ABSTRACT
IR(ME)R negates the need for ethics approval if undertaking research involving ionizing radiation
e. Doses must be kept within diagnostic reference levels (DRLs)
7. Radiation protection: a. Irradiation of the pelvis in a pregnant female can never be justified b. Optimization of a procedure requires adequate quality
assurance (QA) c. Dose limits for staff represent a good practice guide d. Patient dose limits are higher than those for the general public e. The annual effective dose limit for a trainee less than 18 years old
is three-tenths that of an adult employee
8. Regarding image quality: a. Noise in an image can adversely affect both spatial resolution and
contrast b. A high resolution image might have 15 lp/mm c. Quantum mottle is defined as
p M, where M is the mean number
of photons detected per pixel d. Noise increases with higher signal e. An increased kV reduces subject contrast
9. Scatter: a. For radiography in the chest and abdomen, there is less scatter
radiation detected than transmitted primary beam b. Has less effect on the image with a lower kV c. Will lessen as grid ratio increases d. Is more efficiently eliminated with a moving grid e. An air gap is necessary if using a grid
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10. focal spots of less than
0.3 mm c. By rotating the anode a smaller effective focal spot is achieved d. The anode heel effect is greatest at the cathode side of the
X-ray beam e. Focal spot size is assessed with an ionization chamber
11. Quality assurance in radiography: a. Beam kV may be assessed with a sensitometer b. The equipment supplier is responsible for ensuring that a QA
programme is maintained for the life of the equipment c. Spatial resolution in fluoroscopy is assessed using a Leeds test
object d. Monitors may be tested with 13 gradations of greyscale using
standard Society of Motion Picture and Television Engineers (SMPTE) images
e. Needs only to be performed yearly
12. In mammography: a. Useful target-filter combinations include molybdenum-rhodium,
rhodium-rhodium, and rhodium-molybdenum b. The mean energy of X-rays used is in the range of 15 to 20 keV c. To utilize the anode-heel effect, the tube axis runs parallel to
the chest wall d. Heat loading of the focal spot limits exposure time e. To assess risk, mean glandular dose is used instead of
effective dose
13. Film-based radiography: a. X-ray film is more sensitive to light than to X-rays b. Caesium iodide (CsI) is the active ingredient in film which
forms the latent image c. Processing occurs independently of temperature d. An optical density (OD) of 2 means 99% of light incident on
the processed film is transmitted e. Film is no longer used in modern radiography
14. Digital imaging: a. Edge enhancement software improves spatial resolution but also
increases noise b. DICOM is the industry standard in medical imaging and is
shorthand for DIgital COMmunication c. Does not involve sampling d. With Fourier analysis fine structures have a high spatial frequency e. Aliasing occurs if the Nyquist frequency is not met
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15. for a department changing
b. Utilizes photostimulable phosphors c. Is an entirely digital process d. Has a wide dynamic range e. Generally spatial resolution is less than with film-screen systems
16. Digital radiography (DR): a. Implies imaging is achieved directly from the plate b. Can be direct or indirect, where indirect uses phosphors c. The detective quantum efficiency for DR is roughly doubled
that of CR and film-screen d. The number of pixels in the image can be increased by choosing
a smaller field of view (FOV) e. In general, overexposed images are immediately apparent when
viewed
17. Image intensifier design: a. The input screen has a diameter approximately 50 times that of
the output screen b. The input screen converts X-ray photons to light; the light
photons are then accelerated across to the output screen c. The input screen is maintained at a negative voltage d. The image on the output screen is inverted relative to the input
screen e. Within the intensifier an inert gas such as argon is used for stability
18. Regarding the image intensifier: a. The sequence of events in image formation is as follows: X-ray
photons to light, light to electrons, electrons back to light b. Gain refers to the increased resolution achieved c. Intensification occurs as a product of flux gain and minification
gain d. Magnification reduces intensification e. Automatic brightness control follows pre-programmed curves
19. Image quality in fluoroscopy: a. Continuous fluoroscopy is actually pulsed b. The patient entrance surface dose rate may be up to
200 mGymin21 to provide adequate image quality c. The quantum sink in fluoroscopy is the number of X-ray
photons incident at the input screen d. Using an X-ray field that extends beyond the edge of the
patient may result in a loss of image quality e. An image intensifier would not work properly in a room
adjacent to a magnetic resonance (MR) scanner
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20. is subtracted from
subsequent images c. Pixel shifting allows correction for movement in portions of
the image when other areas are static d. Can be used in realtime e. Leads to an increase in noise
21. Flat plate detectors for fluoroscopy: a. Use the same technology as DR b. Have improved spatial resolution when compared with the
image intensifier c. Often require magnification to maximize resolution d. Suffer from the same geometrical distortion as image intensifiers e. Remove the need for collimation
22. Regarding the computed tomography (CT) image: a. The CT number for fat is approximately 50 b. Around 4000 levels of grey are generally possible in a CT image c. Windowing limits the visible grey scale to make tissue contrast
