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(2) Optional filtration. Fluoroscopic systems (n) Aluminum equivalent of material between nanufactured on or after June 10, 2006, incor- patient and image receptor. Except when used orating an x-ray tube(s) with a continuous in a CT x-ray system, the aluminum equivautput of 1 kilowatt or more and an anode
lent of each of the items listed in table 2 in eat storage capacity of 1 million heat units
paragraph (n) of this section, which are used r more shall provide the option of adding x
between the patient and image receptor, may ay filtration to the diagnostic source as
not exceed the indicated limits. Compliance embly in addition to the amount needed to
shall be determined by X-ray measurements neet the HVL provisions of $1020.30(m)(1). 'he selection of this additional x-ray filtra
made at a potential of 100 kilovolts peak and ion shall be either at the option of the user
with an x-ray beam that has an HVL specir automatic as part of the selected mode of
fied in table 1 in paragraph (m)(1) of this secperation. A means of indicating which com
tion for the potential. This requirement apination of additional filtration is in the x
plies to front panel(s) of cassette holders and ay beam shall be provided.
film changers provided by the manufacturer (3) Measuring compliance. For capacitor en- for patient support or for prevention of forrgy storage equipment, compliance shall be eign object intrusions. It does not apply to etermined with the maximum selectable screens and their associated mechanical supuantity of charge per exposure.
port panels or grids. Table 2 follows: TABLE 2
tem does not result in a failure to comply with $ 1020.31, 1020.32, or 1020.33.
(0) Battery charge indicator. On batteryowered generators, visual means shall be rovided on the control panel to indicate hether the battery is in a state of charge dequate for proper operation. (p) [Reserved] (9) Modification of certified diagnostic I-ray omponents and systems. (1) Diagnostic X-ray omponents and systems certified in accordnce with $ 1010.2 of this chapter shall not be 1odified such that the component or system Lils to comply with any applicable provision [ this chapter unless a variance in accordnce with $ 1010.4 of this chapter or an exmption under section 534(a)(5) or 538(b) of le Federal Food, Drug, and Cosmetic Act us been granted. (2) The owner of a diagnostic x-ray system ho uses the system in a professional or mmercial capacity may modify the sysm, provided the modification does not reut in the failure of the system or compoent to comply with the applicable requireents of this section or of g 1020.31, 1020.32, or 20.33. The owner who causes such modificaon need not submit the reports required by ibpart B of part 1002 of this chapter, proded the owner records the date and the deils of the modification in the system cords and maintains this information, and ovided the modification of the x-ray sys
$1020.31 Radiographic equipment.
The provisions of this section apply to equipment for the recording of images, except equipment involving use of an image intensifier or computed tomography x-ray systems manufactured on or after November 28, 1984.
(a) Control and indication of technique factors—(1) Visual indication. The technique factors to be used during an exposure shall be indicated before the exposure begins, except when automatic exposure controls are used, in which case the technique factors which are set prior to the exposure shall be indicated. On equipment having fixed technique factors, this requirement may be met by permanent markings. Indication of technique factors shall be visible from the operator's position except in the case of spot films made by the fluoroscopist.
(2) Timers. Means shall be provided to terminate the exposure at a preset
(4) Accuracy. Deviation of technique factors from indicated values shall not exceed the limits given in the informa tion provided in accordance with
time interval, a preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor.
(i) Except during serial radiography, the operator shall be able to terminate the exposure at any time during an exposure of greater than one-half second. Except during panoramic dental radiography, termination of exposure shall cause automatic resetting of the timer to its initial setting or to zero. It shall not be possible to make an exposure when the timer is set to a zero or off position if either position is provided.
(ii) During serial radiography, the operator shall be able to terminate the xray exposure(s) at any time, but means may be provided to permit completion of any single exposure of the series in process.
