Quiz: Cross Cutting & Emerging Technologies 1

Objectives: Although envisioned since the late 1980s, hybrid PET/MR systems only became commercially available in the last few years and more than a decade later than hybrid PET/CT. This is explained by the technological challenges originating from the combination of these two very different imaging modalities. Manifold interferences between the two modalities (in terms of B0, Gradient, RF, Temperature, Photon Attenuation, Space Constraints, Workflow, …) needed to identified, understood and solved.

1. What is (are) the key advantage(s) of hybrid PET/MR imaging?*

Reduced radiation dose (compared to PET/CT)
Simultaneous PET and MR acquisition
Better soft-tissue contrast in MRI compared to CT
Anatomical, functional and molecular information
All of the above

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2. Which of the following is not a disadvantage of sequential PET/MR?*

No simultaneity
Siting requirement
Compromise of PET and MRI performance
Scan time

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3. Which of the following is not a hardware challenge when combining PET and MR?*

PET interferences caused by MR
MR interferences caused by PET
Ionizing radiation during PET imaging
RF shielding
Tight space

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4. Which of the following is not a major challenge of PET/MR attenuation correction?*

There is a plurality of MR contrasts but no/weak correlation to PET photon attenuation.
Conversion of attenuation of low energy photon to PET energy (511keV)
MR signals are typically relative and depend on prescan settings, and B1 and B0 inhomogeneity.
Gradient non-linearities lead to geometric distortions and truncation.

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