposures that can be made. Stationary anode tubes are only used now for intra-oral dental sets and some mobile unites. D False E False: The anode can be made from rhodium and the target from both molybedenum or rhodium in mammography

A False: It is made of molybdenum which is a poor thermal conductor. B True C False: Heat is lost mainly by radiation. It cannot be removed by convection as the rotating anode lies within vacuum. D False: If a high current is used, heat is removed more efficiently E True

A False: Inherent filtrationis the abosorption of x-rays within the x-ray tube B False: Filtration increases the mean energy of the beam therefore decreasing tissue contrast. C False: Aluminium atomic no is 13 and copper 29 so copper attenuates x-rays more by photoelectric effect. D False: Maximum photon energy stays the same- filtration prefentially filters lower energy photons that results in a higher mean energy. E False: Filtration increases the loading on the tube because it increases the mean photon energy, so giving higher output intensity.