Fluke Biomedical 76-419-4150 - Manual (Page 11)

Operation
§1020.33 Computed Tomography (CT) Equipment
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3) Imaging Performance Information . The following performance data shall be provided for the CT conditions
of operation used to provide the information required by paragraph (c)(2)(i) of this section. All other aspects of
data collection, including the x-ray attenuation properties of the material in the tomographic section, shall be
similar to those used to provide the dose information required by paragraph (c)(2)(i) of this section. For any CT x-
ray system designed to image both the head and body, separate imaging performance information shall be
provided for each application.
(i) A statement of the noise.
(ii) A graphical presentation of the modulation transfer function for the same image processing and display
mode as that used in the statement of the noise.
(iii) A statement of the nominal tomographic section thickness(es).
(iv) A graphical presentation of the sensitivity profile, at the location corresponding to the center location of the
dosimetry phantom, for each selectable nominal tomographic section thickness for which the dose profile is
given according to paragraph (c)(2)(iv) of this section.
(v) A description of the phantom or device and test protocol or procedure used to determine the specifications
and a statement of the maximum deviation from the specifications provided in accordance with paragraphs
(c)(3)(i),(ii),(iii), and (iv) of this section. Deviation of actual values may not exceed these limits.
D. Quality Assurance
The manufacturer of any CT x-ray system shall provide the following with each system. All information required by
this subsection shall be provided in a separate section of the user's instructional manual.
1) A phantom(s) capable of providing an indication of contrast scale, noise, nominal tomographic section
thickness, the spatial resolution capability of the system for low and high contrast objects, and measuring the
mean CT number of water or a reference material.
2) Instructions on the use of the phantom(s) including a schedule of testing appropriate for the system, allowable
variations for the indicated parameters, and a method to store as records, quality assurance data.
3) Representative images obtained with the phantom(s) using the same processing mode and CT conditions of
operation as in paragraph (c)(3) of this section for a properly functioning system of the same model. The
representative images shall be of two forms as follows:
(i) Photographic copies of the images obtained from the image display device
(ii) Images stored in digital form on a storage medium compatible with the CT x-ray system. The CT x-ray
system shall be provided with the means to display these images on the image display device.
E. [Reserved]
F. Control and Indication of Conditions of Operation
1) The CT conditions of operation to be used during a scan or a scan sequence shall be indicated prior to
initiation of a scan or a scan sequence. On equipment having all or some of these conditions of operation at
fixed values, this requirement may be met by permanent markings. Indication of the CT conditions of
operation shall be visible from any position from which scan initiation is possible.
2) Timers , (i) Means shall be provided to terminate the x-ray exposure automatically by either de-energizing the
x-ray source or shuttering the x-ray beam in the event of equipment failure affecting data collection. Such
termination shall occur within an interval that limits the total scan time to no more than 110 percent of its
preset value through the use of either a backup timer or devices which monitor equipment function. A visible
signal shall indicate when the x-ray exposure has been terminated through these means and manual resetting
of the CT conditions of operation shall be required prior to the initiation of another scan.
(ii) Means shall be provided so that the operator can terminate the x-ray exposure at any time during a scan,
or series of scans under x-ray system control, of greater than one-half second duration. Termination of the