(3) Automatic exposure controls. When an automatic exposure control is provided:
(i) Indication shall be made on the control panel when this mode of operation is selected;
(ii) When the x-ray tube potential is equal to or greater than 51 kilovolts peak (kVp), the minimum exposure time for field emission equipment rated for pulsed operation shall be equal to or less than a time interval equivalent to two pulses and the minimum exposure time for all other equipment shall be equal to or less than 1/60 second or a time interval required to deliver 5 milliamperes-seconds (mAs), whichever is greater;
(iii) Either the product of peak x-ray tube potential, current, and exposure time shall be limited to not more than 60 kilowatt-seconds (kW's) per exposure or the product of x-ray tube current and exposure time shall be limited to not more than 600 mAs per exposure, except when the x-ray tube potential is less than 51 kVp, in which case the product of x-ray tube current and exposure time shall be limited to not more than 2,000 mAs per exposure; and
(iv) A visible signal shall indicate when an exposure has been terminated at the limits described in paragraph (a)(3)(iii) of this section, and manual resetting shall be required before further automatically timed exposures can be made.
(b) Reproducibility. The following requirements shall apply when the equipment is operated on an adequate power supply as specified by the manufacturer in accordance with the requirements of § 1020.30(h)(3);
(1) Coefficient of variation. For any specific combination of selected technique factors, the estimated coefficient of variation of radiation exposures shall be no greater than 0.05.
(2) Measuring compliance. Determination of compliance shall be based on 10 consecutive measurements taken within a time period of 1 hour. Equipment manufactured after September 5, 1978, shall be subject to the additional requirement that all variable controls for technique factors shall be adjusted to alternate settings and reset to the test setting after each measurement. The percent line-voltage regulation shall be determined for each measurement. All values for percent line-voltage regulation shall be within 1 of the mean value for all measurements. For equipment having automatic exposure controls, compliance shall be determined with a sufficient thickness of attenuating material in the useful beam such that the technique factors can be adjusted to provide individual exposures of a minimum of 12 pulses on field emission equipment rated for pulsed operation or no less than one-tenth second per exposure on all other equipment.
(c) Linearity. The following requirements apply when the equipment is operated on a power supply as specified by the manufacturer in accordance with the requirements of g 1020.30(h)(3) for any fixed x-ray tube potential within the range of 40 percent to 100 percent of the maximum rated.
(1) Equipment having independent selection of x-ray tube current (mA). The average ratios of exposure to the indicated milliampere-seconds product (C kg/mAs (or mR/mAs)) obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum. This is: 1X,-X2/0.10(X,+Xz); where X, and X2 are the average C/kg.
S (or mR/
mAs) values obtained at edges of the x-ray field along either the h of two consecutive tube current length or width of the visually defined tings or at two settings differing by field shall not exceed 2 percent of the more than a factor of 2 where the distance from the source to the center e current selection is continuous. of the visually defined field when the %) Equipment having selection of x-ray surface upon which it appears is pere current-exposure time product (mAs). pendicular to the axis of the x-ray
equipment manufactured after y 3, 1994 the average ratios of expo- (ii) When a light localizer is used to e to the indicated milliampere-sec define the x-ray field, it shall provide Is product (C/kg/mAs (or mR/mAs)) an average illuminance of not less than ained at any two consecutive mas 160 lux (15 footcandles) at 100 centiector settings shall not differ by meters or at the maximum SID, whichre than 0.10 times their sum. This is: ever is less. The average illuminance -X2<0.10(X,+X2); where X and X2 shall be based upon measurements the average C/kg/
mAs (or mR/mAs) made in the approximate center of ues obtained at each of two consecu- each quadrant of the light field. Radie mas selector settings or at two ation therapy simulation systems are tings differing by no more than a exempt from this requirement. tor of 2 where the mAs selector pro (iii) The edge of the light field at 100 les continuous selection.
