RF Coils and Safety

According to the video, which type of RF coil is of primary concern for MR safety in most clinical situations regarding heat and energy deposition?. Receive-only coils. Transmit-capable coils. Surface coils. Linear polarized receiver coils.

What is a significant disadvantage of using a linearly polarized transmit coil compared to a circularly polarized (CP) coil?. They are too expensive to manufacture. They produce a higher signal-to-noise ratio. Half of their power is essentially wasted, resulting in higher SAR. They cannot be used in superconducting magnets.

Why is it critical to ensure a receive-only coil is always connected to the MR system during a scan?. To improve the image resolution. To allow the software to detune the coil during RF transmission. To prevent the patient from feeling claustrophobic. To calibrate the static magnetic field ($B_0$).

What is another common name for a "circularly polarized" coil?. Linear coil. Quadrature coil. Multi-transmit coil. Parallel receive coil.

What is a "birdcage" design typically associated with?. The cooling system of the magnet. A common design for circularly polarized or quadrature coils. A type of lead shielding for the scan room. The patient table movement mechanism.

In the context of multi-transmit technology, what is one of the primary benefits mentioned?. Reduced scan time by 90%. Lowering static magnetic field strength. Significant reduction in dielectric shading. Elimination of the need for cryogens.

If an implant's safety conditions specify "Quadrature Transmit Only," what should a technologist do if their system uses multi-transmit technology?. Cancel the scan immediately. Switch the system to a quadrature or CP transmit mode. Increase the SAR limit to compensate. Ignore the instruction as multi-transmit is always safer.

When a receive-only coil is used, what component of the MR system usually performs the RF transmission?. The gradient coils. The integrated RF body coil. The patient's ECG leads. The shim coils.

Which subfield of a linearly polarized transmit coil is effective at inducing nuclear transitions for NMR?. The negative rotating subfield. The positive rotating subfield. Both the positive and negative subfields. Neither; linear coils do not use subfields.

True or False: You can always determine if a coil is transmit-receive or receive-only just by looking at its external appearance. True. False.