2022 AAPM 64th Annual Meeting
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Session Title: Fundamentals of Photon-Counting CT
Question 1: A typical range of photon flux in clinical CT is:
Reference:Persson, M., Bujila, R., Nowik, P., Andersson, H., Kull, L., Andersson, J., Bornefalk, H. and Danielsson, M., 2016. Upper limits of the photon fluence rate on CT detectors: case study on a commercial scanner. Medical physics, 43(7), pp.4398-4411.
Choice A:10^12 – 10^17 photons/ mm2 / s
Choice B:10^2 – 10^4 photons/ mm2 / s
Choice C:105 – 108 photons/ mm2/ s
Choice D:10^8 – 10^12 photons/ mm2 / s
Question 2: Pulse pileup in photon-counting detector leads mainly to:
Reference:Danielsson, M., Persson, M. and Sjölin, M., 2021. Photon-counting x-ray detectors for CT. Physics in Medicine & Biology, 66(3), p.03TR01.
Choice A:Reduced spatial resolution
Choice B:Reduced CNR
Choice C:Reduced spectral resolution
Choice D:Both A and B
Choice E:Both B and C
Choice F:Both A and C
Question 3: Photon counting detectors offer the least advantage over energy-integrating detectors for the imaging task:
Reference:Pourmorteza, A., Symons, R., Reich, D.S., Bagheri, M., Cork, T.E., Kappler, S., Ulzheimer, S. and Bluemke, D.A., 2017. Photon-counting CT of the brain: in vivo human results and image-quality assessment. American Journal of Neuroradiology, 38(12), pp.2257-2263. Willemink, M.J., Persson, M., Pourmorteza, A., Pelc, N.J. and Fleischmann, D., 2018. Photon-counting CT: technical principles and clinical prospects. Radiology, 289(2), pp.293- 312.Irradiation and Immunotherapy: From Concept to the Clinic, April K. S. Salama, MD; Michael A. Postow, MD; and Joseph K. Salama, MD Cancer, Vol 122, Issue 11, pp 1659-1671, 2016
Choice A:Differentiating calcified from fatty coronary plaques
Choice B:Detection of bone edema
Choice C:Detecting temporal bone erosion
Choice D:Differentiating gray and white matter in the brain
Question 4: Compared to energy-integration detector, the uniform photon energy (spectral) weighting in PCDs results in:
Reference:Gutjahr et al. Invest Radiol. 2016 Jul;51(7):421-9.
Choice A:Improved image contrast-to-noise ratio
Choice B:Reduced image artifacts
Choice C:Improved spectral resolution
Choice D:None of the above
Question 5: The absence of reflective interpixel septae in PCDs lead to:
Reference:Leng et al. J Med Imaging. 2016 Oct; 3(4): 043504
Choice A:Increased geometric dose efficiency
Choice B:Reduced charge sharing
Choice C:Direct conversion of x-rays to electric signals
Choice D:None of the above
Question 6: The conditioning of material decomposition in photon-counting CT is determined by:
Reference:Tang X. and Ren Y. (2020) "On the conditioning of basis materials and its impact on multi-material decomposition based spectral imaging in photon-counting CT,” Medical Physics, 2021;48(3), 1100-1116. Ren Y, Xie H, Long W, Yang X and Tang X (2020) "On the conditioning of spectral channelization (energy binning) and its impact on multi-material decomposition based spectral imaging in photon-counting CT,” IEEE Transactions on Biomedical Engi., 68(9), pp.2678-2688, 2021.
Choice A:Correlation between the attenuation property of basis materials
Choice B:Spectral overlapping between abutted spectral channels
Choice C:Both a and b
Choice D:None of the above
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