2021 AAPM Virtual 63rd Annual Meeting
Back to session list

Session Title: Novel Imaging Technologies for Motion Management in Radiotherapy
Question 1: Which of following is true for respiratory-correlated 4D-MRI?
Reference:Respiratory-Correlated (RC) vs. Time-Resolved (TR) Four-Dimensional Magnetic Resonance Imaging (4DMRI) for Radiotherapy of Thoracic and Abdominal Cancer, Guang Li, Yilin Liu , Xingyu Nie , Front Oncol. 2019 Oct 11; 9:1024. PMID: 31681573
Choice A:The fourth dimension is time
Choice B:The fourth dimension is phase/amplitude bin
Choice C:Is superior to 4D-CT in tumor contrast when imaging abdominal tumor motion
Choice D:b & c
Question 2: What acquisition methods are used in 4D-MRI?
Reference:Nuts and bolts of 4D-MRI for radiotherapy, B Stemkens, E S Paulson, R H N Tijssen, Phys Med Biol. 2018 Oct 23;63(21):21TR01. PMID: 30272573
Choice A:2D/3D Cartesian
Choice B:3D stack-of-stars
Choice C:3D Radial
Choice D:all of above
Question 3: 4D-CBCT typically requires a much longer scanning time than 3D-CBCT because
Reference:1. Li, Tianfang, and Lei Xing. "Optimizing 4D cone-beam CT acquisition protocol for external beam radiotherapy." International Journal of Radiation Oncology* Biology* Physics 67.4 (2007): 1211-1219. 2. Zhang, Y., Yin, F. F., Pan, T., Vergalasova, I., & Ren, L. (2015). Preliminary clinical evaluation of a 4D-CBCT estimation technique using prior information and limited-angle projections. Radiotherapy and Oncology, 115(1), 22-29.
Choice A:4D-CBCT needs to acquire adequate projections for each phase bin
Choice B:4D-CBCT needs longer scanning time to average out the motion effects
Choice C:4D-CBCT needs more projections to reduce the scatter artifacts
Choice D:4D-CBCT uses longer scanning time to reduce the imaging dose
Question 4: What’s the advantage of motion compensated 4D-CBCT reconstruction compared to simple FDK back-projection reconstruction?
Reference:Shieh, Chun‐Chien, et al. "SPARE: Sparse‐view reconstruction challenge for 4D cone‐beam CT from a 1‐min scan." Medical physics 46.9 (2019): 3799-3811.
Choice A:Faster speed
Choice B:Computationally less expensive
Choice C:Better scatter correction
Choice D:Less streak artifacts caused by under sampling
Question 5: DDG PET/CT vs. Hardware gated PET/CT,which one is correct?
Reference:Walker MD, Morgan AJ, Bradley KM, McGowan DR. Data Driven Respiratory Gating Outperforms Device-Based Gating for Clinical FDG PET/CT. J Nucl Med. 2020.
Choice A:DDG PET/CT is better in image quality and lower in SUV than hardware gated PET/CT
Choice B:DDG PET/CT is better in image quality and higher in SUV than hardware gated PET/CT
Choice C:DDG PET/CT is worse in image quality and lower in SUV than hardware gated PET/CT
Choice D:DDG PET/CT is worse in image quality and higher in SUV than hardware gated PET/CT
Question 6: In comparison of PET/CT followed by either average CT or repeat PET/CT to correct for misregistration between CT and PET, which one of the following is correct?
Reference:Pan T, Lu Y, Thomas MA, Liao Z, Luo D. New data-driven gated PET/CT free of misregistration artifacts. Int. J Radiat Oncol Biol Phys. 109(5): 1638-1646. 2021. PMCID: PMC7965243.
Choice A:Average CT was lower in CT dose and shorter in scan time than repeat PET/CT
Choice B:Average CT was lower in CT dose and longer in scan time than repeat PET/CT
Choice C:Average CT was higher in CT dose and shorter in scan time than repeat PET/CT
Choice D:Average CT was higher in CT dose and longer in scan time than repeat PET/CT
Back to session list