Radiology

Question 1

what kind of radiation do X-rays use?

Answer 1

atomic electrons

Question 2

what kind of radiation do CT scans use?

Answer 2

X-rays - atomic electrons

Question 3

what does ultrasound use?

Answer 3

sound waves

Question 4

what does magnetic resonance use?

Answer 4

radiofrequency

Question 5

where do gamma rays originate?

Answer 5

atomic nucleus

Question 6

what does radiation interaction with matter depend on?

Answer 6

energy of radiation and the density and composition of the matter

Question 7

what is projection imaging x-rays?

Answer 7

generate x-rays, they are transmitted back, and you use radio-opaque contrast media like barium to help visualize structures

Question 8

what is fluoroscopy radiography?

Answer 8

real-time imaging X-ray - live feed

Question 9

how does tissue density equate to X-ray film

Answer 9

the more dense the tissue (bone) the whiter the color

Question 10

benefits and drawbacks of transmission x-ray?

Answer 10

benefits: low cost, low dose, low risk, high resolution
drawbacks: need multiple projections, limited number of views, can’t see behind stuff

Question 11

what is computed tomography?

Answer 11

X-ray source rotates around patient - get hundreds of “films” that put together a 3D picture
helical/spiral
get one slice

Question 12

what is multiple detector CT (MDCT)?

Answer 12

multiple slices are obtained from the CT

Question 13

what is multiple source CT?

Answer 13

use two x-ray sources with different energy levels to allow simultaneous acquisition of two different images with different contrast

Question 14

what are the benefits and drawbacks to CT?

Answer 14

fast scanning, can see behind structures

drawbacks: limited soft tissue contrast, higher patient dose

Question 15

what is nuclear medicine emission?

Answer 15

molecular tracers tagged with radioactive atoms - actively take up the tracer and wait for uptake and non-specific clearance - capture emission with gamma camera

Question 16

what is single photon emission computed tomography?

Answer 16

a single photon travels through the body and deposits in camera - YOU are radioactive, you see where the tracer/photon went

Question 17

what are some common radioisotopes?

Answer 17

iodine-123, indium-111, thallium-201, technetium-99m

Question 18

compare NM to CT?

Answer 18

NM is more sensitive, but has a lower resolution

Question 19

what is PET imaging?

Answer 19

take up a positron emitter orally or IV, proton annihilates with electron to form 2 photons traveling in opposite directions - these photons interact in tissue, use a coincidence counter (intrinsically quantitative)

Question 20

what is the most commonly used tracer for PET?

Answer 20

FDG (fluorodeoxyglucose)

Question 21

what kind of tissue is MRI good for?

Answer 21

soft tissue

Question 22

is MRI ionizing or non-ionizing radiation?

Answer 22

non-ionizing, uses radio frequency

Question 23

how does ultrasound work?

Answer 23

transducer produces high frequency mechanical pressure waves coupled to surface using gel; reflected waves is detected by transducer

Question 24

what is doppler ultrasound used for?

Answer 24

detecting blood flow

Question 25

which has best contrast?

Answer 25

PET, MRI, SPECT

Question 26

which has not so good contrast?

Answer 26

radiography, CT, ultrasound

Question 27

which has best resolution?

Answer 27

radiography, CT, ultrasound

Question 28

which has not so good resolution?

Answer 28

SPECT, PET, MRI