Singapore legislation
Regulation 28
of Radiation Protection (Non-Ionising Radiation) Regulations
Regulation 28
Requirements for ultrasound apparatus
Subregulation 1
Every ultrasound apparatus shall be designed and constructed in such a manner that, under the conditions of use specified by the manufacturer, it functions in accordance with this regulation for as long as the apparatus has its original components or replacement components recommended by the manufacturer.
Subregulation 2
Every ultrasound apparatus shall be designed in such a manner that —
all marks, labels and signs are permanently affixed thereon and clearly visible; and
all user controls, meters, lights or other indicators are clearly visible, readily discernible and clearly labelled to indicate their function.
Subregulation 3
Every therapeutic ultrasound apparatus shall be designed and constructed to include the following features:
on the control panel, separate indicator lights or other equivalent indicators that have an expected lifetime of at least 5,000 hours —
to show when the line voltage is “ON” or “OFF”; and
to show when the ultrasonic power is being applied to the applicator;
a power indicator that —
in the case of an apparatus that produces a continuous wave, shows by a direct reading the level of the temporal maximum effective ultrasonic intensity; and
in the case of an apparatus that produces an amplitude modulated wave, shows by a direct reading the level of the temporal maximum ultrasonic power and the temporal maximum effective ultrasonic intensity;
a clear and reliable indicator of the range used, if the power indicator described in sub-paragraph (b) utilises 2 or more different ranges of measurement; and
a timer that —
terminates the generation of ultrasound after a preset time interval and then returns to zero;
does not allow the generation of ultrasound with the timer set at zero; and
is adjustable to settings in increments not greater than one minute.
Subregulation 4
Where a therapeutic ultrasound apparatus is equipped with an ultrasonic power control, that control shall —
allow the adjustment of ultrasonic power; and
have a minimum and maximum adjustment that directly relates to the ultrasonic power level indicator.
Subregulation 5
Except where an exemption has been granted by the Director‑General, every ultrasound apparatus shall function in such a manner that when the apparatus is operating with its user controls adjusted to yield maximum temporal average-spatial average effective ultrasonic intensity —
such intensity shall not exceed 30 kW/m2 for therapeutic ultrasound apparatus, when measured in accordance with paragraph (8); and
such intensity shall not exceed 1,000 W/m2, for diagnostic ultrasound apparatus, when measured in accordance with paragraph (8).
Subregulation 6
Diagnostic ultrasound apparatus shall be designed with adjustable controls so that the operator can use the minimum acoustic exposure required to image or obtain other information concerning the organ of interest in each patient.
Subregulation 7
Diagnostic ultrasound apparatus with output level exceeding 1,000 W/m2 if approved by the Director‑General shall include instruments for monitoring both exposure level and exposure time.
Subregulation 8
The method used to measure the effective ultrasonic intensity for the purposes of paragraph (7) shall produce a result that is at least as accurate as the result that will be produced by using —
an ultrasound balance radiometer to measure the ultrasonic power; and
an ultrasound detector of dimensions less than one wavelength in water to measure the pulse repetition rate, the pulse duration and the effective radiating area.
Subregulation 9
The power indicator referred to in paragraph (3)(b) for every therapeutic ultrasound apparatus shall show on the scale of the ultrasonic power control or on the output power meter the ultrasonic power with an accuracy of ± 20% when the output is greater than 10% of the maximum ultrasonic power.
Subregulation 10
The timer referred to in paragraph (3)(d) for every therapeutic ultrasound apparatus shall be accurate to within 30 seconds for setting less than 5 minutes, to within 10% for settings from 5 to 10 minutes, and to within one minute for setting greater than 10 minutes.
Subregulation 11
The ultrasonic power output shall remain constant within ± 20% of its initial value during one hour of continuous operation, at maximum output and at rated supply line voltage, in water at temperature of 22ºC ± 3ºC.
Subregulation 12
The actual ultrasonic frequency of a therapeutic ultrasound apparatus shall not differ more than ± 5% from the ultrasonic frequency of the apparatus that is stated on the external surface of the housing of the apparatus.
Subregulation 13
The effective radiating area shall be kept within ± 20% of the rated value given by the manufacturer.
Subregulation 14
Quality control procedures and testing programmes for the diagnostic ultrasound apparatus to ensure apparatus performance specifications are met shall be adopted by manufacturers and users.