2017 AAPM Annual Meeting
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Session Title: Microscopic Monte Carlo Simulations for Radiobiology Modeling: Advances and Challenges
Question 1: The major differences between macroscopic and sub-cellular MC simulations include all of the following EXCEPT:
Reference:Incerti, S, M Douglass, S Penfold, S Guatelli, and E Bezak. 2016. “Review of Geant4-DNA Applications for Micro and Nanoscale Simulations.” Physica Medica, September. doi:10.1016/j.ejmp.2016.09.007.
Choice A:Grouped particle interactions vs. explicit simulation of all interactions (track structure).
Choice B:Highly increased simulation time.
Choice C:Explicitly models biological repair processes.
Choice D:Can include modeling of chemical processes (reactive oxygen species).
Question 2: The goal of microscopic MC efforts is to:
Reference:Friedland, Werner, Michael Dingfelder, Pavel Kundrát, and Peter Jacob. 2011. “Track Structures, DNA Targets and Radiation Effects in the Biophysical Monte Carlo Simulation Code PARTRAC.” Mutation Research 711 (1-2): 28–40. doi:10.1016/j.mrfmmm.2011.01.003.
Choice A:Avoid uncertainties at voxel boundaries.
Choice B:Understand biological processes from the bottom up.
Choice C:Replace treatment planning systems to optimize cell survival.
Choice D:Calculate the survival probability for each cell in a tumor volume.
Question 3: Track structure simulations will soon replace macroscopic MC simulations for patient dose calculations.
Reference:Bernal, M A, M C Bordage, J M C Brown, M Davidkova, E Delage, Z El Bitar, S A Enger, et al. 2015. “Track Structure Modeling in Liquid Water: a Review of the Geant4-DNA Very Low Energy Extension of the Geant4 Monte Carlo Simulation Toolkit.” Physica Medica : PM : an International Journal Devoted to the Applications of Physics to Medicine and Biology : Official Journal of the Italian Association of Biomedical Physics (AIFB) 31 (8): 861–74. doi:10.1016/j.ejmp.2015.10.087.
Choice A:True.
Choice B:False.
Question 4: In general, which of the following is not needed for simulating the nonhomogeneous chemistry (e.g., water radiolysis) in Monte-Carlo codes?
Reference:Friedland et al., Mutat. Res. 711, 28-40 (2011).
Choice A:Reaction rate constants.
Choice B:Diffusion coefficients of particles.
Choice C:Ionization cross sections.
Choice D:Concentration of molecules in the medium.
Question 5: Which of the following is not a typical interaction of ions with condensed matter?
Reference:Schardt D et al., Rev. Mod. Phys. 82, 383-425 (2010).
Choice A:Compton effect.
Choice B:Excitation of electrons.
Choice C:Ionization of electrons.
Choice D:Charge transfer.
Question 6: Which phenomenon does not happen in the first microsecond of the radiation action?
Reference:Nikhoo H, Iran. J. Radiat. Res. 1, 1-16 (2003).
Choice A:Electron thermalization.
Choice B:Enzymatic reactions.
Choice C:Reactions of free radical species.
Choice D:Ionization of molecules.
Question 7: A possible extra-nuclear DNA target is:
Reference:Zhang B, Davidson M M, Hei T K. 2014. “Mitochondria regulate DNA damage and genomic instability induced by high LET radiation” Life Sciences in Space Research 1, 80-88. doi: 10.1016/j.lssr.2014.02.006.
Choice A:Mitochondrial DNA.
Choice B:Chromosome.
Choice C:Vacuole.
Choice D:All of the above.
Question 8: Damage to DNA can be calculated with track structure simulations with either a clustering algorithm or by scoring energy depositions within a geometric 3D model.
Reference:Incerti S, Douglass M, Penfold S, Guatelli S, Bezak E. 2016. “Review of Geant4-DNA applications for micro and nanoscale simulations” Physica Medica 32 (10), 1187–1200. doi: 10.1016/j.ejmp.2016.09.007.
Choice A:True.
Choice B:False.
Question 9: Which of the following belongs to chemical stage of water radiolysis?
Reference:Kalantzis G, Emfietzoglou D and Hadjidoukas P 2012 A unified spatio-temporal parallelization framework for accelerated Monte Carlo radiobiological modeling of electron tracks and subsequent radiation chemistry Computer Physics Communications 183 1683-95.
Choice A:Transport of radiation particles and energy deposition.
Choice B:Generation of ionized and excited water molecules and subexcitation electrons.
Choice C:Dissociation of ionized and excited water molecules, and solvation of subexcitation electrons.
Choice D:Diffusion of the radiolytic molecules and chemical reactions between them.
Question 10: Why is the simulation of the chemical stage of water radiolysis more time consuming than the other two stages?
Reference:Tian Z, Jiang SB, Jia X. “Accelerated Monte Carlo Simulation on the Chemical Stage in Water Radiolysis using GPU”, PMB (in print), 2017.
Choice A:The chemical stage involves several orders of magnitude in terms of time, and requires many time steps to simulate this dynamic process.
Choice B:An incident ionizing particle can generate a large number of radiolytic molecules in water, whose activities need to be simulated in this stage.
Choice C:The mutual and competitive chemical reactions between the radiolytic molecules cause a highly correlated many-body simulation problem.
Choice D:All of the above.
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