Radiology

Question 1

How do you differentiate a fracture from a growth plate on x-ray?

Answer 1

Fracture = jagged line

Growth plate = straight line

Question 2

What 3 factors determine absorption of an x-ray beam?

Answer 2

Thickness of tissue. Density of tissue. Atomic number of a tissue to the 4th power.

Question 3

What does doppler ultrasound allow you to image?

Answer 3

Blood flow

Question 4

Is the wavelength of x-rays shorter or longer than visible light?

Answer 4

Shorter

Question 5

What percentage of inpatients have some sort of imaging at RMH?

Answer 5

95%

Question 6

What is the unit of measurement of the absorption of a voxel?

Answer 6

Hounsfield unit

Question 7

What do ultrasound waves reflect off?

Answer 7

Tissue interfaces

Question 8

Which has better spatial resolution: CT or x-ray?

Answer 8

X-ray

Question 9

What are the 4 essential things to have the Pt do when taking a CXR?

Answer 9

Full inspiration, erect, PA, scapula out of the way

Question 10

When windowing a CT, what determines the contrast of the image?

Answer 10

Window width

Question 11

What are 3 advantages of x-radiography over CT?

Answer 11

Cheaper, less ionising radiation and better spatial resolution

Question 12

What is the most common radioisotope used in gamma ray imaging?

Answer 12

Technetium

Question 13

What is the advantage of gamma ray imaging?

Answer 13

Functional imaging

Question 14

How much stronger is a 1.5T MRI machine than the Earth’s magnetic field?

Answer 14

30,000 times greater

Question 15

How is iodine intravascular contrast medium excreted?

Answer 15

Kidneys

Question 16

What type of wave does ultrasound use?

Answer 16

Very high frequency sound waves