Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental assessment of clinical MRI-induced global SAR distributions
  in head phantoms   Objective: Accurate estimation of SAR is critical to safeguarding vulnerable
patients who require an MRI procedure. The increased static field strength and
RF duty cycle capabilities in modern MRI scanners mean that systems can easily
exceed safe SAR levels for patients. Advisory protocols routinely used to
establish quality assurance protocols are not required to advise on the testing
of MRI SAR levels and is not routinely measured in annual medical physics
quality assurance checks. This study aims to develop a head phantom and
protocol that can independently verify global SAR for MRI clinical scanners.
  Methods: A four-channel birdcage head coil was used for RF transmission and
signal reception. Proton resonance shift thermometry was used to estimate SAR.
The SAR estimates were verified by comparing results against two other
independent measures, then applied to a further four scanners at field
strengths of 1.5 T and 3 T.
  Results: Scanner output SAR values ranged from 0.42 to 1.52 W/kg. Percentage
SAR differences between independently estimated values and those calculated by
the scanners differed by 0-2.3%.
  Conclusion: We have developed a quality assurance protocol to independently
verify the SAR output of MRI scanners.

5
The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph