MOCK Flashcards

1
Q

The weak nuclear force binds the nucleons together in the nucleus

A

False. (The strong nucleae force binds nucleons together in the nucleus)

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2
Q

The weak nuclear force is responsible for beta decay

A

True

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3
Q

The letter ‘A’ is used to denote atomic number

A

False. (The letter A is used to denote the mass number. The letter Z is used to denote atomic number.)

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4
Q

An alpha particle contains 2 protons and 2 neutrons

A

True. (An alpha particle is a helium nucleus, consisting of 2 protons and 2 neutrons)

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5
Q

Beta particle (B-) emission from a nucleus involves the conversion of a proton to a neutron

A

False. (B- emission involves the conversion of a neutron into a proton)

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6
Q

Technetium 99m is the main radioisotope used for imaging

A

True. (Its popularity arises from its ideal characteristics eg. 6hr half life)

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7
Q

Technetium 99m is produced in a cyclotron

A

False. (Tc99m is produced from Mo in a technetium generator. Fluorine-18 is produced in a cyclotron)

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8
Q

A typical administered activity for an isotope bone scan would be 500 becquerels

A

False. (It is typically much higher. Usually measured in MEGAbecquerels)

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9
Q

The use of a collimator increases the sensitivity of a gamma camera

A

False. (The use of a collimator decreases the sensitivity of a gamma camera by reducing the overall number of gamma rays that reach the detector)

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10
Q

Molybdenum is produced in a cyclotron

A

False (It is most commonly produced in nuclear reactors. Fluorine-18 is produced in a cyclotron)

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11
Q

Molybdenum breakthrough cannot be measured with a well counter

A

False. (Molybdenum breakthrough CAN be measured with a well counter)

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12
Q

Gallium67 is the main isotope used in lung perfusion scans

A

False. (Tc-99m MAA is most commonly used in lung perfusion scans)

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13
Q

The patient should be positioned as far away from the collimator as possible to improve extrinsic resolution

A

False. (The patient should be positioned AS CLOSE AS POSSIBLE to the collimator ro improve extrinsic resolution)

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14
Q

The collimator in a gamma camera is not used for an isotope bone scan

A

False. (The collimator IS used for an isotope bone scan)

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15
Q

A collimator improves the spatial resolution of a gamma camera

A

False

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16
Q

The use of a collimator increases the sensitivity of the gamma camera

A

False. (The use of a collimator decreases the sensitivty of a gamma camera)

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17
Q

The collimator in a gamma camera can help to reduce scatter

A

True. (Although it is not its main function, it does reduce scatter)

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18
Q

The size of the aperture of an ultrasound probe is directly related to the length of the near field

A

True

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19
Q

The speed of the ultrasound waves in bone is faster than soft tissue

A

True

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19
Q

Ultrasound is a form of electromagnetic wave

A

False.

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20
Q

In Ultrasound, The spatial pulse length (SPL) determines axial resolution

A

True

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20
Q

In ultrasound, the velocity in soft tissue is approximately 1500 ms-1

A

True

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20
Q

Sound waves can travel in a vacuum

A

False. (Sound waves need a medium to pass through)

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21
Q

Matching the acoustic impedance of two media will insure maximum reflection of the ultrasound beam

A

False. (BIG DIFFERENCES in acoustic impedance will result in strong reflection - impedances should be matched to allow for minimal reflection)

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21
Q

Typical ultrasound absorption in tissue is approximately 10dB per cm per MHz (10dB cm-1 MHz-1)

A

False. (It is 1dB per cm per MHz)

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21
Q

The thickness of the piezoelectric crystal is one quarter of the wavelength of the emitted ultrasound wave

A

False. (Crystal thickness is half the wavelength of the US beam)

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22
Q

Axial resolution is superior to lateral resolution

A

True

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23
Q

A Doppler Ultrasound transducer uses a long spatial pulse length

A

True. (Doppler imaging uses a longer SPL than normal u/s as this results in a narrower bandwidth)

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24
Q

The pulse repitition frequency (PRF) can be ignored during Doppler ultrasound

A

False. (PRF is critical to Doppler as it affects the ability to measure velocity)

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25
Q

In MRI, slice thickness is determined by the steepness of the slice selection gradient

A

True. (and also by the bandwidth of the RF pulse)

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26
Q

T1 is called the longitudinal relaxation time constant

A

True

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27
Q

In MRI, the value of T1 is independent of the magnetic field strength

A

False. (The value of T1 DEPENDS on magnetic field strength B0 - T2 does not)

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28
Q

The Mz magnetisation vector recovers fully in a time of twice the value of T1 following a 90 degree pulse

A

False. (The full recovery of Mz takes much longer - about 5 times the value of T1)

29
Q

Quenching is a common problem in a resistive magnet scanner

A

False. (It is more commonly a problem in SUPERCONDUCTIVE magnet scanners)

30
Q

Gradient echo sequences have better SNR than conventional Spin Echo sequences

A

False. (GE sequences have reduced SNR)

31
Q

Fast spin echo sequences reduce scan time by not using 180 degree rephasing pulses

A

False. (FSE uses multiple 180 degree rephasing pulses - this allows for the acquisition of multiple echos in a shorter amount of time)

32
Q

A STIR sequence is used for suppression of the signal from fat

A

True

33
Q

The noise produced in an MRI unit is due to the vibration of the surface coils.

