| Question 1: How are thermoacoustic emissions produced during pulsed irradiation of ionizing radiation for therapeutic and diagnostic imaging applications? |
| Reference: | Susannah Hickling, Liangzhong Xiang, Kevin C. Jones, Katia Parodi, Walter Assmann, Stephen Avery, Maritza Hobson, Issam El Naqa: Ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications. Medical Physics 45(7): e707-e721, April 2018. |
| Choice A: | Upon tissue irradiation, a localized (in space and time) energy deposition can lead to a thermal expansion and related acoustic emissions, with properties depending on the initial beam characteristics (especially energy deposition pattern and time profile) |
| Choice B: | Upon irradiation, secondary electrons and related Cherenkov emissions produce optical photons which can be absorbed by special dyes, resulting in localized photoacoustic emissions in a pre-selected frequency range |
| Choice C: | Upon tissue irradiation from radiofrequency driven accelerators, acoustic waves result from constructive interferences between the oscillating nature of the radiation field and characteristic frequencies of physiological processes, especially heart beat |
| Choice D: | Thermoacoustic emissions can only be produced by continuous beams of ionizing irradiation |
| Question 2: Which is the instrumentation of choice to monitor ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications? |
| Reference: | Susannah Hickling, Liangzhong Xiang, Kevin C. Jones, Katia Parodi, Walter Assmann, Stephen Avery, Maritza Hobson, Issam El Naqa: Ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications. Medical Physics 45(7): e707-e721, April 2018. |
| Choice A: | Standard clinical ultrasonic transducers, which offer a well proven solution of optimal sensitivity and bandwidth |
| Choice B: | Cardiac or small animal ultrasonic transducers are needed, to offer ultrahigh frequency operation at excellent spatial resolution |
| Choice C: | Dedicated broadband ultrasound transducers of high sensitivity and properly chosen central frequency are preferable due to the typically lower frequency range of thermoacoustic emissions induced by clinically used ionizing radiation, compared to clinical ultrasound imaging |
| Choice D: | No instrumentation yet exists, which is able to detect the theoretical presence of ionizing radiation-induced acoustic emissions |
| Choice E: | None of the above |
| Question 3: Which of the following properties is the induced acoustic signal NOT dependent on? |
| Reference: | Susannah Hickling, Liangzhong Xiang, Kevin C. Jones, Katia Parodi, Walter Assmann, Stephen Avery, Maritza Hobson, Issam El Naqa: Ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications. Medical Physics 45(7): e707-e721, April 2018. |
| Choice A: | Dose |
| Choice B: | Density |
| Choice C: | Speed of sound |
| Choice D: | Dose rate |
| Question 4: The proton-induced acoustic pressure is proportional to : |
| Reference: | Susannah Hickling, Liangzhong Xiang, Kevin C. Jones, Katia Parodi, Walter Assmann, Stephen Avery, Maritza Hobson, Issam El Naqa: Ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications. Medical Physics 45(7): e707-e721, April 2018 |
| Choice A: | The pulse duration of the proton beam |
| Choice B: | The deposited proton dose in the tissue |
| Choice C: | The energy of the particles |
| Choice D: | None of the above |
| Question 5: What is the typical rise time necessary to generate a thermo-acoustic pulse? |
| Reference: | Susannah Hickling, Liangzhong Xiang, Kevin C. Jones, Katia Parodi, Walter Assmann, Stephen Avery, Maritza Hobson, Issam El Naqa: Ionizing radiation-induced acoustics for radiotherapy and diagnostic radiology applications. Medical Physics 45(7): e707-e721, April 2018 |
| Choice A: | 10 ms |
| Choice B: | 10 ns |
| Choice C: | 10 µs |
| Choice D: | 10 s |
| Question 6: Which statement is NOT true regarding the potential therapeutic application of Cherenkov light (CL) produced by a megavoltage (MV) treatment beam ? |
| Reference: | Yoon et al., Enhancing Radiation Therapy Through Cherenkov Light-Activated Phototherapy, Int J Radiat Oncol Biol Phys, 2018, Mar 1;100(3):794-801. |
| Choice A: | CL is produced throughout the beam path in proportion to absorbed dose |
| Choice B: | The magnitude of CL production increases with higher beam energy |
| Choice C: | CL alone can achieve clinical effect, without the need for a photo-therapeutic |
| Choice D: | CL is strongly peaked in the ultra-violet (UV) realm |
| Question 7: What are the potential advantages of simultaneous combination of radiation therapy and photo-activated psoralen? |
| Reference: | Yoon et al., Enhancing Radiation Therapy Through Cherenkov Light-Activated Phototherapy, Int J Radiat Oncol Biol Phys, 2018, Mar 1;100(3):794-801. |
| Choice A: | Increased immunogenic therapeutic response |
| Choice B: | Shorter treatment times |
| Choice C: | Reduced radiation dose for same clinical effect |
| Choice D: | (A) and (C) |
| Question 8: What are the correction factors necessary to convert from Cherenkov intensity to radiation dose: |
| Reference: | Xie Y, Petroccia H, Maity A, Miao T, Zhu Y, Bruza P, Pogue BW, Plastaras JP, Dong L, Zhu TC. Cherenkov imaging for total skin electron therapy (TSET). Med Phys. 2020 Jan;47(1):201-212. doi: 10.1002/mp.13881. Epub 2019 Nov 26. PubMed PMID: 31665544; PubMed Central PMCID: PMC7050296 |
| Choice A: | Perspective correction factor |
| Choice B: | Inverse square correction factor |
| Choice C: | Tissue optical properties correction factor |
| Choice D: | All of the above |
| Question 9: Cherenkov light emission during external beam radiotherapy has NOT been observed readily because: |
| Reference: | B W Pogue, R Zhang, A Glaser, J M Andreozzi, P Bruza, D J Gladstone, L A Jarvis, “Cherenkov imaging in the potential roles of radiotherapy QA and delivery” Journal of Physics: Conference Series, Volume 847, 9th Int Conf 3D Radiat Dosimetry 7–10 Nov 2016, TX USA, Published 1 May 2017 (IOP Publishing Ltd) https://iopscience.iop.org/article/10.1088/1742-6596/847/1/012046 |
| Choice A: | The light is ultraviolet and therefore invisible |
| Choice B: | There is nobody in the room during treatment. |
| Choice C: | The light occurs just during the linac pulses and the duty cycle is very low. |
| Choice D: | The light intensity occurs at a level below the visible detection limit. |
| Question 10: Cerenkov radiation can potentially be used to achieve better timing performance in positron emission tomography because: |
| Reference: | Kwon SI, Gola A, Ferri A, Piemonte C, Cherry SR. Bismuth germanate coupled to near ultraviolet silicon photomultipliers for time-of-flight PET. Phys Med Biol 2016; 61: L38-L47. |
| Choice A: | It is brighter than conventional scintillation light |
| Choice B: | It is preferentially emitted in the ultra-violet part of the spectrum |
| Choice C: | It is emitted promptly upon interaction of a 511 keV photon |
| Choice D: | It has a higher velocity than scintillation light |
