Imaging

Question 1

what is an x-ray?

Answer 1

A electromagnetic packet of energy with an extremely short wavelength (0.1 - 10 nanometers)

Question 2

Describe the process of X-ray production and image capture.

Answer 2

• electron gun fires high energy electrons at a heavy atomic material (usually tungsten).
• collision creates ‘breaking radiation’ = X-rays
• directed at target being photographed
• bone absorbs rays - others hit imaging film behind
• emulsion contains silver halide - forms clumps on films upon exposure

Question 3

Why do different things appear different on X-rays?

Answer 3

• tissues absorb different amounts of radiation.

least absorption to most -
Air < fat < muscle < bone

Question 4

How does an ultrasound work?

Answer 4

fires sonic waves (sound waves)

frequency - 2-18 megahertz

Question 5

What can an ultrasound scan?

Answer 5

soft tissue - muscles, tendons, monitors embryonic development.

Question 6

what are the strengths and weaknesses of ultrasound?

Answer 6

strengths - inexpensive, portable , no long term side effects
weaknesses - has trouble penetration bone& scanning gas pockets, operator dependant,

Question 7

What is a CT scan?

Answer 7

series of 2D x-ray images around an axis of rotation, to create a 3D image.

Question 8

what are the strength and weaknesses of CT?

Answer 8

Strengths - can see lots of different planes
can differentiate between tissues of similar density

Weaknesses - reactions to contrast dye.
cancer

Question 9

What is fluoroscopy?

Answer 9

real time moving images of internal patient

xray source , fluorescent screen behind patient

Question 10

What are the strengths and weaknesses of fluoroscopy?

Answer 10

strengths - moving objections

weaknesses - patient exposed to ionising radiation and X-rays

Question 11

Describe iodinated contrast media.

Answer 11

IV radiocontrast containing Iodine
Enhances visibility.
is nephrotoxic - can result in kidney failure.
Extra fluids must be administered after to ‘flush’ system.