Question 1: For a patient treated on an MR-Linac or for repeated MRI simulation scans, the patient only needs to be screened for MRI safety once. Then they should be OK through all of the RT treatment fractions. |
Reference: | van der Heide UA, Frantzen-Steneker M, Astreinidou E, Nowee ME, van Houdt PJ, MRI basics for radiation oncologists, Clin Transl Radiat Oncol. 2019 Apr 13;18:74-79 |
Choice A: | Yes |
Choice B: | No |
Question 2: Who should be trained about MRI safety in a radiation therapy department? |
Reference: | van der Heide UA, Frantzen-Steneker M, Astreinidou E, Nowee ME, van Houdt PJ, MRI basics for radiation oncologists, Clin Transl Radiat Oncol. 2019 Apr 13;18:74-79 |
Choice A: | Radiation physicists |
Choice B: | Radiation oncologists, residents, physician assistants |
Choice C: | Dosimetrist |
Choice D: | RTTs |
Choice E: | All of above |
Choice F: | only physicists who work around MRI should be trained |
Question 3: The following factors need to be considered when performing reference dosimetry in an MR-Linac: |
Reference: | 1/ Malkov V and Rogers DWO. Monte Carlo study of ionization chamber magnetic field correction factors as a function of angle and beam quality. Med Phys 45(2), 908-925, 2018
2/ Iakovenko V et al. Experimental measurement of ionization chamber angular response and associated magnetic field correction factors in MR-Linac. Med Phys 47(4), 1940 – 1948, 2020 |
Choice A: | A correction factor in the TG-51 formalism that accounts for the chamber being irradiated in the presence of a magnetic field. |
Choice B: | The orientation of the chamber with respect to the magnetic field. |
Choice C: | The electron return effect where the beam exits the water phantom. |
Choice D: | A and B only |
Choice E: | A, B and C |
Question 4: Which of the following statements is false with regard to an MR-Linac ? |
Reference: | 1/ Woodings SJ, Bluemink JJ, de Vries JHW, et al. Beam characterisation of the 1.5T MRI-linac. Phys Med Biol. 63(8), 085015, 2018.
2/ Perik et al. The impact of a 1.5 T MRI linac fringe field on neighbouring linear accelerators. Physics and Imaging in Radiation Oncology 4, 12-16, 2017.
3/ O’Brien et al. Monte Carlo study of the chamber-phantom air gap effect in a magnetic field. Med Phys 44(7), 3830-3838, 2017.
4/ Perik et al. Master’s thesis, University of Heidelberg, Germany, 2017. |
Choice A: | The profiles are skewed in the direction parallel to the magnetic field. |
Choice B: | Small air gaps, of the order of a fraction of a millimeter, can have noticeable effects when irradiating a farmer chamber in a plastic phantom. |
Choice C: | Microdiamond detectors can be used when scanning profiles and PDD’s in an MR-Linac. |
Choice D: | Gafchromic film is prone to air gaps effecting its response. |
Choice E: | It is advisable to verify that there are no beam steering effects for linacs in close proximity to an MR-Linac. |
Question 5: Pancreatic cancer is one of the most common sites for which MRI-guided ART is indicated. All of the following are reasons for this, EXCEPT: |
Reference: | Boldrini, L., Cusumano, D., Cellini, F., Azario, L., Mattiucci, GC., and Valentini, V, “Online Adaptive Magnetic Resonance Guided Radiotherapy for Pancreatic Cancer: State of the Art, Pearls and Pitfalls, Radiat Oncol, 14 (1), 2019 Apr 29. |
Choice A: | Target dose is limited by the toxicity of highly radio-sensitive abdominal organs at risk. |
Choice B: | Treatment delivery is complicated by the significant inter-fractional anatomic changes due to variable organ filling. |
Choice C: | High soft tissue contrast of MRI aids in accurate daily volumetric contouring. |
Choice D: | There can be significant pancreatic tumor regression over the course of SBRT delivery. |
Question 6: What are 4 essential elements of an online ART workflow prior to treatment delivery? |
Reference: | Lim-Reinders, S,. Keller, B., Al-Ward, S., Sahgal, A and Kim A., “Online Adaptive Radiation Therapy” IJROBP, 99(4), 2017 Nov 17. |
Choice A: | Pre-treatment CT for each fraction to acquire density map, DIR, accelerated re-planning and patient specific QA checks. |
Choice B: | Daily in-room imaging, DIR, accelerated re-planning and patient specific QA checks. |
Choice C: | Daily in-room imaging, Monte Carlo optimization, DIR and pre-treatment QA measurements. |
Choice D: | Rigid registration/couch shifts, Monte Carlo optimization, auto-segmentation followed by dosimetrist review and pre-treatment DQA measurements. |