more discernable to the human eye d. Voxel isotropy means neighbouring voxels have the same CT
number e. A tissue detail with dimensions smaller than a voxel is only
visible because of partial volume effects
23. Equipment in CT: a. Modern scanners are based on 4th generation design b. The anode-cathode axis lies parallel to the z-axis c. Thanks to slip ring technology, each 3608 rotation of the
gantry takes around 2 sec d. Focal spot heat capacity is approximately 4 MJ e. Detectors such as bismuth germinate are used
24. CT image quality: a. To ensure accurate CT numbers are produced the scanner must
be calibrated to air, water and bone b. The maximum resolution achievable on current CT scanners is
around 20 lp/mm c. Voxel noise is directly related to slice thickness d. Pitch has no effect on noise e. Noise is more apparent when using a narrower window width
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25. by administering drugs
b. Beam hardening can be partly corrected by using a copper
bow-tie filter c. Ring artefact is observed in patients with metal implants or
jewellery d. A faulty detector can result in wrap-around artefact on the
reconstructed image e. Thicker slices will give an increased likelihood of partial
volume effect
26. Regarding CT scanning: a. CT fluoroscopy is only possible since the advent of slip ring
technology b. Multi-slice CT scanners do not require the use of any beam
filtration c. Typically tube voltage is in excess of 140 kV d. Solid-state detectors such as cadmium tungstate have greater
detection efficiency than xenon gas ionization chambers e. The acquisition time of a CT head scan using a helical scanner
is typically in the region of 60 sec
27. Concerning radioactivity: a. The number of decays per second will remain constant while a
radionuclide is radioactive b. Isotopes of an element have the same mass number but may have a
different atomic number c. Radionuclides are unstable nuclei that undergo spontaneous
decay with the emission of radiation until reaching a stable state d. The exact timing of the decay of an individual atom is determined
by the chemical properties of that particular isotope e. After eight half-lives, the radioactivity of a set amount of
radioactive matter will have reduced by a factor of 64
28. Image formation with a gamma camera: a. X and Y coordinates are determined by an array of
photomultiplier tubes b. Collimators are rarely used c. Spatial resolution and sensitivity to gamma radiation cannot both
be maximized in the same study d. Scatter is reduced using the pulse height analyser e. It is not possible for gamma rays to be detected with energy
greater than that characteristic for the radionuclide
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29. at different angles to produce
b. Photon counts for the acquisition at each angle are much higher
than a single image of planar radionuclide imaging c. Opposing views allow some correction of attenuation of gamma
rays within the patient d. Is rapid enough to take an entire image within a single breath-hold e. Can be gated to image the heart
30. Positron emission tomography (PET) and PET-CT: a. PET scanners use a single detection plate which acquires about
60 images revolving around the patient b. Narrow lead or tungsten septa are used as a grid to limit the angle
of incoming photons c. The most commonly used radionuclide in PET scanning is
99Technetium metastable (Tc-99m) d. PET-CT image reconstruction includes a tissue correction
algorithm based on the CT scan e. Fusion of PET and CT images most commonly involves combin-
ing a PET and a CT scan of the same patient taken up to six months apart
31. Image quality in radionuclide imaging: a. A defective photomultiplier tube will show as a linear defect on
the image b. Electronic noise is the major limiting factor in radionuclide
imaging quality c. A converging collimator can improve resolution for objects
smaller than the area of the crystal d. Temporal resolution refers to blurring at the edges of the image e. Sodium iodide (NaI) is not used in PET imaging
32. Regarding effective dose in nuclear medicine: a. A Tc-99m bone scan is similar to a barium enema b. A cardiac scan with thallium-201 gives approximately five times
the average natural annual background radiation in the UK c. A Tc-99m lung perfusion scan is the same as the annual whole
body dose limit for a member of the public d. Effective dose can be reduced by encouraging the patient to drink
plenty of water and empty their bladder e. In men, lead groin shields should be worn to reduce the dose to the
gonads
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33. the tip of the syringe into the
b. Following administration of a radionuclide, patients should be
restricted to a room with radiation shielding on the walls c. If contaminated, simple washing of hands is not sufficient d. Some waste can be dispersed to the environment e. Spills must be cleaned up immediately
34. Sound waves in tissue: a. The speed of sound in bone is faster than the speed of sound in
soft tissue b. The speed of sound in most soft tissues is relatively independent
of wavelength and frequency c. Acceleration of soft tissue particles by the ultrasound waves never
reaches more than 10 g d. Ultrasound is an example of a transverse wave e. Ultrasound waves take approximately 7 ms to travel 1 cm
35. Piezoelectric effect and probes: a. The piezoelectric effect describes a property in which expansion
or contraction of the piezoelectric element causes or is caused by an electric voltage
b. Typical voltages applied within the ultrasound probe to transmit are in the region of 5-12 V.
