| Question 1: Dual energy CT capability to characterize different materials relies on |
| Reference: | C. McCollough, S. Leng, L. Yu, and J. Fletcher, Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. Radiology, Vol 276 (3), 2015 |
| Choice A: | Differences in attenuation properties at different X-ray energies |
| Choice B: | Compton scatter exclusively |
| Choice C: | Material-specific attenuation of the low-energy X-ray spectrum |
| Choice D: | The radiation dose |
| Question 2: Which of the following statements best describes the role of DECT-material-specific images in oncology is |
| Reference: | Mukta D. Agrawal, Daniella F. Pinho, Naveen M. Kulkarni, Peter F. Hahn, Alexander R. Guimaraes, Dushyant V. Sahani, Oncologic Applications of Dual-Energy CT in the Abdomen, RadioGraphics, Vo 34 (3), 2014 |
| Choice A: | Calcium and iodine separation remains difficult due to their almost similar attenuation |
| Choice B: | Material-specific images improve delineation of lesion borders and the assessment of local, vascular and soft tissue invasion |
| Choice C: | Iodine concentration contributes to chemotherapy selection |
| Choice D: | Iodine distribution guides modulation of dose for radiation therapy |
| Question 3: Which of the following is a potential limitation of DECT-material decomposition? |
| Reference: | Manuel Patino, Andrea Prochowski, Mukta D. Agrawal, Frank J. Simeone, Rajiv Gupta, Peter F. Hahn, Dushyant V. Sahani, Material Separation Using Dual-Energy CT: Current and Emerging Applications. RadioGraphics, Vol 36 (4), 2015 |
| Choice A: | The increase in conspicuity of iodine in lesions |
| Choice B: | Energy separation should be minimal to improve material characterization |
| Choice C: | Reliable discrimination of materials with similar atomic number |
| Choice D: | The algorithms generate images with different image texture, leading to longer learning curve during clinical adoption. |
| Question 4: Which of the following CT scanner platform cannot acquire more than 2 energy spectra within one single scan? |
| Reference: | R. Forghani, B. DeMan, G. Wang, “Dual-Energy Computed Tomography Physical Principles, Approaches to Scanning, Usage, and Implementation: Part 1”, Neuro imag Clin N Am 27 (2017) 371–384.
E. Dafni, D. Ruimi, “Multiple source CT scanner”, US Patent 5,966,422, 1999.
L. Yu, Z. Li, S. Leng, C. H. McCollough (2016). "Dual-source multi-energy CT with triple or quadruple x-ray beams." Proc SPIE 978312.
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| Choice A: | Multi-kVp imaging by switching the x-ray tube between multiple voltages |
| Choice B: | Dual-layer detector CT |
| Choice C: | Dual-source CT with split filters applied to one or both sources |
| Choice D: | Three-source CT |
| Question 5: Ideal PCD-CT is supposed to have better noise performance than energy-integrating detector (EID) based MECT techniques for material specific imaging. However, for current PCD-CT technology, the noise in material specific images is comparable to or even worse than that from some of the energy-integrating detector (EID) based MECT techniques, given the same total radiation dose. What is the primary reason? |
| Reference: | S. Faby, S. Kuchenbecker, et al. (2015). "Performance of today's dual energy CT and future multi energy CT in virtual non-contrast imaging and in iodine quantification: A simulation study." Medical physics 42(7): 4349-4366. |
| Choice A: | Spectral overlap in current PCD-CT is comparable to EID-based MECT |
| Choice B: | PCD-CT has a higher spatial resolution than EID-based CT |
| Choice C: | Signal to noise ratio of EID-based CT is better than PCD-CT |
| Choice D: | Signal to noise ratio of EID-based CT is worse than PCD-CT |
| Question 6: PCDs detect photons and measure their energies using: |
| Reference: | Vision 20/20: Single photon counting x-ray detectors in medical imaging. Taguchi K and Iwanczyk JS. Medical Physics, Vol 40, Issue 10, pp 100901 (19 pages), 2013. |
| Choice A: | Scintillator and photodiode |
| Choice B: | Gas and electrodes |
| Choice C: | Semiconductor-crystal and pulse height comparator in ASIC |
| Choice D: | Image intensifier and CCD camera |
| Question 7: Potential clinical merit of PCD-CT includes: |
| Reference: | Vision 20/20: Single photon counting x-ray detectors in medical imaging. Taguchi K and Iwanczyk JS. Medical Physics, Vol 40, Issue 10, pp 100901 (19 pages), 2013. |
| Choice A: | Short scan time duration |
| Choice B: | High contrast-to-noise ratio of images |
| Choice C: | Low soft tissue contrast |
| Choice D: | Low system cost |
| Question 8: Which of the followings is NOT an issue for clinical PCD-CT? |
| Reference: | Vision 20/20: Single photon counting x-ray detectors in medical imaging. Taguchi K and Iwanczyk JS. Medical Physics, Vol 40, Issue 10, pp 100901 (19 pages), 2013. |
| Choice A: | Cost of PCDs |
| Choice B: | Pulse pileups |
| Choice C: | Charge sharing and cross-talks |
| Choice D: | Light output efficiency |
| Question 9: Which feature is important for the contrast generation of an element in multi-energy CT: |
| Reference: | Si-Mohamed, S.; Bar-Ness, D.; Sigovan, M.; Cormode, D. P.; Coulon, P.; Coche, E.; Vlassenbroek, A.; Normand, G.; Boussel, L.; Douek, P. Review of an initial experience with an experimental spectral photon-counting computed tomography system. Nucl. Instr. Meth. Phys. Res. A 2017, 873, 27-35 |
| Choice A: | Their L-edge |
| Choice B: | Their K-edge |
| Choice C: | Double bonds |
| Choice D: | Electronegativity |
| Question 10: An advantage of multi-energy CT over conventional CT is: |
| Reference: | Dangelmaier, J.; Bar-Ness, D.; Daerr, H.; Muenzel, D.; Si-Mohamed, S.; Ehn, S.; Fingerle, A. A.; Kimm, M. A.; Kopp, F. K.; Boussel, L.; Roessl, E.; Pfeiffer, F.; Rummeny, E. J.; Proksa, R.; Douek, P.; Noel, P. B. Experimental feasibility of spectral photon-counting computed tomography with two contrast agents for the detection of endoleaks following endovascular aortic repair. Eur Radiol 2018. |
| Choice A: | Specific imaging of contrast agents |
| Choice B: | Fewer scans need to be done |
| Choice C: | The ability to distinguish different contrast agents |
| Choice D: | All of the above |
