2016 AAPM Annual Meeting
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Session Title: Motion Management for Pencil Beam Scanning Proton Therapy
Question 1: Why is scanning proton beam more sensitive to motion than passive scatter proton beams?
Reference:Reference: Principles and Practice of Proton Beam Therapy. Ed(s) Indra J. Das and Harald Paganetti. Medical Physics Publishing, 2015, chapter 25, motion management.
Choice A:The motion of the beam could interfere with the motion of target and result in the distortion of the dose distribution.
Choice B:Due to the finite range of the protons, the beam could stop in the target and compromise target coverage.
Choice C:The scanning beam plans are usually more conformal than the passive scatter plans.
Choice D:Scanning beam proton beams are no more sensitive to motion than passive scatter proton beams.
Question 2: Which technique will NOT reduce/mitigate dose uncertainties due to respiratory motion for scanning proton beams (i.e., improve dose homogeneity to the target)?
Reference:Reference: Principles and Practice of Proton Beam Therapy. Ed(s) Indra J. Das and Harald Paganetti. Medical Physics Publishing, 2015, chapter 25, motion management.
Choice A:Increasing PTV margin.
Choice B:Repainting.
Choice C:Gating.
Choice D:Using breath-hold technique.
Question 3: Which component of patient motion contributes most to the interplay effect?
Reference:Reference: Principles and Practice of Proton Beam Therapy, Das and Paganetti, editors, Chapter 9, Field Shaping: Scanning Beam (Medical Physics Publishing, Madison, 2015)
Choice A:The component parallel to the incident proton beam.
Choice B:The component perpendicular to the incident proton beam.
Choice C:Both (A) and (B).
Choice D:None of the above.
Question 4: The change in water equivalent thickness (WET) along the beam path between inhale and exhale can be used to select:
Reference:Principles and Practice of Proton Beam Therapy, Das and Paganetti, editors, Chapter 9, Field Shaping: Scanning Beam (Medical Physics Publishing, Madison, 2015)
Choice A:The scanning direction of PBS.
Choice B:The method for repainting.
Choice C:The gantry angles.
Choice D:All above.
Question 5: Which of the following statements is not a reason why pencil beam scanning treatments for liver tumors is less controversial than that of lung tumors?
Reference:Knopf, A. C., Boye, D., Lomax, A., & Mori, S. (2013). Adequate margin definition for scanned particle therapy in the incidence of intrafractional motion. Physics in Medicine and Biology, 58(17), 6079.
Choice A:A range-adapted ITV is closer to a traditional ITV because adjacent regions are not low density.
Choice B:The interplay effect is negligible without rescanning or any other mitigation strategy.
Question 6: Which of the following is not a reason why abdominal compression is used in radiation therapy treatments of liver and lung tumors?
Reference:: Heinzerling, J. H., Anderson, J. F., Papiez, L., Boike, T., Chien, S., Zhang, G., ... & Timmerman, R. (2008). Four-dimensional computed tomography scan analysis of tumor and organ motion at varying levels of abdominal compression during stereotactic treatment of lung and liver. International Journal of Radiation Oncology* Biology* Physics, 70(5), 1571-1578.
Choice A:It reduces intrafraction motion.
Choice B:It reduces interfraction motion.
Choice C:It can decrease the magnitude of motion according to patient tolerance.
Choice D:It reduces organ motion especially those related to diaphragm.
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