Specific Absorption Rate (SAR) and Specific Energy Dose (SED)

What does SAR (Specific Absorption Rate) specifically measure?. The total amount of energy deposited during an entire 45-minute exam. The rate at which RF energy is absorbed by the body, measured in Watts per kilogram (W/kg). The speed at which the MRI table moves into the bore. The strength of the static magnetic field in Tesla.

According to NEMA standards, RF heating is considered within safe levels if the patient's core temperature rise does not exceed: 0.1°C. 1.0°C. 5.0°C. 10.0°C.

What is the whole-body SAR limit for the "Normal Operating Mode" where no physiological stress is expected?. 1 W/kg. 8 W/kg. 4 W/kg. 2 W/kg.

In "First Level Controlled Mode," the whole-body SAR limit is 4 W/kg. What is required when operating in this mode?. The patient must be under general anesthesia. Medical supervision and control of physiological stress. The room lights must be turned off. A quench must be performed immediately after the scan.

Which of the following factors influences a patient's ability to cool themselves during an MRI?. Ambient room temperature and humidity. Patient health conditions like cardiovascular disease or diabetes. Medications such as beta-blockers or diuretics. All of the above.

How does Specific Energy Dose (SED) differ from SAR?. SED measures the magnetic field, while SAR measures the RF field. SED is the cumulative (total) dose of RF energy over the entire exam, while SAR is the rate per sequence. There is no difference; they are the same measurement. SED only applies to pediatric patients.

What is the standard unit of measurement for Specific Energy Dose (SED)?. Watts (W). Tesla (T). Joules per kilogram (J/kg) or Watts per minute per kilogram. Millimeters per second (mm/s).

At what SED level might patients with compromised thermoregulation (e.g., elderly, obese, or diabetic) begin to suffer physiological stress?. 100 J/kg. 1,000 J/kg. 6,000 J/kg. 50,000 J/kg.

According to IEC requirements, what must the MRI system do if the SED reaches the "hard stop" limit of 14,440 J/kg?. Display a small warning icon but continue scanning. Increase the scan speed. Stop scanning immediately and not allow the exam to continue. Automatically delete the images to save power.

If an MRI system reaches the 14,440 J/kg SED limit, how long is the "lock-out" period for that specific patient ID before they can be scanned again?. 1 hour. 12 hours. 24 hours. 7 days.