MOCK Flashcards
The weak nuclear force binds the nucleons together in the nucleus
False. (The strong nucleae force binds nucleons together in the nucleus)
The weak nuclear force is responsible for beta decay
True
The letter ‘A’ is used to denote atomic number
False. (The letter A is used to denote the mass number. The letter Z is used to denote atomic number.)
An alpha particle contains 2 protons and 2 neutrons
True. (An alpha particle is a helium nucleus, consisting of 2 protons and 2 neutrons)
Beta particle (B-) emission from a nucleus involves the conversion of a proton to a neutron
False. (B- emission involves the conversion of a neutron into a proton)
Technetium 99m is the main radioisotope used for imaging
True. (Its popularity arises from its ideal characteristics eg. 6hr half life)
Technetium 99m is produced in a cyclotron
False. (Tc99m is produced from Mo in a technetium generator. Fluorine-18 is produced in a cyclotron)
A typical administered activity for an isotope bone scan would be 500 becquerels
False. (It is typically much higher. Usually measured in MEGAbecquerels)
The use of a collimator increases the sensitivity of a gamma camera
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)
Molybdenum is produced in a cyclotron
False (It is most commonly produced in nuclear reactors. Fluorine-18 is produced in a cyclotron)
Molybdenum breakthrough cannot be measured with a well counter
False. (Molybdenum breakthrough CAN be measured with a well counter)
Gallium67 is the main isotope used in lung perfusion scans
False. (Tc-99m MAA is most commonly used in lung perfusion scans)
The patient should be positioned as far away from the collimator as possible to improve extrinsic resolution
False. (The patient should be positioned AS CLOSE AS POSSIBLE to the collimator ro improve extrinsic resolution)
The collimator in a gamma camera is not used for an isotope bone scan
False. (The collimator IS used for an isotope bone scan)
A collimator improves the spatial resolution of a gamma camera
False
The use of a collimator increases the sensitivity of the gamma camera
False. (The use of a collimator decreases the sensitivty of a gamma camera)
The collimator in a gamma camera can help to reduce scatter
True. (Although it is not its main function, it does reduce scatter)
The size of the aperture of an ultrasound probe is directly related to the length of the near field
True
The speed of the ultrasound waves in bone is faster than soft tissue
True
Ultrasound is a form of electromagnetic wave
False.
In Ultrasound, The spatial pulse length (SPL) determines axial resolution
True
In ultrasound, the velocity in soft tissue is approximately 1500 ms-1
True
Sound waves can travel in a vacuum
False. (Sound waves need a medium to pass through)
Matching the acoustic impedance of two media will insure maximum reflection of the ultrasound beam
False. (BIG DIFFERENCES in acoustic impedance will result in strong reflection - impedances should be matched to allow for minimal reflection)
Typical ultrasound absorption in tissue is approximately 10dB per cm per MHz (10dB cm-1 MHz-1)
False. (It is 1dB per cm per MHz)
The thickness of the piezoelectric crystal is one quarter of the wavelength of the emitted ultrasound wave
False. (Crystal thickness is half the wavelength of the US beam)
Axial resolution is superior to lateral resolution
True
A Doppler Ultrasound transducer uses a long spatial pulse length
True. (Doppler imaging uses a longer SPL than normal u/s as this results in a narrower bandwidth)
The pulse repitition frequency (PRF) can be ignored during Doppler ultrasound
False. (PRF is critical to Doppler as it affects the ability to measure velocity)
In MRI, slice thickness is determined by the steepness of the slice selection gradient
True. (and also by the bandwidth of the RF pulse)
T1 is called the longitudinal relaxation time constant
True
In MRI, the value of T1 is independent of the magnetic field strength
False. (The value of T1 DEPENDS on magnetic field strength B0 - T2 does not)