2016 AAPM Annual Meeting
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Session Title: Connecting Radiation Physics with Computational Biology
Question 1: Why do we not use full track structure (nanometer scale) Monte Carlo simulations for treatment plan evaluation?
Reference:Paganetti, H., Jiang, H., Parodi, K., Slopsema, R., & Engelsman, M. (2008). Clinical implementation of full Monte Carlo dose calculation in proton beam therapy. Physics in Medicine and Biology, 53(17), 4825–4853. http://doi.org/10.1088/0031-9155/53/17/023)?
Choice A:The computational time is too large to allow full track structure simulations and still too complex to influence clinical decisions.
Choice B:The effects are too small to matter when determining treatment outcome.
Choice C:Treatments are determined by physical doses to the target, and the delivered dose to the target is the same for macroscopic and microscopic Monte Carlo simulations.
Question 2: Nanometer scale Monte Carlo simulations are limited by physics (Heisenberg uncertainty) and our knowledge of cross sections and material compositions of sub-cellular components. Despite these limitations, for what applications are such simulations expected to be beneficial?
Reference:Thomson, R. M., & Kawrakow, I. (2011). On the Monte Carlo simulation of electron transport in the sub-1 keV energy range. Medical Physics, 38(8), 4531–4534. http://doi.org/10.1118/1.3608904
Choice A:Determining cell survival.
Choice B:Model developments for cell effects.
Choice C:Nothing.
Choice D:Predict cure rates.
Question 3: In clinical radiobiology, cells with a high a/ß ratio are most commonly associated with cells of what sort of tissue?
Reference: Radiobiology for the Radiologist 7th ed, Hall & Garcia, p393-407
Choice A:Rapidly-dividing and early responding tissues (e.g. skin, muscoa, most tumours).
Choice B:Slowly-dividing and late responding tissues (e.g. lung, Central Nervous System).
Choice C:No association with proliferation.
Question 4: In a typical repair-competent cell, approximately what fraction of DSBs lead to a lethal event?
Reference:Reference: Basic Clinical Radiobiology 4th ed, Joiner & van der Kogel, p13
Choice A:100%
Choice B:50%
Choice C:10%
Choice D:1%
Question 5: Which statement correctly describes the activity of DNA repair processes in a repair-competent cell throughout the cell cycle?
Reference:Pathways of DNA Double-Strand Break Repair During the Mammalian Cell Cycle, K Rothkamm et al, Mol Cell Biol 2003, 23(16):5706
Choice A:Which statement correctly describes the activity of DNA repair processes in a repair-competent cell throughout the cell cycle?
Choice B:Nonhomologous End Joining (NHEJ) is active only in the G1 and S phases, Homologous
Choice C:Recombination (HR) only in the G2 phase.
Choice D:HR is active in the G1 phase, NHEJ in the S and G2 phases.
Choice E:NHEJ is active throughout the cell cycle, HR in S and G2 phases.
Question 6: Which statement or statements best describe the formation of a cluster of DNA lesions by ionizing radiation?
Reference:Georgakilas AG, O'Neill P, Stewart RD. Induction and repair of clustered DNA lesions: what do we know so far? Radiat Res. 2013 Jul;180(1):100-9. doi: 10.1667/RR3041.1.
Choice A:Clusters of DNA lesions are formed by the action of individual particle tracks.
Choice B:Reactive chemical species produced outside the nuclear membrane are likely to diffusion and create DSB within the cell nucleus.
Choice C:Individual clusters of DNA lesions are formed by the direct and indirection action of two or more independent particle tracks.
Choice D:B and C.
Choice E:A and B.
Question 7: Reproductive cell death encompasses which of the following modes of cell death?
Reference:• Chu K, Teele N, Dewey MW, Albright N, Dewey WC. Computerized video time lapse study of cell cycle delay and arrest, mitotic catastrophe, apoptosis and clonogenic survival in irradiated 14-3-3sigma and CDKN1A (p21) knockout cell lines. Radiat Res. 2004 Sep;162(3):270-86. • Stewart RD, Yu VK, Georgakilas AG, Koumenis C, Park JH, Carlson DJ. Effects of radiation quality and oxygen on clustered DNA lesions and cell death. Radiat Res. 2011 Nov;176(5):587-602
Choice A:Apoptosis
Choice B:Permanent inhibition of mitosis.
Choice C:Mitotic catastrophe
Choice D:Delayed cell death days or weeks after irradiation.
Choice E:All of the above
Question 8: The RBE for reproductive cellular death is most closely related to which molecular endpoint?
Reference:• Goodhead DT. Initial events in the cellular effects of ionizing radiations: clustered damage in DNA. Int J Radiat Biol. 1994 Jan;65(1):7-17. • Hlatky L, Sachs RK, Vazquez M, Cornforth MN. Radiation-induced chromosome aberrations: insights gained from biophysical modeling. Bioessays. 2002 Aug;24(8):714-23. • Stewart RD, Yu VK, Georgakilas AG, Koumenis C, Park JH, Carlson DJ. Effects of radiation quality and oxygen on clustered DNA lesions and cell death. Radiat Res. 2011 Nov;176(5):587-602.
Choice A:SSB induction.
Choice B:DSB induction.
Choice C:Base damage, including complex clusters of base damage.
Choice D:Chromosome aberrations.
Choice E:None of the above.
Question 9: Particle RBE for the endpoint of organ at risk (OAR) tolerance doses....
Reference:• Asbell SO, Grimm J, Xue J, Chew MS, LaCouture TA. Introduction and Clinical Overview of the DVH Risk Map. Semin Radiat Oncol. 2016 Apr;26(2):89-96. doi: 10.1016/j.semradonc.2015.11.005. Epub 2015 Dec 4. • Hall EJ, Giaccia AJ, Radiobiology for the Radiologist, 6th Edition, 2006 Lippincott Williams & Wilkins, (2006)
Choice A:Depend on the fractionation schedule selected for the MV x-ray (reference radiation) fractionation schedule.
Choice B:Increase with decreasing tissue (α/β).
Choice C:Decrease with increasing tissue (α/β).
Choice D:A and B.
Choice E:A and C.
Question 10: Are track structure simulations truly needed for radiobiology at the cellular and tissue levels?
Reference:Are track structure simulations truly needed for radiobiology at the cellular and tissue levels? Robert D. Stewart, Ph.D.
Choice A:Yes
Choice B:No
Choice C:Maybe
Choice D:All of the Above
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