[Code of Federal Regulations]
[Title 21, Volume 8]
[Revised as of April 1, 2001]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR1050.10]
[Page 633-636]
TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN
SERVICES--(Continued)
PART 1050--PERFORMANCE STANDARDS FOR SONIC, INFRASONIC, AND ULTRASONIC RADIATION-EMITTING PRODUCTS--Table of Contents
Sec. 1050.10 Ultrasonic therapy products.
(a) Applicability. The provisions of this section are applicable as
specified herein to any ultrasonic therapy product for use in physical
therapy manufactured on or after February 17, 1979.
(b) Definitions. The following definitions apply to words and
phrases used in this section:
(1) Amplitude modulated waveform means a waveform in which the ratio
of the temporal-maximum pressure amplitude spatially averaged over the
effective radiating surface to the root-mean-square pressure amplitude
spatially averaged over the effective radiating surface is greater than
1.05.
(2) Applicator means that portion of a fully assembled ultrasonic
therapy product that is designed to emit ultrasonic radiation and which
includes one or more ultrasonic transducers and any associated housing.
(3) Beam cross-section means the surface in any plane consisting of
the points at which the intensity is greater than 5 percent of the
spatial-maximum intensity in that plane.
(4) Beam nonuniformity ratio means the ratio of the temporal-average
spatial-maximum intensity to the temporal-average effective intensity.
(5) Centroid of a surface means the point whose coordinates are the
mean values of the coordinates of the points of the surface.
(6) Collimating applicator means an applicator that does not meet
the definition of a focusing applicator as specified in paragraph
(b)(15) of this section and for which the ratio of the area of at least
one beam cross-section, whose centroid is 12 centimeters from the
centroid of the effective radiating surface, to the area of the
effective radiating surface is less than two.
(7) Continuous-wave waveform means a waveform in which the ratio of
the temporal-maximum pressure amplitude spatially averaged over the
effective radiating surface to the root-mean-square pressure amplitude
spatially averaged over the effective radiating surface is less than or
equal to 1.05.
(8) Diverging applicator means an applicator that does not meet the
definition of a collimating applicator or a focusing applicator as
specified in paragraphs (b) (6) and (15) of this section.
(9) Effective intensity means the ratio of the ultrasonic power to
the focal area for a focusing applicator. For all other applicators, the
effective intensity is the ratio of the ultrasonic power to the
effective radiating area. Effective intensity is expressed in watts per
square centimeter (W cm-2).
(10) Effective radiating area means the area consisting of all
points of the effective radiating surface at which the intensity is 5
percent or more of the maximum intensity at the effective radiating
surface, expressed in square centimeters (cm2).
(11) Effective radiating surface means the surface consisting of all
points 5 millimeters from the applicator face.
(12) Focal area means the area of the focal surface, expressed in
square centimeters (cm2).
(13) Focal length means the distance between the centroids of the
effective radiating surface and the focal surface, for a focusing
applicator, expressed in centimeters (cm).
(14) Focal surface means the beam cross-section with smallest area
of a focusing applicator.
(15) Focusing applicator means an applicator in which the ratio of
the area of the beam cross-section with the smallest area to the
effective radiating area is less than one-half.
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(16) Generator means that portion of a fully assembled ultrasonic
therapy product that supplies electrical energy to the applicator. The
generator may include, but is not limited to, a power supply, ultrasonic
frequency oscillator, service controls, operation controls, and a
cabinet to house these components.
(17) Maximum beam nonuniformity ratio means the maximum value of the
beam nonuniformity ratio characteristic of a model of an ultrasonic
therapy product.
(18) Operation control means any control used during operation of an
ultrasonic therapy product that affects the ultrasonic radiation emitted
by the applicator.
(19) Pressure amplitude means the instantaneous value of the
modulating waveform, and is p1(t) in the expression for a
pressure wave, p(t)=p1(t) p2(t), where p(t) is the
instantaneous pressure, p1(t) is the modulating envelope, and
p2(t) is the relative amplitude of the carrier wave
normalized to a peak height of one. All are periodic functions of time,
t, at any point in space. The period of p1(t) is greater than
the period of p2(t).
(20) Pulse duration means a time interval, expressed in seconds,
beginning at the first time the pressure amplitude exceeds the minimum
pressure amplitude plus 10 percent of the difference between the maximum
and minimum pressure amplitudes, and ending at the last time the
pressure amplitude returns to this value.
(21) Pulse repetition rate means the repetition frequency of the
waveform modulating the ultrasonic carrier wave expressed in pulses per
second (pps).