centimeters or at the maximum SID, 3) Measuring compliance. Determina- whichever is less, shall have a contrast in of compliance will be based on 10 ratio, corrected for ambient lighting, posures, made within 1 hour, at of not less than 4 in the case of beamch of the two settings. These two set- limiting devices designed for use on igs may include any two focal spot stationary equipment, and a contrast les except where one is equal to or ratio of not less than 3 in the case of is than 0.45 millimeters and the other beam-limiting devices designed for use greater than 0.45 millimeters. For on mobile and portable equipment. The rposes of this requirement, focal spot contrast ratio is defined as I I2, where le is the focal spot size specified by I, is the illuminance 3 millimeters e x-ray tube manufacturer. The per- from the edge of the light field toward nt line-voltage regulation shall be the center of the field; and 12 is the iltermined for each measurement. All luminance 3 millimeters from the edge lues for percent line-voltage regula of the light field away from the center on at any one combination of tech of the field. Compliance shall be deterque factors shall be within #1 of the mined with a measuring aperture of 1 ean value for all measurements at millimeter. lese technique factors,
(e) Field indication and alignment on (d) Field limitation and alignment for stationary general purpose X-ray equipobile, portable, and stationary general ment. Except when spot-film devices or irpose X-ray systems. Except when special attachments for mammography ot-film devices or special attach are in service, stationary general purents for mammography are in serv- pose x-ray systems shall meet the fole, mobile, portable, and stationary lowing requirements in addition to neral purpose radiographic X-ray sys those prescribed in paragraph (d) of ms shall meet the following require this section: ents:
(1) Means shall be provided to indi(1) Variable X-ray field limitation. A cate when the axis of the x-ray beam is eans for stepless adjustment of the perpendicular to the plane of the image ze of the x-ray field shall be provided. receptor, to align the center of the xach dimension of the minimum field ray field with respect to the center of ze at an SID of 100 centimeters shall the image receptor to within 2 percent
equal to or less than 5 centimeters. of the SID, and to indicate the SID to (2) Visual definition. (i) Means for vis- within 2 percent; illy defining the perimeter of the x (2) The beam-limiting device shall ny field shall be provided. The total numerically indicate the field size in isalignment of the edges of the vis- the plane of the image receptor to ally defined field with the respective which it is adjusted;
(3) Indication of field size dimensions and SID's shall be specified in centimeters and/or inches and shall be such that aperture adjustments result in xray field dimensions in the plane of the image receptor which correspond to those indicated by the beam-limiting device to within 2 percent of the SID when the beam axis is indicated to be perpendicular to the plane of the image receptor; and
(4) Compliance measurements will be made at discrete SID's and image receptor dimensions in common clinical use (such as SID's of 100, 150, and 200 centimeters and/or 36, 40, 48, and 72 inches and nominal image receptor dimensions of 13, 18, 24, 30, 35, 40, and 43 centimeters and/or 5, 7, 8, 9, 10, 11, 12, 14, and 17 inches) or at any other specific dimensions at which the beamlimiting device or its associated diagnostic X-ray system is uniquely designed to operate.
(f) Field limitation on radiographic Xray equipment other than general purpose radiographic systems—(1) Equipment for use with intraoral image receptors. Radiographic equipment designed for use with an intraoral image receptor shall be provided with means to limit the xray beam such that:
(i) If the minimum source-to-skin distance (SSD) is 18 centimeters or more, the x-ray field at the minimum SSD shall be containable in a circle having a diameter of no more than 7 centimeters; and
(ii) If the minimum SSD is less than 18 centimeters, the x-ray field at the minimum SSD shall be containable in a circle having a diameter of no more than 6 centimeters.
(2) X-ray systems designed for one image receptor size. Radiographic equipment designed for only one image receptor size at a fixed SID shall be provided with means to limit the field at the plane of the image receptor to dimensions no greater than those of the image receptor, and to align the center of the x-ray field with the center of the image receptor to within 2 percent of the SID or shall be provided with means to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor.
(3) Systems designed for mammography, (i) Mammographic beam-limiting de vices manufactured after September 30, 1999, shall be provided with means to limit the useful beam such that the xray field at the plane of the image receptor does not extend beyond any edge of the image receptor by more than 2 percent of the SID. This requirement can be met with a system that performs as prescribed in paragraphs (f)(4)(i), (f)(4)(ii), and (f)(4)(iii) of this section. For systems that allow changes in the SID, the SID indication specified in paragraphs (f)(4)(ii) and (f)(4)(iii) of this section shall be the maximum SID for which the beam-limiting device or aperture is designed
(ii) Each image receptor support device intended for installation on a sys tem designed for mammography shall have clear and permanent markings to indicate the maximum image receptor size for which it is designed.
