
The reflection of ultrasound allows the image to be generated by the ultrasound machine.

Important Questions on Medical Imaging


Determine the fraction of the intensity of an ultrasound beam that is reflected when a beam is incident normally on a boundary between water and fat. (Use values from Table )
Material | |||
Lead zirconate titanate | |||
Quartz | |||
Polyvinylidese diflouride |



(c) This is the trace formed on the screen of an oscilloscope when ultrasound is reflected from the front and rear surfaces of the head of a foetus. The time-base of the oscilloscope is set at .
(ii) Calculate the diameter of the head of the foetus.

Piezo-electric crystals have many applications other than in ultrasound scanning. For example, they are used in:
(d) the auto-focus mechanism of some cameras (to move the lens back and forth).

Represent the union of two sets by Venn diagram for each of the following.
is a prime number between and
is an odd number between and





Calculate the percentage of the incident ultrasound reflected at a muscle-soft tissue boundary.


The ultrasound image shown in Figure clearly shows the baby's skin and some bones. Explain why these show up clearly while softer organs inside its body do not.

(c) This is the trace formed on the screen of an oscilloscope when ultrasound is reflected from the front and rear surfaces of the head of a foetus. The time-base of the oscilloscope is set at .
(i) Explain why the second peak is lower than the foetus.





