TG 284 MR Sim Flashcards
what does report include?
-equopment selection
-acceptance testing
-QA
-workflows
-guidance on motion and distortion management
-MR safety considerations
geometric uncertainties when we use MRI images to help with contouring on the CTSim
2 mm in brain and pelvis
5 mm in abdomen
geometric distortions are a bigger problem where?
for smaller targets
pros and cons of higher field strength
pros: higher SNR and resolution, higher aceleration factors to reduce scan times
cons: more expensive, more local heating, more susceptibility artifacts, distortion, chemical shift
considerations for MRI location given RT workflow
-should be near CTSim and treatment rooms
monthly QA?
report includes a consensu monthly QA program with tolerances
-includes laser alignment, table motion, center frequency, transmitter gain, geometric accuracy, spatial res., contrast, artifacts, check bore for foreign material
annual QA/commissioning?
-magnetic field drift test
-transmitter and gain calibration
-magnetic field homogeneity
-gradient non-linearity
-lasers and table alignment
-RF coil evaluation
-E2E
-eddy current compensation
daily QA
-CCTV/intercom
-check bore for metal objects
-laser alignment
-transmit gain
-central frequency
-basic coil SNR check
-spatial fidelity check
Is MRSim or CTSim done first?
both workflows are possible
effects of gradient non-linearities increase with what?
radial distance from the isocenter
MR-only treatment planning
Methods to generate synthetic CTs have largely included voxel122 and atlas-based approaches17, 123, 124 and more recently, deep learnin
unmet needs of MRSim
-3D gradient non-linearity correction
-Online Bo field mapping
-online geometric distortion correction
-4D MRI
-RT specific MRI sequences, RF coils, and affixed couches
-MR only treatment planning