(22) Service control means any control provided for the purpose of
adjustment that is not used during operation and can affect the
ultrasonic radiation emitted by the applicator, or can alter the
calibration or accuracy of an indicator or operation control.
(23) Ultrasonic frequency means the frequency of the ultrasonic
radiation carrier wave, expressed in Hertz (Hz), kilohertz (kHz), or
megahertz (MHz).
(24) Ultrasonic power means the total power emitted in the form of
ultrasonic radiation by the applicator averaged over each cycle of the
ultrasonic radiation carrier wave, expressed in watts.
(25) Ultrasonic therapy product means:
(i) Any device intended to generate and emit ultrasonic radiation
for therapeutic purposes at ultrasonic frequencies above 16 kilohertz
(kHz); or
(ii) Any generator or applicator designed or specifically designated
for use in a device as specified in paragraph (b)(25)(i) of this
section.
(26) Ultrasonic transducer means a device used to convert electrical
energy of ultrasonic frequency into ultrasonic radiation or vice versa.
(c) Performance requirements. The requirements of this paragraph are
applicable to each ultrasonic therapy product as defined in paragraph
(b)(25) of this section when the generator and applicator are designated
or intended for use together, or to each generator when the
applicator(s) intended for use with the generator does not contain
controls that affect the functioning of the generator.
(1) Ultrasonic power and intensity--(i) Continuous-wave waveform
operation. A means shall be incorporated to indicate the magnitudes of
the temporal-average ultrasonic power and the temporal-average effective
intensity when emission is of continuous-wave waveform. The error in the
indication of the temporal-average ultrasonic power shall not exceed
plus-minus20 percent for all emissions greater than 10
percent of the maximum emission.
(ii) Amplitude-modulated waveform operation. A means shall be
incorporated to indicate the magnitudes of the temporal-maximum
ultrasonic power and the temporal-maximum effective intensity when the
emission is of amplitude-modulated waveform. The sum of the errors in
the indications of the temporal-maximum ultrasonic power and the ratio
of the temporal-maximum effective intensity to the temporal-average
effective intensity specified in paragraph (d)(3)(ii) of this section
shall not exceed plus-minus20 percent for all emissions
greater than 10 percent of the maximum emission.
(2) Treatment time. A means shall be incorporated to enable the
duration of emission of ultrasonic radiation for treatment to be preset
and such means shall terminate emission at the end of
[[Page 635]]
the preset time. Means shall also be incorporated to enable termination
of emission at any time. Means shall be incorporated to indicate the
magnitude of the duration of emission (expressed in minutes) to within
0.5 minute of the preset duration of emission for setting less than 5
minutes, to within 10 percent of the preset duration of emission for
settings of from 5 minutes to 10 minutes, and to within 1 minute of the
preset duration of emission for settings greater than 10 minutes.
(3) Pulse duration and repetition rate. A means shall be
incorporated for indicating the magnitudes of pulse duration and pulse
repetition rate of the emitted ultrasonic radiation, if there are
operation controls for varying these quantities.
(4) Ultrasonic frequency. A means shall be incorporated for
indicating the magnitude of the ultrasonic frequency of the emitted
ultrasonic radiation, if there is an operation control for varying this
quantity.
(5) Visual indicator. A means shall be incorporated to provide a
clear, distinct, and readily understood visual indicator when and only
when electrical energy of appropriate ultrasonic frequency is being
applied to the ultrasonic transducer(s).
(d) Labeling requirements. In addition to the labeling requirements
in part 801 and the requirements of Secs. 1010.2 and 1010.3 of this
chapter, each ultrasonic therapy product shall be subject to the
applicable labeling requirements of this paragraph.
(1) Operation controls. Each operation control shall be clearly
labeled identifying the function controlled and, where appropriate, the
units of measure of that function. If a separate control and indicator
are associated with the same function, then labeling the appropriate
units of measure of that function is required for the indicator but not
for the control.
(2) Service controls. Each service control that is accessible
without displacement or removal of any part of the ultrasonic therapy
product shall be clearly labeled identifying the function controlled and
shall include the phrase ``for service adjustment only.''
(3) Generators. (i) Each generator shall bear a label that states:
The brand name, model designation, and unique serial number or other
unique identification so that it is individually identifiable;
ultrasonic frequency (unless there is an operation control for varying
this quantity); and type of waveform (continuous wave or amplitude
modulated).
(ii) Generators employing amplitude-modulated waveforms shall also
bear a label that provides the following information: Pulse duration and
pulse repetition rate (unless there are operation controls for varying
these quantities), an illustration of the amplitude-modulated waveform,
and the ratio of the temporal-maximum effective intensity to the
temporal-average effective intensity. (If this ratio is a function of
any operation control setting, then the range of the ratio shall be
specified, and the waveform illustration shall be provided for the
maximum value of this ratio.)
