Lec 13 - CT/MRI Imaging Flashcards

1
Q

cone beam ct does not have nearly as much exposure as blank

A

medical ct

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2
Q

ct advantage is that it is a blank of information and NOT a standard blank

A

slice, shadow image

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3
Q

ct scans are often called CAT scans because it stands for blank

A

computed axial tomography

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4
Q

the geometry for Hounsfield’s original ct scanner used a blank beam

A

pencil

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5
Q

hounsfield found that a 2 or 3 dimensional object could be reproduced from a blank set of projections

A

infinite

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6
Q

blank from tomographic imaging are converted to 2D pixels so that data can be reconstructed into digital images

A

3D voxels

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7
Q

ct number shade of gray that is +1000

A

dense bone

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8
Q

ct number shade of gray that is 0

A

water

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9
Q

ct number shade of gray that is -1000

A

air

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10
Q

newer ct units have a ct number up to blank

A

+3000

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11
Q

spatial resolution is related to blank

A

pixel size

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12
Q

contrast resolution is related to blank

A

bit depth

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13
Q

high threshold will make everything look blank

A

black

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14
Q

3rd generation of ct design had x ray tube and detector moving on blank

A

different tracks

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15
Q

4th generation of ct design has blank moving but there was a stationary continuous ring of blank

A

x ray tube, detectors

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16
Q

to reduce effects of compton scattering in medical ct… each detector has blank… this is also important for control of blank

A

its own collimator, voxel length

17
Q

artifacts in cone beam ct are from streaks from blank

A

high density materials like implants

18
Q

3 types of tomography

A

mri, ct, pet

19
Q

most common mri target

A

hydrogen nuclei

20
Q

mri is best for blank

A

soft tissues

21
Q

mri radio frequency pulse leads to blank

A

disalignment

22
Q

mri recovery rates differ depending on the

A

tissue type

23
Q

the protons are not perfectly aligned with the magnetic field and instead are blank (wobbling) which results in a blank frequency

A

precessing, resonant

24
Q

weighted image that looks at fat and makes it bright

25
weighted image that looks at water and makes it bright
t2
26
t1 has fat with the blank t1 relaxation time
shortest
27
t2 has water with the blank t2 relaxation time
longest
28
PET scans... when labeled molecules are metabolized, blank are released which produce blank
positrons, gamma rays
29
imaging of the salivary or ductal system that usually uses iodine
sialography
30
stone in salivary gland
sialolith
31
imaging that uses sound waves and is harmless
ultrasound
32
sound is not part of the blank spectrum
electromagnetic
33
ultrasound imaging uses blank MHz
2-15
34
sound travels blank in solids than in liquids or gas
faster