FSP Class-3 Safety

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  1. Screening
    Tech must go over the form
  2. Public - on the street
    Zone 1
  3. Zone 1
    Public - on the street
  4. Reception
    • Zone 2
    •    - insurance information is provided
    •    - feel the form
  5. Zone 2
    • Reception
    •    - insurance information is provided
    •    - feel the form
  6. Tech console area
    Zone 3
  7. Zone 3
    • Tech console area
    •    - screening
  8. Scan area
    Zone 4
  9. Zone 4
    Scan area - must screen before
  10. 5G line
    Safe limit for pace maker
  11. Safe limit for pace maker
    5G line
  12. SAR
    • Specific Absorb Rate
    • RF absorbed by blood stream and dissipated as heat.
    • Head: 3.2 Watts/kg
    • 1 gr of tissue: 8 Watts/kg
    • Whole body: 0.4 Watts/kg
    • Eyes and testes more sensitive to RF b/c do not sweat
  13. If the parameters selected for an imaging sequense will expose the Pt to SAR levels in excess of FDA defined level of no concern, they should never be employed on the Pt who are:
    Febrile seizure
  14. SAR & TR depend on Slice thickness
    Thinner slice - ↥ TR - ↧ SAR
  15. SAR - Head
    Head: 3.2 Watts/kg
  16. SAR for 1 gr of tissue:
    1 gr of tissue: 8 Watts/kg
  17. SAR - Whole body
    Whole body: 0.4 Watts/kg
  18. Shielding B0
    Steel around the wall (passive)
  19. Shielding B1
    • Faraday Cage (active - electrical)
    • use copper (best conducter)
    • exclude bad RF
  20. Magnetic Field components:
    • 1) B0 - Main Magnet (3T)
    • 2) RF - 2nd order
    • 3) Gradients - 3 pairs mini resistive:
    •    - add strength to 6T/1sec (ON/OFF)
    •    - noise from gradients
  21. Gradients
    • - 3 pairs mini resistive
    • - add strength to 6T/1sec (ON/OFF)  
    • - noise from gradients
  22. If gradients ON > 1 sec
    • 1) Peripheral Nerve Stimulator
    • 2) Arrythmic
    • 3) Magnetophosphenes - illusion of light caused when changing of MF creates current within the retina or visual cortex
  23. Magnetophosphenes
    illusion of light caused when changing of MF creates current within the retina or visual cortex
  24. What PS makes loudest noise?
    EPi - Echo Planer imaging
  25. What makes more noise from gradients?
     - Slice section thickness
     - FOV
     - RF Pulse bandwidth
    • ↧ in slice section thickness
    • ↧ in FOV
    • ↧ in RF Pulse bandwidth
  26. Noise can effect ...
    the Internal Auditory Canal
  27. Threshold
    TH - the point or level at which something begins or changes
  28. Safe TH noise dose (%?)
    66-80% does not cause any tympanic membrane damage
  29. TH noise dose is safe for tympanic membrane (%?)
    66-80%
  30. dB/dt
    Changint MF over time
  31. Changint MF over time is denoted by...
    dB/dt
  32. Noise Measurement
    dB
  33. Damage on analog wathces and credit catd strips can be at...
    10.0 Gauss
  34. Quench
       - first to do
    • demagnetization of the magnet 
    • explosion (not combustion - fire) 
    • dangerous event in MRI process
    • cause b/c Helium level to low and remain boil-off to the air
    •   - evacuate the room
  35. Dewar (capacity, pressure)
    • container to keep He
    • He should never be < 40%
    • Pressure not > 5 PSI (rate of circulation)
  36. MRI facility must be in:
    T - ?
    Humidity - ?
    • T = 65-70 F (room T)
    • Humidity = 55-70%
  37. Quench causes...
    • 1) Asphyxiation (chock)
    • 2) Frostbite
    • 3) Demagnetization
  38. MRI compatibles
    MRI safe testing is done @ 3T by Bio-Met
  39. MRI and Aneurysm clip
    • Conditional:
    •    - steel NO
    •    - titanium YES, but low field magnet 0.5T
  40. MRI and Cochlear implants
    • NO MRI - Soundbridge implant device
    • YES for - external hearing aids can be removed
  41. MRI and Pacemaker
    • NO MRI
    • YES for:
    •    - Gordon Wells Patch - temporary pacemaker (good for MRI)
  42. MRI contraindications
    • 1) Pacemaker
    •    - Gordon Wells Patch - temporary pacemaker (good for MRI)
    • 2) Aneurysm clip - conditional:
    •    - steel NO
    •    - titanium YES, but low field magnet 0.5T
    • 3) Cochlear implants
    •    - Soundbridge implant device
    •    - external hearing aids can be removed
    • 4) Whatever use bettery
  43. Pregnancy & MRI
    • No MRI w contrast
    •    - crossing placenta
    • Pregnant tech can work in MRI (NOT forbidden)
    •    - RF main concern, but it is in isocenter
    • 10 days rool:
    •    - save to do MRI within beginning of menstr to 10 days
    • Life-death situation:
    •    - can be done w consent from the doctor and radiologist
  44. Eyeliner taattoo
    • YES MRI - give Pt instruction
    • transient skin irritation or cutaneous swelling of the eyes and surrounding tissue
