Terason t3000, Руководство пользователя

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Chapter 12 - System Safety and Maintenance Safety Standards
Terason t3000 / Echo Ultrasound System User Guide 253
Ultrasound Safety
The following is a Prudent Use Statement regarding the use of ultrasound:
Use diagnostic ultrasound only when there is a good medical reason. Also, the Terason
Ultrasound System does not provide explicit control of acoustic power output.
Therefore, to minimize the exposure to ultrasound energy, limit the duration of
ultrasound examinations.
Electrical Safety
The Terason Ultrasound System conforms to the UL 60601-1 electrical safety standard.
Each transducer is insulated from the patient to minimize patient exposure in the presence
of a system fault or a fault in other patient-connected equipment. The type of protection
against electric shock is Class
I . The degree of protection is Type BF, per safety standard
IEC 60601-1.
To maintain compliance with electrical safety and emissions standards, the Terason
Ultrasound System must be used
only with the supplied Medical Grade Power Adapters.
Surface Heating of Invasive Transducers
The average and peak radiated acoustic powers of all Terason transducers are limited by
detection circuitry, to insure that the surface heating of the transducer array is less than
43ºC.
To limit the average acoustic power output, the maximum pulse repetition frequency
(PRF) is tested in hardware by comparing a PRF counter to a preset value. Exceeding the
maximum allowable PRF triggers an error message that displays on the host computer,
and the Terason Ultrasound System acoustic output is disabled. The preset maximum PRF
is chosen to limit the transducer case temperature to less than 43ºC when the transducer is
touching a patient.
The peak acoustic power is constrained by the maximum voltage applied to the
transducer-array elements. In hardware, peak power is monitored by a watchdog device
that measures instantaneous power and compares it to two thresholds. The first threshold
is a non-programmable four-watt limit. The second threshold is a programmable limit that
Terason has set in accordance with IEC 60601-2-37 and AIUM Nema UD2 and UD3
(1998 and 2004).