If a device's MR conditions state that it can only safely be scanned at 1.5 T in normal operating mode, can it be scanned at a resonant frequency of 128 MHz?

The correct choice emphasizes the safety parameters determined by the manufacturer for the device. If the MR conditions specify that the device is only safe to be scanned at 1.5 T (Tesla), it implies that at this magnetic field strength, the device's functionality and safety have been validated.

In terms of resonant frequency, 1.5 T corresponds to approximately 64 MHz for protons in MRI. Consequently, if the device is described to operate in normal mode only at 1.5 T, then it cannot be scanned at 128 MHz, which corresponds to a much higher magnetic field strength of 3 T (Tesla), where the device has not been validated for use. Therefore, attempting to scan the device at a resonant frequency of 128 MHz would exceed the established safety limits, potentially risking device malfunction or safety hazards.

This understanding underscores the importance of adhering strictly to the manufacturer's specified conditions for safe operation in MR environments.