Physics & Haemodynamics Theory Exam May 2009

A new Forum for candidates taking the Physics & Haemodynamics theory exam in May 09.
Need Help or support?
Use this Forum to communicate with fellow candidates!

The Forum will be supported by the exam coordinator who will advise and help where possible
and set practice questions every couple of weeks !!!!!!!!

So visit regularly......

Sorry about the delay in getting some questions up - I wasn't sure anyone was using the site!
I'll try to get a few a week on...though not necessarily multiple choice.

My experience has shown that maths & equations is a usually a stumbling block for people so let's start with that.

1. The speed of blood in an artery is 0.5m/s. A 5MHz transducer is used and the beam is steered at an angle of 60o. What is the detected Doppler frequency (in kHz)?

2. The PRF of the system is 5kHz. What is the maximum Doppler frequency that can be unambiguously detected?

3. The cross-sectional area of an artery is 0.3cm2 and the average velocity is 50cm/s. What is the average flow-rate in mL/s? (clue: 1cm3 = 1mL)

4. The height difference between the right atrium and the foot is 1.2m. What is the hydrostatic pressure (relative to the heart) in the foot on standing? (Blood density, ρ = 1060kgm-3, gravity, g = 9.81ms-1. Clues: 1mmHg=133.3Pa=133.3Jm-3). Give your answer in mmHg.

5. What is the kinetic energy density (jm-3) in an artery with a velocity of 0.6m/s?

6. What is the static filling pressure of a typical person in mmHg?

7. What is the typical range of dynamic pressure in a normal person in mmHg & Jm-3?

8. Assuming a long straight horizontal tube with no heat losses etc. Just upstream from a stenosis there is a dynamic pressure of 150mmHg and a PSV of 50cm/s. What is the dynamic pressure within a stenosis if the PSV has increased to 400cm/s?

9. What is the pressure difference along a 10cm section of artery with a radius 0.3cm where the mean velocity of flow is 20cm/s. (Blood viscosity μ = 4mPa s or 4gm-1s-1).

10. What is the pressure difference along a 10cm section of artery with a radius 0.3cm where the volume flow-rate is 10mL/s?

Enjoy ! If you'd like to Fax your answers I'll happily mark them, point out any mistakes and fax them back to you. 0117 342 2443.

Hi Theresa, I think this is great and will be a potential great source of mutual help and support for the candidates.I will pass the word to the couple of people I know who are sitting the exam. Is there any mileage in emailing those you know are registered so they can all take advantage of your support in this way? Thanks for organising this. Rachel

Well done to all of those who reponded to the previous questions. Just by having a go shows you're concentrating on your revision which means you're halfway there.

1. If the PRF is 10kHz, calculate the duty factor for a 4-cycle 10MHz transmission pulse.
2. With a depth setting of 70mm and 400 scan lines, what is the frame rate?
3. A 7.5MHz transducer is used and the beam is steered at an angle of 60o. The measured Doppler frequency is 5000Hz. What is the speed of the blood flow? What is the maximum PFR that can be used without aliasing?
4. If the acoustic impedance of a material is 6x106 Rayls and the bulk modulus is 24x109 Kg/m/s2, what is the density of the material?
5. If the density of a material is 4000g/m3 and the speed of sound in it is 600m/s, calculate the Bulk modulus.
6. A sound wave travels through the above tissue and then hits another tissue which has an acoustic impedance of 3.5x106kg/m2/s and a speed of sound of 2000m/s. What percentage is reflected?
7. Assuming the above tissues, if the angle of transmission is 45o, what is the angle of incidence?
8. Assuming a 4MHz transducer with element radius of 0.2mm and the focus set to 3cm. What is the wavelength in soft tissue (in mm)? What is the near field length? What is the beam divergence? What is the beam width at the focus point?
9. If the attenuation coefficient of a tissue is 0.6dB/cm/MHz, what is the attenuation at a depth of 30mm with a 6MHz transducer?
10. The intensity of a wave passing through a circular area is 350mW/cm2 and the power of the wave is 0.032W. Calculate the diameter of the circular area.

As before if you'd like to Fax your answers I'll happily mark them, point out any mistakes and fax them back to you. 0117 342 2443.
But you need to get back to me before Thursday 14th May....

Good luck everyone! Teresa.