(4) Applicators. Each applicator shall bear a label that provides
the following information:
(i) The brand name, model designation, and unique serial number or
other unique identification so the applicator is individually
identifiable;
(ii) A designation of the generator(s) for which the applicator is
intended; and
(iii) The ultrasonic frequency, effective radiating area, maximum
beam nonuniformity ratio, type of applicator (focusing, collimating,
diverging), and for a focusing applicator the focal length and focal
area.
(5) Label specification. Labels required by this paragraph shall be
permanently affixed to or inscribed on the ultrasonic therapy product;
they shall be legible and clearly visible. If the size, configuration,
or design of the ultrasonic therapy product would preclude compliance
with the requirements of this paragraph, the Director, Center for
Devices and Radiological Health, may approve alternate means of
providing such labels).
(e) Tests for determination of compliance--(1) Tests for
certification. Tests on which certification pursuant to Sec. 1010.2 of
this chapter is based shall account for all measurement errors and
uncertainties. Such tests shall also account
[[Page 636]]
for increases in emission and degradation in radiation safety that occur
with age.
(2) Test conditions. Except as provided in Sec. 1010.13 of this
chapter, tests for compliance with each of the applicable requirements
of this section shall be made:
(i) For all possible combinations of adjustments of the controls
listed in the operation instructions.
(ii) With the ultrasonic radiation emitted into the equivalent of an
infinite medium of distilled, degassed water at 30 deg.C for
measurements concerning the ultrasonic radiation.
(iii) With line voltage variations in the range of
plus-minus10 percent of the rated value specified by the
manufacturer.
(3) Measurement parameters. Measurements for determination of the
spatial distribution of the ultrasonic radiation field shall be made
with a detector having dimensions of less than one wavelength in water
or an equivalent measurement technique.
(f) Informational requirements--(1) Servicing information. The
manufacturer of an ultrasonic therapy product shall provide or cause to
be provided to servicing dealers and distributors, and to others upon
request, at a cost not to exceed the cost of preparation and
distribution adequate instructions for operations, service, and
calibration, including a description of those controls and procedures
that could be used to increase radiation emission levels, and a schedule
of maintenance necessary to keep equipment in compliance with this
section. The instructions shall include adequate safety precautions that
may be necessary regarding ultrasonic radiation exposure.
(2) User information. The manufacturer of an ultrasonic therapy
product shall provide as an integral part of any user instruction or
operation manual that is regularly supplied with the product, or, if not
so supplied, shall cause to be provided with each ultrasonic therapy
product, and to others upon request, at a cost not to exceed the cost of
preparation and distribution:
(i) Adequate instructions concerning assembly, operation, safe use,
any safety procedures and precautions that may be necessary regarding
the use of ultrasonic radiation, and a schedule of maintenance necessary
to keep the equipment in compliance with this section. The operation
instructions shall include a discussion of all operation controls, and
shall describe the effect of each control.
(ii) Adequate description of the spatial distribution of the
ultrasonic radiation field and the orientation of the field with respect
to the applicator. This will include a textual discussion with diagrams,
plots, or photographs representative of the beam pattern. If there is
more than one ultrasonic transducer in an applicator and their positions
are not fixed relative of each other, then the description must specify
the spatial distribution of the ultrasonic radiation field emitted by
each ultrasonic transducer and present adequate examples of the
combination field of the ultrasonic tranducers with regard to safe use.
The description of the ultrasonic radiation field shall state that such
description applies under conditions specified in paragraph (e)(2)(ii)
of this section.
(iii) Adequate description, as appropriate to the product, of the
uncertainties in magnitude expressed in terms of percentage error, of
the ultrasonic frequency effective radiating area, and, where
applicable, the ratio of the temporal-maximum effective intensity to the
temporal-average effective intensity, pulse duration, pulse repetition
rate, focal area, and focal length. The errors in indications specified
in paragraphs (c)(1) and (c)(2) of this section shall be stated in the
instruction manual.
(iv) A listing of controls, adjustments, and procedures for
operation and maintenance, including the warning ``Caution--use of
controls or adjustments or performance of procedures other than those
specified herein may result in hazardous exposure to ultrasonic
energy.''
[43 FR 7166, Feb. 17, 1978, as amended at 45 FR 16483, Mar. 14, 1980; 53
FR 11255, Apr. 6, 1988]
[[Page 637]]