X-ray and Computed Tomography - Medical Imaging Systems - Biomedical Engineering Previous Year Questions

1

2020 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2020

In diagnostic X-ray imaging, the following is NOT a part of primary EM radiation interaction in soft tissue.

A

Photoelectric effect

B

Characteristic radiation production

C

Compton scattering

D

Pair-production

Check answer

Open complete paper

2

2020 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2020

A chest radiograph of 36 cm × 48 cm is digitized. If we want to preserve details in the image to a spatial resolution of 6 cycles/mm, the approximate image data size in MB for an 8 bit quantization is __________ (rounded off to two decimal places).

Check answer

Open complete paper

3

2020 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2020

An X-ray radiography scenario is shown in the figure. If the number of incident photons (N_i) is equal to 2 × 10⁶ at 50 keV, the number of photons (N_d) that exit the tissue is __________ × 10⁶ (rounded off to two decimal places).
(use linear attenuation coefficient for soft tissue and blood at 50 keV as 0.4 cm⁻¹ and 0.2 cm⁻¹, respectively).

Check answer

Open complete paper

4

2021 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2021

Which of the following statements are CORRECT in the context of planar X-ray imaging?

A

Using fast X-ray screen improves spatial resolution

B

Using fast X-ray screen worsens spatial resolution

C

Decreasing tube current decreases signal to noise ratio

D

Decreasing tube current increases signal to noise ratio

Check answer

Open complete paper

5

2021 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2021

A radiographic system is using X-ray tube operating at 80 kVp. In order to filter the low energy X-rays, an aluminum (Al) filter of 2.5 mm thickness is used. The Al filter is replaced with a copper (Cu) filter to have the same energy filtered. The mass attenuation coefficients of Al and Cu at 80 kVp are 0.02015 m²/kg and 0.07519 m²/kg, respectively. The densities of Al and Cu are 2699 kg/m³ and 8960 kg/m³ respectively. The thickness of the new Cu filter is ______ mm. (rounded off to two decimal places)

Check answer

Open complete paper

6

2022 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2022

Backscattered electron detector of a scanning electron microscope is used to

A

study surface topography of the sample

B

quantify surface roughness

C

measure atomic number

D

contrast areas with different chemical compositions

Open complete paper

7

2022 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2022

The 1st generation (1G) CT scanner uses a point X-ray source and a detector. The source detector assembly can move linearly at a speed of 0.5 m.s⁻¹ and that it takes 0.5 s for source-detector assembly to rotate one angular increment, regardless of the angle.
This scanner is expected to collect 360 projections over 180° of span. The field of view used for data collection has a diameter of 0.5 m. The scan time required is ______ s.

Check answer

Open complete paper

8

2022 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2022

The inverse square law has a very practical use in radiography. While taking an acceptable chest radiograph of a subject at a distance of 0.75 m from the X-ray generator, X-ray source settings were kept at 50 kVp, 50 mA.s.
If the subject is moved to a distance of 1 m, and the kVp is kept the same, the new value of mA.s to obtain the same exposure will be ______ mA.s (rounded off to two decimal places).

Check answer

Open complete paper

9

2023 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2023

A polychromatic beam of X-Rays has an energy spectrum as shown in Figure P below. Which of the following graphs (in the options A to D) depicts the energy spectrum after passing through a human body? In each figure, the horizontal axis represents Energy in keV and the vertical axis represents Relative X-ray Intensity.

A

B

C

D

Open complete paper

10

2023 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2023

A circular disc of radius \(R\) (in cm) has a uniform absorption coefficient of 1 cm\(^{-1}\). Consider a single ray passing through the disc in the plane of the disc. The shortest distance from the center of the disc to the ray is \(t\) (in cm). If \(I_i\) is the intensity of the incident ray and \(I_o\) is the intensity of the transmitted ray, then \(\log\left(\frac{I_i}{I_o}\right)\) is given by __________.

A

\(2\sqrt{R^2 - t^2}\)

B

\(2R\)

C

1

D

\(2\sqrt{R - t}\)

Open complete paper

11

2023 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2023

A normally incident X-ray of energy 140 keV passes through a tissue phantom and is detected by the detector as shown in the figure below. The phantom consists of tissue P with an absorption coefficient of 1 cm\( ^{-1} \) and a thickness of 1 cm, and tissue Q with an absorption coefficient of 10 cm\( ^{-1} \) and a thickness of 2 cm. Calculate the intensity (in \( \mu \)eV) detected by the detector. (Round off the answer to one decimal place.)

Check answer

Open complete paper

12

2023 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2023

A two-dimensional square plate (20 mm sides) contains a homogeneous circular inclusion of 5 mm diameter in it. A parallel beam of X-rays (beam width 30 mm) is used in a tomography system to determine the location of the inclusion. What is the minimum number of views required to approximately determine the location of the inclusion?

Check answer

Open complete paper

13

2024 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2024

Which one of the following events is NOT typically encountered in diagnostic X-ray projection radiography?

A

Pair production

B

Photoelectric absorption

C

Compton scattering

D

Characteristic radiation

Open complete paper

14

2024 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2024

A monochromatic beam of \(\gamma\)-ray photons is incident on a homogenous tissue. Which of the following relationships hold(s) TRUE for the half-value layer thickness?

A

The first half-value layer is thicker than the second half-value layer.

B

The second half-value layer is thicker than the first half-value layer.

C

All the half-value layers have equal thickness.

D

The ratio of thickness of the first and second half-value layers change based on the intensity of the incident beam.

Open complete paper

15

2024 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2024

The X-ray attenuation coefficients as a function of photon energy for three materials are shown in the figure below. A tissue phantom containing these three materials is imaged at two different X-ray photon energies of 50 keV and 150 keV. When the developed X-ray film is viewed, which of the following statements is/are TRUE?

A

Bone will appear relatively brighter than DCA in 50 keV.

B

DCA will appear relatively brighter than bone in 50 keV.

C

Bone will appear relatively brighter than DCA in 150 keV.

D

DCA will appear relatively brighter than bone in 150 keV.

Open complete paper

16

2024 · Biomedical Engineering · Medical Imaging Systems · X-ray and Computed Tomography

Biomedical Engineering (BM) 2024

An X-ray beam of initial intensity I\(_0\) of 70 keV imaging the chest is assumed to undergo attenuation through the muscle tissue for a thickness of 16 cm and further through the bone tissue for a thickness of 4 cm. The half value layer (HVL) thicknesses for the muscle and bone are 3.5 cm and 1.8 cm, respectively. The percentage of X-ray intensity transmitted through the body is ______. Give your answer rounded off to 2 decimal places.

Check answer

Open complete paper