Computational Imaging 2024/25 spring

HW2. Biomedical Imaging (21st March, 23.59)

EX1 (1p) : What is the kinetic energy of an electron with mass 9.31 {$\times $}10{$ ^{(−31)}$} Kg moving with the velocity of light

  (a) 41 fJ 
  (b) 39.25 fJ
  (c) 40.95 fJ
  (d) 39.5 fJ

EX2 (1p) : What is the kinetic energy of a particle having a wavelength of 2pm. Plank's constant 6.6 {$\times $}10{$ ^{(−34)}$} J-sec

   (a) 99 pJ
   (b) 98 pJ
   (c) 99 fJ
   (d) None of these

EX3 (1p) : What is the Hounsfield unit of the brain where the attenuation coefficient of the brain and water is 0.237 and 0.214 respectively.

  (a) 23
  (b) 97.05
  (c) 107.48
  (d) None of these

EX4 (1p) : Identify the imaging modality

  (a) A - CT, B - T1 weighted MRI, D- T2 weighted MRI, D - T1 weighted MRI
  (b) A - T2 weighted MRI, B - CT, C- T1 weighted MRI, D - X ray
  (c) A - T1 weighted MRI, B- T2 weighted MRI, C - CT D - CT
  (d) A - T2 weighted MRI, B - CT, C - T1 weighted MRI, D - CT

EX5 (1p) : Calculate the Larmor frequency of a molecule subjected to a magnetic field of 1.5 T

  (a) 63.87 MHz
  (b) 401.11 MHz
  (c) 100.28 MHz
  (d) 28.39 MHz

EX6 (1p) : Choose the correct statement

  (a) T1 relaxation time in MRI is longer than T2 relaxation time
  (b) T2 relaxation time in MRI is longer than T1 relaxation time
  (c) T1 and T2 relaxation time in MRI are equal
  (d) T1 relaxation time in MRI can be longer or shorter than T2relaxation time

EX7 (1p) : Consider a 1.5 T MRI scanner with a slice encoding gradient of 10 mT/m. What should be the step size in scanning frequency to achieve a slice resolution of 10 mm?

  (a) 42:58 MHz
  (b) 4:258 MHz
  (c) 4258 Hz
  (d) 4258 MHz

EX8 (1p) : From the following list of ultrasound frequencies, choose the best one for imaging heart.

  (a) 20 MHz
  (b) 3 MHz
  (c) 10 MHz
  (d) 100 MHz

EX9 (1p) : Arrange the following materials in increasing order of acoustic impedance. A - Adipose tissue, B - Brain tissue, C - Compact bone, D - Liver

  (a) A<D<B<C
  (b) C<D<B<A
  (c) C<B<D<A
  (d) A<B<D<C

EX10 (1p) : Calculate the angular aperture for a lens having numerical aperture 0:5. Consider air as the medium.

  (a) 15
  (b) 60
  (c) 30
  (d) 64.4

EX11 (1p) : In optical microscopy, what kind of artifact is observed in relation with high numerical aperture?

  (a) Blurring
  (b) Saturation
  (c) Airy disk eect
  (d) None of these

EX12 (1p) : What is the relation between depth of focus and numerical aperture in optical microscopy?

  (a) No relation
  (b) Depth of focus increases with increase in numerical aperture
  (c) Depth of focus decreases with increase in numerical aperture

EX13 (1p) : What kind of microscope is used for fluorescence imaging?

  (a) Transmission light microscope
  (b) Reflected light microscope
  (c) Both transmission and reflected light microscope
  (d) None of these

EX14 Bonus (2p) : In figure shown below the {$ \mu_{1}$}, {$ \mu_{2}$}, {$ \mu_{3}$} are the attenuation coefficient of the 3 different materials given. The materials are of length {$ L_{1}$}, {$ L_{2}$}, {$ L_{3}$} respectively. Calculate the value of {$ N_{2}$}

EX15 Bonus (2p) : Consider the scheme shown in the following figure for ultrasound imaging of soft tissue. For the point P shown in the figure, find the propagation time for the j {$^{th}$} transducer for beamforming in ultrasound scanning. Assume point O to be the origin of the coordinate system and length of each transducer 1 mm. Given, {$R_{fp} = 10$}cm, {$\theta = 15 ^{o} $} speed of sound in soft tissue = 1540.

  (a) 64:46 s
  (b) 6:28 ms
  (c) 1:93 s
  (d) 6:49 ms