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Flashcards in Final Deck (58)
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1
Q

uses x-rays to present image slices

A

CT

2
Q

calculates x-rays ability to pass through or be weakened by tissues

A

attenuation coefficients

3
Q

advantage of CT

A

3-D imaging

4
Q

each image square

A

pixel

5
Q

elongated block of tissue

A

voxel

6
Q

CT thickness determined by..

A

computer programming

7
Q

pioneer of CT imaging

A

Godfrey Hounsfield, 1979

8
Q

what determines Hounsfield units (HU)?

A

x-ray attenuation coefficient

9
Q

imaging of choice for head trauma and cerebrovascular events

A

Head CT axial slices

10
Q

lymphoma and head/neck neoplasms

A

Neck CT + C

11
Q

most helpful for coronal and sagittal planes

A

MRI

12
Q

fat looks bright

A

T1 MRI

13
Q

water looks bright

A

T2 MRI

14
Q

for visualizing normal anatomy

A

T1

15
Q

used to detect disease process

A

T2

16
Q

allows spatial encoding of the MRI signal and is critical for a wide range of “physiologic” techniques

A

gradients

17
Q

receive and transmit signal

A

patient coils

18
Q

“atenna” of MRI system

A

radiofrequency (RF) coils

19
Q

MRI study is susceptible to

A

motion artefacts

20
Q

Dx infections, tumors, vascular pathology

A

intravenous contrast administration

21
Q

Dx of internal joint derangement

A

MR arthrography

22
Q

detect thromboembolic disease

A

MRA and CTA

23
Q

uses gadolinium enhanced contrast medium

A

MRI (T1)

24
Q

uses iodinated contrast medium and greater x-ray absorption

A

CT

25
Q

may cause nephrogenic systemic fibrosis (NSF)

A

gadolinium

26
Q

gradual fibrosis of skin/internal organ

A

NSF

27
Q

uses FDG to find malignancies

A

positron emission tomograhy (PET)

28
Q

electrical energy converted to burst of high frequency sounds waves (1-10) which are reflected by tissues

A

ultrasonogrophy (US)

29
Q

uses Tc99-methylene diphosphate as active agent

A

radionuclide bone scan

30
Q

3 phases of bone scans?

A
  1. inflow (2-5 s)
  2. tissue pool (5-15 min)
  3. delayed (2-4 hours)
31
Q

evaluates mineral bone density

A

DEXA

32
Q

how to maximize patient protection

A
  • minimize time
  • maximize distance
  • shielding
  • tuble filtration
  • collimate
  • patient cooporation
33
Q

ALARA

A

As Low As Reasonably Achievable

34
Q

what view for thoracic/pelvis for pediatrics to minimize radiation?

A

P to A

35
Q

rate of maturation/differ and metabolism –> cell radiosensitivity

A

1906 Law of Bergonie and Tribondeau

36
Q

amount of erergy absorbed per unit mass

A

Rad

37
Q

rate for energy transfer from ionizing to soft tissues

A

linear energy transfer (LET)

38
Q

different amount of potential bio effect for radiation sources

A

radiation weighting factor

39
Q

most sensitive age

A

3-7 FETAL weeks old

40
Q

halogenated pyrimidines, Vit K, methotrexate

A

radiosensitizers

41
Q

sulfhydrils (cysteine)

A

radioprotectors

42
Q

principle effects of ionizing radiation on living cells

A

radiolysis: irradiation of H2O –> free radicals

43
Q

most cell have overabundance of molecules

A

target theory

44
Q

DNA as direct target for x-rays

A

direct effect

45
Q

x-rays hit H2O –> ion radical –> DNA

A

indirect effect

46
Q

radiation induced cancer, leukemia, and genetic mutations are examples of?

A

non-threshold linear response

“no photon is safe”

47
Q

for making safety guidelines in radiography what is used?

A

linear non-threshold response

48
Q

leads to cell killing

A

deterministic effect

49
Q

expressed by cangerogenesis, mutations, hereditary chcanges and latent cancer

A

stoachastic effect (non-threshold effect)

50
Q

period of organogenesis

A

3-7 fetal weeks

51
Q

measures radiation exposure/intensity in air

A

roentgen

52
Q

measures how much energy is absorbed per unit mass

A

Rad

53
Q

human lethal Rad dose

A

350

54
Q

1 grey =

A

100 Rads

55
Q

unit of radiation exposure measuring potential bio effects

A

Rem

56
Q

most radiography stuff

A

.5 mSv/yr or less

57
Q

1 sievert (Sv) =

A

100 Rem

58
Q

theory based on experimental animals who received low radiation dose express better survival ability

A

hormesis