| Question 1: 1. Commissioning of an MR Linac should: |
| Reference: | Jackson, E. et al. “Acceptance Testing and Quality Assurance Procedures for Magnetic Resonance Imaging Facilities : Report of MR Subcommittee Task Group 1,” 2010, AAPM Report 100, https://www.aapm.org/pubs/reports/RPT_100.pdf
Klein, E. et al. “Task Group 142 report: Quality assurance of medical accelerators,” 2009, Medical Physics, 36 (9), 4197-4212
Huq, S. et al. “The report of Task Group 100 of the AAPM: Application of risk analysis methods to radiation therapy quality management,” 2016, Medical Physics, 43 (7), 4209-4262 |
| Choice A: | Follow the recommendations of the task group report on MR-Linac Commissioning published in 2019 |
| Choice B: | Be performed according to the guidelines in AAPM TG-142, the same as would be done for a conventional linac |
| Choice C: | Include all elements from both AAPM TG-142 (for the linear acceleratory subsystem) and all elements from the AAPM MR TG-1 (for the MRI System) |
| Choice D: | Include appropriate elements from AAPM commissioning task groups (TG-142 and MR TG-1) and ACR guidance, as well as additional tests based on TG-100 methodologies that reflect how the machine will be used clinically |
| Question 2: The magnetic field in an MR-Linac poses challenges for commissioning because: |
| Reference: | Meijsing, I., et al. "Dosimetry for the MRI accelerator: the impact of a magnetic field on the response of a Farmer NE2571 ionization chamber." Physics in Medicine & Biology 54.10 (2009): 2993 |
| Choice A: | All commissioning measurements of the linac dosimetry system should be performed with the MRI magnet powered off |
| Choice B: | The magnetic field can impact detector performance, and limits the devices and equipment that can be used for measurements |
| Choice C: | The electron return effect causes ion chambers to be unusable |
| Choice D: | The light field from the linac is the only reliable indicator of field size |
| Question 3: Which of the following is the largest system-induced source of geometric distortion in MR simulation? |
| Reference: | Wang et al., Geometric distortion in clinical MRI systems Part I: evaluation using a 3D phantom. Magnetic Resonance Imaging 22(9) 2004:1211-1221 |
| Choice A: | B0 field inhomogeneity |
| Choice B: | Chemical Shift |
| Choice C: | Gradient non-linearity |
| Choice D: | Susceptibility artifacts |
| Question 4: Which of the following is not a major difference between MR simulation in RT and diagnostic MRI applications |
| Reference: | Paulson et al.,Comprehensive MRI simulation methodology for external beam radiation therapy planning. Medical Physics 42(1) 2015:28-39 |
| Choice A: | Immobilization devices |
| Choice B: | RF receiving coil configurations |
| Choice C: | Field of view |
| Choice D: | Magnet Field strength |
| Choice E: | Readout bandwidth |
| Choice F: | Flat tabletop |
| Question 5: Which of the following is true? In comparison to a prostate volume drawn on MR, the prostate delineated on TRUS and CT are: |
| Reference: | Smith et al, IJROBP 64 (2007) 1238-1247 |
| Choice A: | Larger by 16% for TRUS and larger by 16% for CT |
| Choice B: | Smaller by 10% for TRUS and larger by 16% for CT |
| Choice C: | Larger by 16% for TRUS and smaller by 10% for CT |
| Choice D: | Smaller by 10% for TRUS and smaller by 10% for CT |
| Question 6: Which of the following are commissioning tests that should be conducted when commissioning an applicator for MR based brachytherapy? |
| Reference: | Hellebust et al. Radiotherapy and Oncology 96.2 (2010): 153-160. |
| Choice A: | Identification of the Index position of the most distal dwell position |
| Choice B: | Measurement of the distance of the most distal dwell to outer surface of applicator |
| Choice C: | Spot checks of source path for curved applicators |
| Choice D: | Evaluation of the Imaging artefacts introduced by metallic applicators |
| Choice E: | All of the above |
