| Question 1: When the maximum slew rate of an MR gradient system is increased: |
| Reference: | Tan ET, Lee SK, Weavers PT, Graziani D, Piel JE, Shu Y, Huston J 3rd, Bernstein MA, Foo TK. High slew-rate head-only gradient for improving distortion in echo planar imaging: Preliminary experience. J Magn Reson Imaging. 2016 Sep; 44(3): 653-64. doi: 10.1002/jmri.25210. |
| Choice A: | The minimum echo time (TE) will decrease for diffusion imaging. |
| Choice B: | The number of liters of liquid helium will decrease. |
| Choice C: | The minimum echo spacing will increase. |
| Choice D: | The number of RF channels will increase. |
| Question 2: An asymmetric gradient design improves patient access within a smaller diameter bore, but also introduces: |
| Reference: | Tao S, Trzasko JD, Gunter JL, Weavers PT, Shu Y, Huston J, Lee SK, Tan ET, Bernstein MA. Gradient nonlinearity calibration and correction for a compact, asymmetric magnetic resonance imaging gradient system. Phys Med Biol. 2017; 62(2): N18-N31. doi: 10.1088/1361-6560/aa524f. |
| Choice A: | Passive shimming. |
| Choice B: | A higher bandwidth receiver and sampling rate. |
| Choice C: | A vent stack for the cryogens. |
| Choice D: | Even-order gradient non-linearity terms. |
| Question 3: By reducing the liquid helium requirement from 1500 to 12 liters, a compact MRI might not require a: |
| Reference: | Foo TKF, Laskaris E, Vermilyea M, Xu M, et al. Lightweight, compact, and high-performance 3T MR system for imaging the brain and extremities. Magn Reson Med. 2018 Mar 13. doi: 10.1002/mrm.27175. [Epub ahead of print] |
| Choice A: | Vent stack. |
| Choice B: | Superconductor. |
| Choice C: | High-voltage gradient amplifier. |
| Choice D: | Freight elevator. |
| Question 4: What is the primary advantage of a PET scanner with a long axial field-of-view? |
| Reference: | Cherry et al. Total-Body PET: Maximizing Sensitivity to create new opportunities for Clinical Research and Patient Care. J Nucl Med ;59(1):3-12; Jan 2018. |
| Choice A: | The sensitivity is an order of magnitude higher than a commercial PET scanner. |
| Choice B: | The TOF resolution is better. |
| Choice C: | The quantitative accuracy is improved due to the large axial acceptance of coincident gammas. |
| Choice D: | It does not require a CT scan for attenuation correction. |
| Question 5: Which of the following are advantages of silicon photo-multipliers compared to vacuum-tube photo-multipliers? |
| Reference: | Vandenberghe et al. Time-of-flight PET: a review of different benefits and recent developments in time-of-flight PET. Euro J Nucl Med, 3: Dec 2015. |
| Choice A: | They can be incorporated into PET/MR scanners. |
| Choice B: | They lead to improved timing resolution in TOF PET scanners. |
| Choice C: | They can be used in small animal PET scanners. |
| Choice D: | All of the above. |
| Question 6: Improved time-of-flight resolution leads to which of the following? |
| Reference: | Surti S. Update on Time-of-Flight PET Imaging. J Nucl Med, 56(1): 98-105, Jan 2015. |
| Choice A: | Improved spatial resolution. |
| Choice B: | Increased scan counts. |
| Choice C: | Improved image signal-to-noise. |
| Choice D: | All of the above. |
| Question 7: What major hardware modification in converting a conventional FFDM to multi-contrast x-ray breast imaging system? |
| Reference: | Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources, Franz Pfeiffer; Timm Weitkamp; Oliver Bunk; and Christian David, Nature Physics, Vol 2, pp 258, 2006 |
| Choice A: | Replacement of the Detector. |
| Choice B: | Replacement of the X-ray tube. |
| Choice C: | Modify the SDD. |
| Choice D: | Incorporate three x-ray gratings. |
| Question 8: What is the major technical challenge in constructing the multi-contrast x-ray breast imaging prototype system? |
| Reference: | Tomography with grating interferometers at low-brilliance sources, Timm Weitkamp; Christian David; Christian Kottler; Oliver Bunkc; and Franz Pfeiffer, Proc. SPIE, Vol 6318, pp S3180S, 2006 |
| Choice A: | Limited source-to-detector distance for the mammography system. |
| Choice B: | Polychromatic x-ray spectrum of the mammography system. |
| Choice C: | Finite focal spot size of the x-ray tube. |
| Choice D: | All of the above. |
| Question 9: What are the primary benefits of CMOS X-ray detector compared to amorphous silicon Flat-Panel Detectors in high-resolution orthopedic imaging? |
| Reference: | Modeling and Evaluation of a High-Resolution CMOS Detector for Cone-Beam CT of the Extremities, Q. Cao; A, Sisniega; M. Brehler; JW. Stayman; J. Yorkston; J.H.Siewerdsen; W. Zbijewski; Medical Physics 45, 114–130, 2018 |
| Choice A: | Faster readout. |
| Choice B: | Smaller pixel size. |
| Choice C: | Lower electronic noise. |
| Choice D: | All of the above. |
| Question 10: For a CMOS detector with ~100 µm pixels, scintillator (CsI) thickness has the following effect on detectability in a discrimination task with two Gaussian stimuli of different width: |
| Reference: | Modeling and Evaluation of a High-Resolution CMOS Detector for Cone-Beam CT of the Extremities, Q. Cao; A, Sisniega; M. Brehler; JW. Stayman; J. Yorkston; J.H.Siewerdsen; W. Zbijewski; Medical Physics 45, 114–130, 2018 |
| Choice A: | Thinner scintillator always improves detectability because of better spatial resolution . |
| Choice B: | Thicker scintillator always improves detectability because of reduced noise. |
| Choice C: | Thicker scintillator is preferred for low-resolution tasks (coarse stimuli). |
| Choice D: | Scintillator thickness has no effect on detectability. |
