8.8.6 Medical Equipment
Medical equipment requires the assessment objective to be stated precisely. Intended RF exposure of a patient during recognized medical diagnosis or treatment is governed by the relevant medical-device and clinical requirements. RPS S-1 does not apply its exposure limits to that patient medical exposure, but it does apply to people operating the radiating equipment and to others in the vicinity during the procedure.
The assessor should therefore distinguish intended patient exposure from stray or occupational exposure of operators, other staff, visitors, and the public. Equipment type, applicator or coil geometry, operating mode, duty cycle, treatment power, shielding, and staff positions determine the appropriate survey. MRI facilities also involve static magnetic and switched-gradient fields; those hazards require their own assessment, while this chapter addresses the RF component.
Measurements around diathermy, MRI, electrosurgical, and other RF medical systems may require source-specific probes, standardized test arrangements, or computational methods. Public or occupational RF limits should not be used as a substitute for evaluating the intended clinical exposure of the patient.
8.8.7 Consumer And Close-Body Wireless Devices
Fixed consumer devices used at appreciable separation, such as some wireless access points, may be assessed using conventional field measurements or conservative calculations. Hand-held, body-worn, body-supported, and other close-body transmitters produce highly nonuniform fields and usually require a standardized product-compliance method rather than a free-space survey.
Depending on frequency and the applicable exposure restriction, close-body assessment may determine specific absorption rate, absorbed power density, or incident power density using standardized phantoms, laboratory measurement systems, or validated computational models. The test configuration must represent the intended use, including separation distance, accessories, antenna position, power control, duty cycle, and simultaneous transmission from multiple radios.
A low-power exclusion or other simplified assessment may be used only where the applicable standard or regulatory procedure permits it. Otherwise, the device should be evaluated under the prescribed operating and measurement conditions.