| (viii) Film processing.
(I) Films shall be developed in accordance with the
time-temperature relationships recommended by the film manufacturer.
The specified developer temperature for automatic processing and the
time-temperature chart for manual processing shall be posted in the
darkroom. If the registrant determines an alternate time-temperature
relationship is more appropriate for a specific facility, that time-temperature
relationship shall be documented and posted.
(II) Chemicals shall be replaced according to the chemical
manufacturer's or supplier's recommendations or at an interval not
to exceed 3 months.
(III) Darkroom light leak tests shall be performed
and any light leaks corrected at intervals not to exceed 6 months.
(IV) Lighting in the film processing/loading area shall
be maintained with the filter, bulb wattage, and distances recommended
by the film manufacturer for that film emulsion or with products that
provide an equivalent level of protection against fogging.
(V) Corrections or repairs of the light leaks or other
deficiencies in subclauses (II), (III), and (IV) of this clause shall
be initiated within 72 hours of discovery and completed no longer
than 15 days from detection of the deficiency unless a longer time
is authorized by the agency. Records of the correction or repairs
shall include the date and initials of the individual performing these
functions and shall be maintained in accordance with subsection (l)
of this section for inspection by the agency.
(VI) Documentation of the items in subclauses (II),
(III), and (V) of this clause shall be maintained at the site where
performed and shall include the date and initials of the individual
completing these items. These records shall be kept in accordance
with subsection (l) of this section for inspection by the agency.
(ix) Alternative processing systems. Users of daylight
processing systems, laser processors, self-processing film units,
or other alternative processing systems shall follow manufacturer's
recommendations for image processing. Documentation that the registrant
is following manufacturer's recommendations shall include the date
and initials of the individual completing the document and shall be
maintained at the site where performed in accordance with subsection
(l) of this section for inspection by the agency.
(x) Digital imaging acquisition systems. Users of digital
imaging acquisition systems shall follow quality assurance/quality
control protocol for image processing established by the manufacturer
or, if no manufacturer's protocol is available, by the registrant.
The registrant shall include the protocol, whether established by
the registrant or the manufacturer in its operating and safety procedures.
The registrant shall document the frequency at which the quality assurance/quality
control protocol is performed. Documentation shall include the date
and initials of the individual completing the document and shall be
maintained at the site where performed in accordance with subsection
(l) of this section for inspection by the agency.
(B) Additional requirements for radiation therapy simulators
used in the general radiographic mode of operation.
(i) Beam quality (HVL). The half-value layer of the
useful beam for a given x-ray tube potential shall not be less than
the values shown in the following Table IV. If it is necessary to
determine such half-value layer at an x-ray tube potential that is
not listed in Table IV, linear interpolation may be made.
Attached Graphic
(ii) Technique and exposure indicators.
(I) 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 that
are set prior to the exposure shall be indicated.
(II) The indicated technique factors shall be accurate
to within manufacturer's specifications. If these specifications are
not available from the manufacturer, the factors shall be accurate
to within ±10% of the indicated setting.
(iii) Beam limitation.
(I) The beam limiting device (collimator) shall restrict
the useful beam to the area of clinical interest.
(II) A method shall be provided to visually define
the center (cross-hair centering) of the x-ray field to within a 2
mm diameter.
(III) A method shall be provided to accurately indicate
the distance to within 2 mm.
(IV) The delineator wires shall be accurate with the
indicated setting within 2 mm.
(V) The x-ray field shall be congruent with the light
field within 2 mm.
(iv) Timers. Means shall be provided to terminate the
exposure at a preset time interval, a preset product of current and
time, a preset number of pulses, or a preset radiation exposure to
the image receptor. In addition, 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 and a visual and/or audible signal shall
indicate when an exposure has been terminated.
(v) AEC. When an AEC is provided, an indication shall
be made on the control panel when this mode of operation is selected.
(vi) Timer reproducibility. When all technique factors
are held constant, including control panel selections associated with
AEC systems, the coefficient of variation of exposure interval for
both manual and AEC systems shall not exceed 0.05. This requirement
applies to clinically used techniques.
(vii) Exposure reproducibility. When all technique
factors are held constant, including control panel selections associated
with AEC systems, the coefficient of variation of exposure for both
manual and AEC systems shall not exceed 0.05. This requirement applies
to clinically used techniques.
(viii) Linearity.
Attached Graphic
(C) Additional requirements for radiation therapy simulators
utilizing fluoroscopic capabilities.
(i) X-ray production in the fluoroscopic mode shall
be controlled by a device that requires continuous pressure by the
fluoroscopist for the entire time of the exposure (continuous pressure
type switch).
(ii) During fluoroscopy and cinefluorography, the kV
and the mA shall be continuously indicated at the control panel and/or
the fluoroscopist's position.
(iii) The SSD shall not be less than the 20 cm for
image-intensified fluoroscopes used for examinations as specified
in the registrant's operating and safety procedures. The written operating
and safety procedures shall provide precautionary measures to be adhered
to during the use of this device. The procedures shall provide information
on the means to restore the unit to a 30 cm SSD when the unit is returned
to general service.
(iv) Fluoroscopic timers shall meet the following requirements.
(I) Means shall be provided to preset the cumulative
on-time of the fluoroscopic x-ray tube. The maximum cumulative time
of the timing device shall not exceed 5 minutes without resetting.
(II) A signal audible to the fluoroscopist shall indicate
the completion of any preset cumulative on-time. Such signal shall
continue to sound while x-rays are produced until the timing device
is reset. In lieu of such signal, the timer shall terminate the beam
after the preset cumulative on-time is completed.
(v) The exposure foot switch shall be permanently mounted
in the control booth to ensure that the operator cannot enter the
simulator room while the fluoroscope is activated.
(vi) Simulators shall duplicate the geometric conditions
of the radiation therapy equipment plan and therefore measurements
regarding geometric conditions shall be performed in accordance with
subsection (h)(3)(C)(iii)(I) of this section.
(vii) If the treatment-planning system is different
from the treatment-delivery system, the accuracy of electronic transfer
of the treatment-delivery parameters to the treatment-delivery unit
shall be verified at the treatment location.
(D) Additional requirements for radiation therapy simulators
utilizing CT capabilities. CT simulators producing digital images
only are exempt from the requirements of this subparagraph and paragraph
(h)(4)(A)(i), (viii), and (ix) of this subsection.
(i) Equipment requirements.
(I) Tomographic systems shall meet the following requirements.
(-a-) For any single tomogram system, means shall be
provided to permit visual determination of the tomographic plane or
a reference plane offset from the tomographic plane.
(-b-) For any multiple tomogram system, means shall
be provided to permit visual determination of the tomographic plane
or a reference plane offset from the tomographic plane.
Cont'd... |
