 |
BPH702S - BIOMEDICAL PHYSICS - 1ST OPP - NOVEMBER 2023 |
|
|
1 Page 1 |
▲back to top |
nAmtBIA UntVERSITY
OF SCIEnCE AnDTECHnOLOGY
FacultyofHealth,Natural
ResourceasndApplied
Sciences
Schoolof NaturalandApplied
Sciences
Departmentof Biology,
ChemistryandPhysics
13JacksonKaujeuaStreet T: +264612072012
PrivateBag13388
F: +264612079012
Windhoek
E: dbcp@nust.na
NAMIBIA
W: www.nust.na
QUALIFICATION : BACHELOR OF SCIENCE (MAJOR AND MINOR)
QUALIFICATION CODE: 07BOSC
COURSE: BIOMEDICAL PHYSICS
DATE: NOVEMBER 2023
DURATION: 3 HOURS
LEVEL: 7
COURSE CODE: BPH702S
SESSION: 1
MARKS: 100
FIRST OPPORTUNITY: EXAMINATION QUESTION PAPER
EXAMINER: DR VAINO INDONGO
MODERATOR: DR ROSWITA HAMUNYELA
INSTRUCTIONS:
1. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIAL:
Non-Programmable Calculator
ATTACHEMENT
Periodic Table
This paper consists of 5 pages including this front page and a Periodic Table.
|
|
2 Page 2 |
▲back to top |
QUESTION 1
[20]
1.1 Briefly discuss the following terms:
(i) Oncology
(2)
(ii) Computed tomography
(2)
(iii) Radiotherapy
(2)
1.2 The concentration of blood passing through a vein in a human body has a diffusion constant
(D = 1.4 E-2 m2Is). The radius and length of the vein are given as 0.08 m and 0.15 m
respectively. Hint: (Ks= 1.3806 E-23 m2.kg.s-2.K-1, T = 400 K).
(a) Compute the gradient of concentration given that C2 = 25 kg/m3 and C1 = 80 kg/m3•
(4)
(b) Estimate the coefficient of viscosity of blood.
(4)
1.3 In medical physics field, scientists apply physics concepts, theories and methods to healthcare.
Stipulate four (4) physical applications applied to life sciences in medical imaging
techniques.
(4)
1.4 Stipulate two main applications of biomechanics?
(2)
QUESTION 2
[20]
2.1 Derive Bernoulli's equation P + ! pv 2 + pgh = constant.
(6)
2
2.2 A pipe has one end/side positioned on level (h1) and the other is tilted upward at a height h2.
The pressure values of fluid within this pipe, both on level and up, are measured as P1 and P2,
respectively. If the fluid flow is kept at steady flow, show that the height of the fluid on the
= tilted end of pipe is given by h2
Pi -Pi. Which pressure is greater?
pg
(8)
2f Page
|
|
3 Page 3 |
▲back to top |
2.3 Study the diagram below (Figure 1). Assume liquid in a container behaves as an ideal fluid.
The pressure of still fluid inside the container and pressure of flowing fluid are the same as
atmospheric pressure. A small hole is at level (2), height y2 and the water level at (1) drops
= slowly at height y1 (v1 = 0). Prove that v2 .J2gh.
(6)
(1) Point on surface of liquid
Yl• , J
Y2
v2 =?
1
m.s-
(2) Point just outside hole
Figure.]
QUESTION3
[20]
3.1 The average velocity of ultrasound in soft tissue is l.54E3 mis. Is the value higher, smaller or
similar to velocity values in bone and in lung or air. Justify your answers.
(2)
3.2 A continuous pulse of ultrasound beam with frequency of 5.00E9 Hz was used on the patient
to measure the size of a fetus. Assumption is that the patient's organ is a soft tissue (p =
l.00 9fcm3).
Estimate the wavelength (11.o)f the beam and acoustic impedance (Z).
(3)
3.3 Explain, in short, the purpose of the gel on the patient's skin during ultrasound medical
1magmg.
(2)
3IPage
|
|
4 Page 4 |
▲back to top |
3.4 Study the following diagram (Fig. 3) depicting a ultrasound beam transversing through two
media (I & 2). Pi, Pr and Pt are incident, reflection and transmitted pressure amplitudes,
respectively.
Pi--.-.-· -- Medium!
Medium2
Pr ..
Zz = PzVz
Boundary
x=O
Figure 2
(i) If the ultrasound beam has wave functions k1 and k 2 for media I and 2, write down the
expressions for incident, reflected and transmitted acoustic pressures.
(3)
(ii) Show the expressions for the acoustic velocities in the two media using the wavefunctions
as in (i).
(3)
(iii)Apply the principle of boundary conditions to show that Z1 = Pi/ui = - Pr/Ur
= andZ 2 Ptj Uc·
(7)
QUESTION 4
[20)
4.1 Identify the nucleus that produces nuclear magnetic resonance signals used to take an image
of a human body?
(2)
4.2 A group of spins was placed into a magnetic field with 5 and 20 number of spins in the lower
and upper energy levels, respectively. Calculate the energy difference M between the spin
states; k is Boltzmann's constant, I.3805E-23 JK 1; and the temperature is 27°C.
(7)
41Page
|
|
5 Page 5 |
▲back to top |
4.6 A magnetic field of 4.5 Twas passed through a nucleus of a hydrogen atom, 1H. Also a X-ray
photon (f = 2.5E19 Hz) was passed through the same atom.
Hint: Planck's constant h = 6.626E-34 Js
(i) Compute the energy of a 2.5El 9 Hz photon?
(3)
(ii) Calculate the energy of the photon that will be absorbed by a 1H nucleus (y = 4.258£7
Hz/1) in a magnetic field?
(4)
5.3 The net magnetization of magnetic resonance imaging (MRI) is set equal to zero, how long
will it take for the net magnetization to recover to 80% of its equilibrium value on a sample
which a T1 of 1.0 seconds?
(4)
QUESTION 5
[20]
5.1 State two types of x-radiations and discuss how they are produced in the x-ray tube.
(6)
5.2 During radiographic imaging techniques, the quality of an image is improved by using filters,
increasing the tube voltage, increasing the tube current and/or utilizing a target material with
high atomic number Z. For a scan that was carried around an organ of a patient by a
radiographer at a particular X-ray centre, the potential difference on the x-ray tube was 150
keV.
Sketch the diagram of Relative filtered intensity vs Photon energy showing two characteristic
x-rays on high energy values of the highest peak.
(4)
5.3 Briefly discuss the following terms;
(i) Effective dose
(2)
(ii) Linear Energy Transfer (LET)
(2)
5.4 A 99mTc generator is in transient equilibrium. The activity of Mo-99m at time to is 16 mBq.
After 156 hrs the activity of 99Mo is 3.2 mBq since there was no milking took place. Estimate
the activity of the daughter nuclide. Note: 99Mo, T112= 67 hr and 99mTc, T112= 6.05 hr. (6)
END
SI Page