(4) Other I-ray systems. Radiographic systems not specifically covered in paragraphs (d), (e), (f)(2), (f)(3), and (h of this section and systems covered in paragraph (f)(1) of this section, which are also designed for use with extraora! image receptors and when used with an extraoral image receptor, shall be provided with means to limit the X-ray field in the plane of the image receptor so that such field does not exceed each dimension of the image receptor by more than 2 percent of the SID, when the axis of the x-ray beam is perpendicular to the plane of the image receptor. In addition, means shall be provided to align the center of the x-ray field with the center of the image receptor to within 2 percent of the SID. or means shall be provided to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor. These requirements may be met with:
(i) A system which performs in accordance with paragraphs (d) and (e) of this section; or when alignment means are also provided, may be met with either;
(ii) An assortment of removable. fixed-aperture, beam-limiting devices sufficient to meet the requirement for each combination of image receptor
ize and SID for which the unit is de- mined when the equipment indicates igned. Each such device shall have that the beam axis is perpendicular to lear and permanent markings to indi the plane of the image receptor and the ate the image receptor size and SID provisions of paragraph (g)(2) of this or which it is designed; or
section are met. Compliance shall be (iii) A beam-limiting device having determined no sooner than 5 seconds
tiple fixed apertures sufficient to after insertion of the image receptor. neet the requirement for each com
(4) Operator initiated undersizing. The ination of image receptor size and SID
PBL system shall be capable of operor which the unit is designed. Perma
ation such that, at the discretion of lent, clearly legible markings shall in
the operator, the size of the field may licate the image receptor size and SID
be made smaller than the size of the or which each aperture is designed and
image receptor through stepless adjusthall indicate which aperture is in posi
ment of the field size. Each dimension ion for use.
of the minimum field size at an SID of (g) Positive beam limitation (PBL). The
100 centimeters shall be equal to or less equirements of this paragraph shall
than 5 centimeters. Return to PBL apply to radiographic systems which
function as described in paragraph ontain PBL.
(g)(1) of this section shall occur auto(1) Field size. When a PBL system is
matically upon any change of image provided, it shall prevent x-ray produc
receptor size or SID. tion when:
(5) Override of PBL. A capability may (i) Either the length or width of the x-ray field in the plane of the image re
be provided for overriding PBL in case ceptor differs from the corresponding
of system failure and for servicing the image receptor dimension by more
system. This override may be for all
SID's and image receptor sizes. A key than 3 percent of the SID; or (ii) The sum of the length and width
shall be required for any override capadifferences as stated in paragraph
bility that is accessible to the oper(g)(1)(i) of this section without regard
ator. It shall not be possible to remove to sign exceeds 4 percent of the SID.
the key while PBL is overridden. Each (iii) The beam limiting device is at
such key switch or key shall be clearly an SID for which PBL is not designed
and durably labeled as follows: for sizing.
For X-ray Field Limitation System Failure (2) Conditions for PBL. When provided, the PBL system shall function as de
The override capability is considered acscribed in paragraph (g)(1) of this sec
cessible to the operator if it is referenced in
the operator's manual or in other material tion whenever all the following condi
intended for the operator or if its location is tions are met:
such that the operator would consider it part (i) The image receptor is inserted
of the operational controls. into a permanently mounted cassette holder;
(h) Field limitation and alignment for (ii) The image receptor length and
spot-film devices. The following requirewidth are less than 50 centimeters;
ments shall apply to spot-film devices, (iii) The x-ray beam axis is within 73
except when the spot-film device is degrees of vertical and the SID is 90 provided for use with a radiation thercentimeters to 130 centimeters inclu- apy simulation system: sive; or the x-ray beam axis is within (1) Means shall be provided between 23 degrees of horizontal and the SID is the source and the patient for adjust90 centimeters to 205 centimeters inclu ment of the x-ray field size in the plane sive;
of the image receptor to the size of (iv) The x-ray beam axis is perpen that portion of the image receptor dicular to the plane of the image recep- which has been selected on the spottor to within +3 degrees; and
film selector. Such adjustment shall be (v) Neither tomographic nor stereo accomplished automatically when the scopic radiography is being performed. X-ray field size in the plane of the
(3) Measuring compliance. Compliance image receptor is greater than the sewith the requirements of paragraph lected portion of the image receptor. If (g)(1) of this section shall be deter- the x-ray field size is less than the size