MRSO - RADIO FREQUENCY - MODULE 4 Questions & Correct Revised Verified Answers
1 view 0 purchase
Course
MRSO
Institution
MRSO
When determining RF energy, strength of magnetic field is measured in - Answer mT
Main biological effect of exposing tissue to electromagnetic radiation in that frequency
range - Answer tissue heating
Cause of tissue heating - Answer Magnetic induction results in eddy currents of
conductive tis...
MRSO - RADIO FREQUENCY - MODULE 4
Questions & Correct Revised Verified Answers
When determining RF energy, strength of magnetic field is measured in - Answer mT
Main biological effect of exposing tissue to electromagnetic radiation in that frequency
range - Answer tissue heating
Cause of tissue heating - Answer Magnetic induction results in eddy currents of
conductive tissue
Tissue heating is mostly ______________ with very little _______________ - Answer
peripheral , deep body heating
How patient dissipates RF power - Answer cooling.
If the input is greater than the output, heating occurs.
SAR (specific absorption rate) - Answer RF power absorbed per unit mass of tissue
SAR is SPECIFIC to: - Answer body part and tissue
SAR represents - Answer ABSORPTION of RF into the body/tissues
SAR is the - Answer RATE of RF exposure and absorption
SAR is measured in - Answer watts/kg
, SAR is proportional to: - Answer -the power of 2 for system's resonant frequency (factor
of 4)
-the power of 2 for B1 amplitude of RF field (doubling flip angle with increase SAR by
factor of 4)
-the power of 5 for the pt's circumference
-patient's average conductivity
Is muscle or fat more conductive? - Answer muscle
SAR is not measured, it is: - Answer estimated via algorithms that differ with MR
manufacturer
There is no standard for SAR estimations - Answer each vendor uses different algorithm
Estimations of SAR are based on: - Answer -field strength
-RF frequency / coil
-scan parameters: type, # RF pulses, TR, # of slices per TR
-pt characteristics: weight, height, body part
-assumed tissue conductivity
It is widely accepted that most if not all vendors are very
___________________________ in their SAR estimates - Answer conservative
SAR is believed to serve as a - Answer crude measure of heating potential
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Examsplug. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
