| Question 1: The following are accepted techniques to mitigate the risk of brain stem necrosis in proton therapy, EXCEPT |
| Reference: | Vogel J, Grewal A, O'Reilly S, et al. Risk of brainstem necrosis in pediatric patients with central nervous system malignancies after pencil beam scanning proton therapy. Acta Oncol. 2019;58(12):1752-1756. doi:10.1080/0284186X.2019.1659996 |
| Choice A: | Avoidance of proton beams stopping in the same location of the brain stem |
| Choice B: | Heavily weighted beam spots next to the brain stem |
| Choice C: | Overshooting pencil beams into the center of the brain stem to avoid high LET at the brain stem surface |
| Question 2: Which of the following was a significant finding in a recent treatment planning study that investigated the impact of range uncertainty on the distributions of linear energy transfer in CTV and OARs |
| Reference: | Hahn C, Eulitz J, Peters N, et al. Impact of range uncertainty on clinical distributions of linear energy transfer and biological effectiveness in proton therapy. Med Phys. 2020;47(12):6151-6162. doi:10.1002/mp.14560 |
| Choice A: | LETd hotspots and the impact of range deviations were most prominent in OARs |
| Choice B: | LETd distributions in the CTV were rather inhomogeneous and sensitive to the presence of range uncertainties |
| Choice C: | The optimization technique (single- vs multi-field) had a large impact on the LETd distributions |
| Question 3: Relative biological effectiveness (RBE) of protons increases |
| Reference: | Wouters BG, Lam GK, Oelfke U, et al. Measurements of relative biological effectiveness of the 70 MeV proton beam at Triumf using Chinese hamster v79 cells and the high-precision cell sorter assay. Radiat Res 1996;146:159-70. http://www.ncbi.nlm.nih.gov/pubmed/8693066 |
| Choice A: | As proton dose increases |
| Choice B: | As linear energy transfer (LET) increases |
| Choice C: | As proton energy at the point of interest increases |
| Question 4: IMPT dose distributions, compared to IMRT dose distributions, are |
| Reference: | Mohan R, Das IJ, Ling CC. Empowering intensity modulated proton therapy through physics and technology: An overview. Int J Radiat Oncol Biol Phys 2017;99:304-316. https://www.ncbi.nlm.nih.gov/pubmed/28871980 |
| Choice A: | Less sensitive to anatomy changes over the course of radiotherapy |
| Choice B: | More sensitive to tumor motion only when it exceeds 10 mm |
| Choice C: | More sensitive to inter-fractional changes and intra-fractional motion of any anatomy in the path of protons |
| Question 5: Which of the following in-vivo range verification techniques can help mitigating range uncertainties during proton therapy delivery? |
| Reference: | K. Parodi, Latest developments in in-vivo imaging for proton therapy, Br J Radiol 2020 93(1107):20190787 |
| Choice A: | X-ray fluoroscopy |
| Choice B: | Proton computed tomography |
| Choice C: | Prompt gamma imaging |
| Question 6: How can the reduction of proton range uncertainties improve treatment plans? |
| Reference: | Sebastian Tattenberg, Thomas M Madden, Bram L Gorissen, Thomas Bortfeld, Katia Parodi, Joost Verburg, Proton range uncertainty reduction benefits for skull base tumors in terms of normal tissue complication probability (NTCP) and healthy tissue doses, Med Phys 2021 ;48(9) 5356-5366 |
| Choice A: | The reduction results in a decreased amount of stray radiation from secondary neutrons which in turn reduces the risk of secondary malignancies |
| Choice B: | The reduction can result in treatment plans of reduced radiation exposure to normal tissue |
| Choice C: | The reduction can only result in improved tumour coverage and enhanced robustness, but not in reduced toxicities |
| Question 7: Which of the following describes the main purpose of using seed spot analysis |
| Reference: | Yang, Y; Patel, SH; Bridhikitti, J; Wong, WW; Halyard, MY; McGee, LA; Rwigema, JCM; Schild, SE; Vora, SA; Liu, TM; Bues, M; Fatyga, M; Foote, RL; Liu, W. Seed spots analysis to characterize dose and linear energy transfer effect in adverse event initialization of pencil beam scanning proton therapy, under review in Med. Phys. 2022. |
| Choice A: | To remove potential biological effect and find independent voxels that are directly induced from dosimetric effect |
| Choice B: | To include LET as an independent variable for analysis |
| Choice C: | To study normal tissue complication probability that are related to the high LET |
| Question 8: In voxel-based analysis, each voxel within damaged tissue is treated as an independent data point to establish the relationship of dosimetric factors (dose and LET) with the patient outcome (a damaged voxel or not). However, in a situation that part of the damage is caused by consequential biological effects after dose/LET-induced initiation, which of the following statement is incorrect? |
| Reference: | Yang, Y; Patel, SH; Bridhikitti, J; Wong, WW; Halyard, MY; McGee, LA; Rwigema, JCM; Schild, SE; Vora, SA; Liu, TM; Bues, M; Fatyga, M; Foote, RL; Liu, W. Seed spots analysis to characterize dose and linear energy transfer effect in adverse event initialization of pencil beam scanning proton therapy, under review in Med. Phys. 2022. |
| Choice A: | One can still associate dosimetric factors of all voxels in the damaged lesion with the corresponding voxel response |
| Choice B: | Voxels within the damaged lesion are still independent from each other |
| Choice C: | Both statements above are incorrect |
| Question 9: Phenomenological proton RBE models are generally based on: |
| Reference: | Rørvik E, Fjæra LF, Dahle TJ, Dale JE, Engeseth GM, Stokkevåg CH, et al., Exploration and application of phenomenological RBE models for proton therapy. Phys. Med. Biol. 2018; 63: 185013. |
| Choice A: | Clinical data |
| Choice B: | The linear-quadratic model using empirical data of clonogenic cell survival for fitting |
| Choice C: | Monte Carlo simulation data |
| Choice D: | Experimental data on DNA strand breaks |
| Question 10: Monte Carlo track structure simulations: |
| Reference: | Friedland W, Dingfelder M, Kundrát P, Jacob P, Track structures, DNA targets and radiation effects in the biophysical Monte Carlo simulation code PARTRAC, Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 2011, 711, 28-40. |
| Choice A: | Models the clustering of energy depositions along the particle track, down
to very low energies |
| Choice B: | Includes the physiochemical stage producing hydrolysis chemical species |
| Choice C: | Predicts DNA strand damage |
| Choice D: | All of the above |