  45. Eyeliner makeup containing ferrous pigment
    • YES MRI - give Pt instruction
    • transient skin irritation or cutaneous swelling or the eyes and surrounding tissue
    • Fabio eyeliner - NO MRI
  46. Vascular stents
    • 99% compatible with MRI
    • Swan-Ganz Catheters - NO MRI b/c Eddy Current inductive heating may melt the catheter
  47. Boolet & MRI
    MRI can be done unless it is close to spinal cord
  48. Metall worker
    • Best way to deterct metal - x-ray
    • x-ray of the orbit before MRI
    • radiologist must to read
  49. MRI sedated Pt's
    • should be monitored (Pulse rate, O2 level & BP)
    • MRI compatable Pulse Oxymeter and Sphygmomanometer
  50. Claustrophobia
    • - health threat to the Pt
    • 1) Give clear, detailed and concise instruction (easiest, safest, most effective)
    • 2) Provide ear plugs
    • 3) Provide music
    • 4) Talk to the Pt b/w sequences. Can bring Pt out of the magnet.
    • 5) Allow family member in the scanning room
  51. Specific absorption rate limitation problems are more likely to be experienced with ... transmitter coil
    ... body ...
  52. Motion artifacts
    • - Ghosting
    • - phase encoding direction (mismapping the image)
  53. EKG Triggering
    • - MRI compatible electrodes are places on the Pt's chest
    • - synchronizint the TR and cardiac
  54. Synchronizing the TR and cardiac cycle
    • Pulse Triggering
    • EKG Triggering
  55. Respiratory gating
    • - controlled by Pt's breathing 
    • - echos are collected when Pt suspends respiration 
    • - for chest, abdomen and spine
    • - synchronizing TR w periodic motion
  56. Pulse Triggering
    • - transduser is placed on the toenail 
    • - transduser waits for a pulse wave before it begins to scan 
    • - TR is very limites 
    • - synchronizing the TR and cardiac
  57. Synchronizing TR w periodic motion
    Respiratory gating
  58. Motion artifacts can be reduces by...
    • ... Gating Techniques - echoes are only collected during the resting phase of the cardiac cycle
    • 1) Pulse Triggering
    •   - transduser is placed on the toenail
    •   - transduser waits for a pulse wave before it begins to scan
    •   - TR is very limites
    •   - synchronizing the TR and cardiac cycle
    • 2) EKG Triggering
    •   - MRI compatible electrodes are places on the Pt's chest
    •   - synchronizint the TR and cardiac cycle
    • 3) Respiratory gating
    •   - controlled by Pt's breathing
    •   - echos are collected when Pt suspends respiration
    •   - for chest, abdomen and spine
    •   - synchronizing TR w periodic motion
  59. The faster the blood flow, the ... the signal
    brighter
  60. The slower the blood flow,  the ... the signal
    lesser
  61. MRA common techniques:
    • 1) Time of flight
    • 2) Phase contrast (PC)
  62. Time of flight types:
    • 1) 2DTOF - 2D Time of flight
    •    - slower blood flow
    •    - peripheral vascular structures of the lower extremities
    • 2) 3DTOF - 3D Time of flight
    •    - faster moving blood
    •    - Circle of Willis, Carotid arteries, Aorta, Renal arteries...
  63. 2DTOF
    • - 2D Time of flight  
    • - slower blood flow  
    • - peripheral vascular structures of the lower extremities
  64. 3DTOF
    • - 3D Time of flight  
    • - faster moving blood  
    • - Circle of Willis, Carotid arteries, Aorta, Renal arteries
  65. MRA for Circle of Willis, Carotid arteries, Aorta, Renal arteries...
    • 3D Time of flight
    • faster moving blood
  66. MRA for peripheral vascular structures of the lower extremities
    • 2D Time of flight
    • slower blood flow
  67. MRA - PC
    • PC - Phase contrast
    • uses VENC - Velocity Encoding
    • signal obtained in all directions
    • for very slow blood flow
    • imaging venous phase
  68. VENC
    • - Velocity Encoding
    • - used in MRA - PC - Phase contrast
  69. MRA with Gadolinium Pentacetic Acid
    • - depends on the weight of the Pt
    • - 0.1 mmol/kg or 0.2 ml/kg
    • - no contraindication
    • Precautions:
    •    - asthma
    •    - pregnancy or breast feeding
    •         - no brest feeding for 2 days
    •    - any known alergic history
    • Used for:
    •    - dynamic scanning - liver and pituitary gland
    •    - to determine if BBB is broken of disrupted (enhancement)
    •    - any spinal surgery to see different b/w scar tissue and disc
    •    - arthographic studies (joint space)
    •    - to diagnose Osteomylatis
    • Lethal Dose: is in excess of 20cc/kg of body weigth

Card Set Information

Author:
 flashsmilenet
ID:
 292773
Filename:
 FSP Class-3 Safety
Updated:
 2015-07-24 19:44:59
Tags:
FSP Class Safety
Folders:
FSP Class
Description:
FSP Class-3 Safety
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