| Question 1: What is the advantage of a clinic running their own MR scanner? |
| Reference: | Karlsson et al, Dedicated Magnetic Resonance Imaging in the Radiotherapy Clinic, Int. J. Radiation Oncology Biol. Phys., Vol. 74, No. 2, pp. 644–651, 2009.None, it is always better to use an MR housed in a radiology department |
| Choice A: | Reduced chance of patient-induced distortions |
| Choice B: | The direct transfer of knowledge from CT simulation to MR simulation, eliminating the requirement for new training of simulation therapists |
| Choice C: | The ability to customize the scanner for radiation therapy specific needs such as a flat couch and non-invasive coils |
| Choice D: | None, it is always better to use an MR housed in a radiology department |
| Question 2: The registration errors associated with fusing MR to CT images: |
| Reference: | Reference: Karlsson et al, Dedicated Magnetic Resonance Imaging in the Radiotherapy Clinic, Int. J. Radiation Oncology Biol. Phys., Vol. 74, No. 2, pp. 644–651, 2009. |
| Choice A: | Are eliminated when the department hosts its own MR scanner |
| Choice B: | Are eliminated with MR-only simulations |
| Choice C: | Are never eliminated since CT is always used in radiation therapy treatment planning |
| Choice D: | Are eliminated by using a 1.5T MR scanner. |
| Question 3: Radiation Therapy with integrated MR and linear accelerator systems |
| Reference: | Reference: Practical Safety Considerations for Integration of Magnetic Resonance Imaging in Radiation Therapy, Practical Radiation Oncology® (2020) 10, 443-453. |
| Choice A: | Cannot be used for high accuracy treatments because they do not include on-board CT scanners |
| Choice B: | Compromises image quality in favor of more rapid image acquisition (relative to on-board CT systems). |
| Choice C: | Does not need to concern itself with the magnetic field affecting the radiation dose because the radiation dose is delivered by x rays |
| Choice D: | Requires that a clinic integrates and uses MR safety training and awareness |
| Question 4: The integrated MR systems in MRgRT |
| Reference: | Raaijmakers et al, Integrating a MRI scanner with a 6 MV radiotherapy accelerator: dose increase at tissue-air interfaces in a lateral magnetic field due to returning electrons, PHYSICS IN MEDICINE AND BIOLOGY, Volume: 50 Issue: 7 Pages: 1363-1376 |
| Choice A: | Provide radiation doses that are perturbed more by patient density heterogeneities than doses delivered using conventional radiation therapy machines |
| Choice B: | Cannot be operated at the same time as the radiation delivery systems due to the Lorenz force on the linear accelerator |
| Choice C: | Do not need magnetic field shielding to isolate the linear accelerator from the main magnetic field |
| Choice D: | Operate on different physical principles than do conventional MR scanners |
| Question 5: The Bloch equation dictates |
| Reference: | Reference: F. Bloch, "Nuclear Induction", Physical Review 70, 4604–73 (1946) |
| Choice A: | the motion of the bulk magnetization in the B0 magnetic field |
| Choice B: | how MR images are reconstructed from the k-space data |
| Choice C: | how the concomitant field is generated by the gradient fields |
| Choice D: | the amount of eddy currents generated when running an MRI pulse sequence |
| Question 6: A gradient field in the X direction is NOT |
| Reference: | Magnetic Resonance Imaging: Physical Principles and Sequence Design, by Robert Brown, PhD et al., Wiley Blackwell, ISBN-13: 978-0471720850, ISBN-10: 0471720852 |
| Choice A: | a spatially varying magnetic field |
| Choice B: | a magnetic field that is aligned along the X direction |
| Choice C: | a necessary step in spatial encoding in the X direction in MRI |
| Choice D: | a source of the noise generated by the MRI system when running a pulse sequence |
| Question 7: emical shift could cause |
| Reference: | Handbook of MRI pulse sequence. Bernstein et al., Elsevier Academic Press, ISBN-13: 978-0-12-092861-3 |
| Choice A: | distortion in the reconstructed MR images |
| Choice B: | spatial mis-encoding in MRI |
| Choice C: | signal cancellation |
| Choice D: | all of the above |
| Question 8: Magnetic field homogeneity over a diameter of spherical volume |
| Reference: | Gach HM, et al, “B0 field homogeneity recommendations, specifications, and measurement units for MRI in radiation therapy”, Med Phys. 2020 Sep;47(9):4101-4114. doi: 10.1002/mp.14306. Epub 2020 Jul 19 |
| Choice A: | Decreases as distance from isocenter when measured as root-mean square variance |
| Choice B: | Decreases as distance from isocenter when measured as peak-to-peak change |
| Choice C: | Increases as distance from isocenter |
| Choice D: | Increases with smaller bore size |
| Question 9: The ‘gradient’ in the x-direction (Gx) is a representation of: |
| Reference: | “The Essential Physics of Medical Imaging”; Bushberg JT, et al, 3rd Edition, Lippincott Williams & Wilkins, 2012 |
| Choice A: | Changes in the x-component of the magnetic field in the x-direction |
| Choice B: | Changes in the z-component of the magnetic field in the x-direction |
| Choice C: | Changes in the absolute value of the magnetic field in the x-direction |
| Choice D: | Uncertainty of the magnetic field in the x-direction |
| Question 10: The spatial heterogeneity in MR phase-array receive coils can be used to encode spatial information. The general term for this form of image acceleration is called: |
| Reference: | “RF coils: A practical guide for nonphysicists”; Bruber B, et al, J Magn Reson Imaging
. 2018 Jun 13;48(3):590-604. doi: 10.1002/jmri.26187. |
| Choice A: | Parallel imaging |
| Choice B: | Compressed sensing |
| Choice C: | Parallel transmit |
| Choice D: | Parallel transmit |
