3 Buckets

Question 1

3 buckets

Answer 1

Static Field
Gradient Energy
RF Energy

Question 2

Static Field Injury

Answer 2

Injury from interaction with field and object

Question 3

RF Injury

Answer 3

heating or stimulation of tissue in contact with device/implant with repeated RF pulses

Question 4

Gradient Injury

Answer 4

injury secondary to the rapid rise and fall of gradiant field pulses

Question 5

Static field Forces

Answer 5

Translational
Rotational
Lenz Effect

Question 6

Translational Force

Answer 6

greatest at end of bore
deflection of object

Question 7

Rotational Force

Answer 7

wants to align with field
spherical objects no rotation
ISO center near MAX

Question 8

Lenz Effect

Answer 8

opposition to field
size and speed determine

Question 9

Static field

Answer 9

3D around axis
symmetrical

Question 10

Fringe Fields

Answer 10

fields outside of bore
5G restricted line

Question 11

Deflection angle

Answer 11

<45 MR Conditional
>45 MR UNsafe
<45 gravity > Magnet
>45 Gravity < Magnet

Question 12

RF energy

Answer 12

decreases farther from ISO

pulse sequence dependent

Question 13

gradient energy

Answer 13

change in magnetic field

Question 14

RF Burns

Answer 14

Proximity

E Field loop

resonant circuit

reflective energy

Question 15

Proximity burns

Answer 15

tissue close to rf source

Question 16

looping burns

Answer 16

skin to skin contact

small patch

Question 17

resonant burns

Answer 17

heating of implanted devices/wires

1.5T 24-30cm

3T 12-15cm

Question 18

reflective burns

Answer 18

material reflect rf energy

\space blankets

Question 19

SAR

Answer 19

Specific Absorptino Rate

W/kg

Question 20

scan modes

Answer 20

`normal

1st level

2nd level

Question 21

Normal Mode

Answer 21

no undue physiological effect

<2 W/kg

<1 C

Question 22

1st level

Answer 22

potential burn exists

<4 W/kg

>1 C

Question 23

2nd level

Answer 23

definite potential harm

>4 W/kg

>1 C

research purposes

Question 24

1st level SAR limit

Answer 24

head 3.2W/kg 10 min

body 4W/kg 15 min

Question 25

Specific Energy Deposition SED

Answer 25

1440 J/kg shut down

Question 26

high SAR parameters

Answer 26

`SAT bands long TE short TR short echo spacing

Question 27

low Sar parameters

Answer 27

increase TR decrease echo train decrease flip angle lengthen echo spacing use gradient sequences avoid IR low gradient cycles

Question 28

B1+RMS

Answer 28

magnetic field + rotating field Root Means Squared

Question 29

RMS

Answer 29

average RF energy over time

Question 30

SED

Answer 30

total B1RMS delivered lock out 14.4 J/kg 4-24hrs

Question 31

SAR calculations

Answer 31

vary between manufacturers

Question 32

B1 RMS

Answer 32

consistent measurement non-variable part of SAR calculation

Question 33

heat dissipation

Answer 33

condution forced convection evaporation radiation

Question 34

physical heat conduction

Answer 34

dermal patches EKG leads tattoos eyeliner

Question 35

gradients TVMF

Answer 35

change of field over time strongest at bore walls

Question 36

Gradiant injuries

Answer 36

peripheral nerves stimulation magnetospheres noise

Question 37

gadient normal level

Answer 37

max rise 80% of thresh hold minimal PNS

Question 38

gradient 1st level

Answer 38

100% rise possible PNS

Question 39

gradient 2nd level

Answer 39

\>100% definite PNS

Question 40

TVMF

Answer 40

greast farther from ISO ISO least B/T=V

Question 41

guidelines

Answer 41

1982 FDA internal review board

Question 42

2002 ACR

Answer 42

whitepaper

Question 43

ACR guidance on Safe practice

Answer 43

2013