| Question 1: A change to which of the following parameters will alter CT number and have the most impact on a dosimetry plan? |
| Reference: | From Chapter 9, “Beam Energy, CT Number, and Dual Energy CT,” of The CT Handbook: Optimizing Protocols for Today’s Feature-Rich Scanners. Medical Physics Publishing 2020. |
| Choice A: | Reconstruction kernel |
| Choice B: | Beam energy |
| Choice C: | Bowtie filter size and composition |
| Choice D: | Patient positioning within the gantry |
| Question 2: Which automatic exposure control feature is most likely to be turned off by a radiation oncology physicist who needs consistent CT numbers? |
| Reference: | From Chapter 7, “Automatic Exposure Control,” of The CT Handbook: Optimizing Protocols for Today’s Feature-Rich Scanners. Medical Physics Publishing 2020. |
| Choice A: | Tube current modulation |
| Choice B: | Rotation time selection |
| Choice C: | Helical/spiral pitch selection |
| Choice D: | Beam energy selection |
| Question 3: Challenges in CBCT imaging for radiotherapy localization include which of the following? |
| Reference: | 1. Mail, N., et al. "The influence of bowtie filtration on cone‐beam CT image quality." Medical Physics 36(1):22-32 (2009).
2. Bissonnette, Jean‐Pierre, Douglas J. Moseley, and David A. Jaffray. "A quality assurance program for image quality of cone‐beam CT guidance in radiation therapy." Medical physics 35(5):1807-1815 (2008).
3. Veiga, Catarina, et al. "Toward adaptive radiotherapy for head and neck patients: feasibility study on using CT‐to‐CBCT deformable registration for “dose of the day” calculations." Medical Physics 41(3):031703 (2014). |
| Choice A: | Scatter radiation due to cone-beam geometry |
| Choice B: | Non-uniform x-ray fluence at the detector plane |
| Choice C: | Motion of the patient |
| Choice D: | Limited field-of-view |
| Choice E: | All of the above |
| Question 4: The use of an iterative cone-beam CT (iCBCT) algorithm has the potential to improve image quality for what percentage (approximately) of H&N and prostate cancer patients? |
| Reference: | Gardner, Stephen J., et al. "Improvements in CBCT image quality using a novel iterative reconstruction algorithm: a clinical evaluation." Advances in Radiation Oncology 4(2):390-400 (2019). |
| Choice A: | 30% |
| Choice B: | 50% |
| Choice C: | 70% |
| Choice D: | 90% |
| Question 5: Beside magnetic field inhomogeneity, which of the following can cause geometric distortion in MRI images? |
| Reference: | Price RG, Kadbi M, Kim J, Balter J, Chetty IJ, Glide-Hurst CK. Characterization and correction of gradient nonlinearity induced distortion on a 1.0 T open bore MR-SIM. Medical Physics. 2015 Oct;42(10):5955-60. |
| Choice A: | Patient motion |
| Choice B: | Insufficient gradient strength |
| Choice C: | Gradient nonlinearity |
| Choice D: | Long echo times |
| Question 6: Use of immobilization devices can increase the distance between the patient and receiving RF coils. Which of the following is impacted as a result? |
| Reference: | Paulson ES, Erickson B et al. Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning. Med Phys 2015 Jan;42(1):28-39 |
| Choice A: | It decreases image signal to noise ratio |
| Choice B: | It increases image signal to noise ratio |
| Choice C: | It reduces geometric distortion |
| Choice D: | It increases geometric distortion |
| Question 7: Which FDG PET/CT imaging window for assessing cancer response during conventionally fractionated radiation therapy mitigates the risk of confounding tissue inflammation? |
| Reference: | Bissonnette JP, Yap ML, Clarke K, Shessel A, Higgins J, Vines D, Atenafu EG, Becker N, Leavens C, Bezjak A, Jaffray DA, Sun A. Serial 4DCT/4DPET imaging to predict and monitor response for locally-advanced non-small cell lung cancer chemo-radiotherapy. Radiother Oncol. 2018 Feb;126(2):347-354. doi: 10.1016/j.radonc.2017.11.023. Epub 2017 Dec 12. |
| Choice A: | Baseline |
| Choice B: | 1-3 weeks |
| Choice C: | 4-6 weeks |
| Choice D: | 6-8 weeks |
| Question 8: Which radiation treatment strategy presents the greatest challenge to quantitative FDG PET/CT imaging? |
| Reference: | Bentzen SM. Theragnostic imaging for radiation oncology: dose-painting by numbers. Lancet Oncol. 2005 Feb;6(2):112-7. |
| Choice A: | Uniform radiation dose to anatomic target volumes |
| Choice B: | Simultaneous integrated radiation dose boosting |
| Choice C: | Spatially non-uniform radiation dose scaled by target voxel biological disease burden |
| Choice D: | Uniform radiation dose to metabolic target volumes |
| Question 9: Signal to noise ratio (SNR) of PET is a function of sensitivity (S), injected activity (A) and scan time (T) through the following relationship: |
| Reference: | Simon R. Cherry, Terry Jones, Joel S. Karp, Jinyi Qi, William W. Moses, and Ramsey D. Badawi. “Total-Body PET: Maximizing Sensitivity to Create New Opportunities for Clinical Research and Patient Care” J Nuc Med 59(1):3-12, 2018. |
| Choice A: | SNR ~ √(S x A x T) |
| Choice B: | SNR ~ S x A x T |
| Choice C: | SNR ~ A x √( S x T) |
| Choice D: | SNR ~ S x √( A x T) |
| Question 10: When a repeat scan is suggested for fixing mis-registration between CT and PET images in PET/CT, which one 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: | Both CT and PET should be repeated |
| Choice B: | Only CT should be repeated |
| Choice C: | Only PET should be repeated |
| Choice D: | Either CT or PET should be repeated |