A

False. (The noise is produced due to the GRADIENT coils)

34
Q

A hip replacement causes susceptibility artefact on an image

A

True

35
Q

Mascara should be removed prior to an MR scan of the orbits or brain

A

True. (Many mascaras contain metallic particles that could interfere with the magnetic field)

36
Q

The use of gadolinium contrast agent lengthens the T1 value of tissues

A

False. (Gd SHORTENS both T1 and T2 of tissues.)

37
Q

T2 values for tissue are independent of the strength of B0

A

True.

38
Q

Tissue heating from the RF pulse is more of an issue with low field strength magnets

A

False. (Tissue heating from the RF pulse is more of an issue with high field strength magnets)

39
Q

Inversion recovery sequence cannot be used to produce a T1 weighted image

A

False. (In fact, IR sequence is used if strong T1 weighting is required.)

40
Q

The Echo Train Length in a FSE sequence is a measure of the number of 90 degreee pulses used within the Tr time interval.

A

False. (The ETL is a measure of the number of 180 degree pulses and their corresponding echos.)

41
Q

The projectile effect is not a safety issue with low field strength MR scanners

A

False. (It depends on the rate of change of the magnetic fielld, rather than field strength. Therefore low field strength magnets are just as dangerous.)

42
Q

The frequency encoding step is the time limiting factor in the production of an MR image

A

False. (It takes very little time to do the frequency encoding. The phase encoding steps are the rate limiting factor.)

43
Q

The central lines in k-space contain most of the spatial resolution information contained in the image.

A

False. (Image contrast resolution is determined by the central lines. Spatial resolution is determined by the peripheral lines.)

44
Q

Chemical shift artefact of the second kind is seen in Spin Echo sequences.

A

False. (This only occurs in GE sequences)

45
Q

There is a risk of patient asphyxiation with quenching of the magnet.

A

True

46
Q

Specific Absorption Rate (SAR) can be ignored in abdominal MR scans

A

False. (SAR cannot be ignored.)

47
Q

Half Fourier scanning improves the SNR

A

False. (It shortens imaging time at the expense of SNR)

48
Q

Wrap around artefact can be removed by reducing the FOV

A

False. (FOV needs to be increased to prevent wrap around artefact.)

49
Q

PET has a better spatial resolution than conventional nuclear medicine imaging

A

True

50
Q

In PET, the main isotope used is FLuorine-18

A

True

51
Q

Shielding requirements for PET are similar to that needed for a gamma camera installation

A

False. (Shielding requirements for a PET scan room are much higher)

52
Q

In FDG PET imaging, uptake of the tracer is highest in metabolically inactive cells.

A

False. (Uptake of FDG is highest in metabollically active cells.)

53
Q

The spatial resolution of a PET scanner is superior if we use Ga-68 rather than Fluorine-18

A

False. (F-18 typically provides better spatial resolution)

54
Q

Filtered Back Projection can be used to reconstruct the image

A

True

55
Q

Bismuth germanate is used as a scintillator in a PET scan

A

True. - ? not much anymore

56
Q

Unlike SPECT, tissue attenuation correction is not needed in PET-CT

A

False. (Attenuation correction is needed in both SPECT and PET)

57
Q

PET CT scanners use a half ring of detectors

A

False. (They use a full circular ring of detectors)

58
Q

PET CT uses continuous table movement during the scan

A

False. (It moves a ‘block’ at a time)

59
Q

Coincidence events form a line of response

A

True

60
Q

Patient should be advised to exercise prior to a PET scan

A

False. (This will increase glucose metabolism in tissue)

61
Q

Time of Flight technique can be used in PET-CT

A

True

62
Q

In PET, a collimator is used to remove scattered photons

A

False. (PET imaging does not use a collimator)

63
Q

A pulse height analyser is not used in PET imaging

A

False. (A PHA is used in PET imaging)

64
Q

Patient dose from a PET-CT scan can be reduced by using a non-diagnostic CT scan as part of the imaging sequence

A

True

65
Q

Caesium Iodide is the main scintillator used in PET detector elements

A

False. (Usually LGO or GSO)

66
Q

A line of response (LOR) depicts the pathway of the positron within the tissue

A

False. (It depicts the pathway of the two gamma rays emitted following an annhiliation event)

67
Q

Photomultiplier tubes are used in PET-CT

A

True

68
Q

A typical patient dose in PET-CT would be 3-5 mSv

A

False. (Higher)

69
Q

In SPECT, a dual-headed gamma camera is used

A

True

70
Q

Technetium cannot be used in SPECT

A

False

71
Q

Collimators are not required because of geometric considerations

A

False

72
Q

In modern SPECT systems, tissue attenuation correction is done using an attached CT scanner

A

True

73
Q

In Ultrasound, the length of the near field is inversely proportional to the frequency of the transducer

A

False. (The length of the near field is directly proportional to the frequency of the transducer)

74
Q

In US, the focal plane lies within the Fraunhoffer zone

A

False. (It lies within the Fresnal zone)

75
Q

In U/S, Time Gain Control can be switched off during abdominal imaging

A

False

76
Q

Lateral resolution depends on pulse duration

A

False. (It depends on the width of the near field and the curve of the transducer surface)

77
Q
A