FDA 3627 CT X-Ray

Form Approved: OMB No. 0910-0025
Expiration Date: October 31, 2013

FORM FDA 3627 (11/10)
A Guide for the Submission of Initial Reports
on Computed Tomography X-Ray Systems

Public reporting burden for this collection of information is estimated to average 24 hours per
response, including the time for reviewing instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the collection of information. Send comments
regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to:
Department of Health and Human Services
Food and Drug Administration
Office of Chief Information Officer
1350 Piccard Drive, Room 400
Rockville, MD 20850
An agency may not conduct or sponsor, and a person is not required to respond to, a collection
of information unless it displays a currently valid OMB control number.

This guidance was written prior to the February 27, 1997 implementation of FDA’s
Good Guidance Practices, GGP’s. It does not create or confer rights for or on any person
and does not operate to bind FDA or the public. An alternative approach may be used if
such approach satisfies the requirements of the applicable statute, regulations, or both.
This guidance will be updated in the next revision to include the standard elements of GGP’s.

More industry guidance and assistance can be found at the FDA homepage, see:
http://www.fda.gov/Radiation-EmittingProducts/ .

Send your completed report to:
CENTER FOR DEVICES AND RADIOLOGICAL HEALTH
DOCUMENT MAIL CENTER – WO66-G609
ATTN: ELECTRONIC PRODUCT REPORTS
10903 NEW HAMPSHIRE AVENUE
SILVER SPRING, MD 20993-0002
Questions about reporting and suggestions for changes to this guide may be sent to the above
address or may be discussed by calling (301) 796-5710.

FORM FDA 3627 (11/10)

A GUIDE FOR THE SUBMISSION OF INITIAL REPORTS
ON COMPUTED TOMOGRAPHY X-RAY SYSTEMS

PUBLISHED BY:
DIVISION OF STANDARDS ENFORCEMENT
X-RAY PRODUCTS BRANCH

DECEMBER 1985

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
FOOD AND DRUG ADMINISTRATION
CENTER FOR DEVICES AND RADIOLOGICAL HEALTH
SILVER SPRING, MD 20993

FORM FDA 3627 (11/10)

This page is deliberately blank.

FORM FDA 3627 (11/10)

PAGE
CONTENTS
INTRODUCTION

ii

DEFINITIONS

iii

PART 100 - IDENTIFICATION

1

Section 101.0 - Report Identification
Section 102.0 - Product Identification
Section 103.0 - Labeling/Information

1
1
6

PART 200 - SYSTEM DESCRIPTION ...........

7

Section 201.0 - Control & Indication of the CT Conditions of
Operation - Visual Indication
Section 202.0 - Control & Indication of the CT Conditions
of Operation - Timers
Section 203.0 - Tomographic Plane Indication & Alignment
Section 204.0 - Beam On and Shutter Status Indicators
Section 205.0 - CT Number Mean & Standard Deviation
Section 206.0 - Labeling

7
7
8
8
8
9

PART 300 - QUALITY CONTROL

10

Section 301.0 - Leakage Radiation From the Diagnostic
Source Assembly
Section 302.0 - Beam Quality
Section 303.0 - Peak Tube Potential
Section 304.0 - Tube Current
Section 305.0 - Scan Time
Section 306.0 - Tube Current - Exposure Time Product
Section 307.0 - CTDI/Dose Profile Information
Section 308.0 - Imaging Performance
Section 309.0 - Equipment Failure Exposure Termination ....
Section 310.0 - Tomographic Plane Location
Section 311.0 - Illumination Levels of the Light Source ...
Section 312.0 - Shutter Leakage Radiation
Section 313.0 - Scan Increment Accuracy

10
10
11
11
12
12
12
13
14
14
15
15
16

Attachment A

17

PART 400 - COMMON ASPECTS ...

19

Section 401.0 - Instrumentation .........
Section 402.0 - Sampling ................

19
20
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FORM FDA 3627 (11/10)

A GUIDE FOR THE SUBMISSION OF INITIAL REPORTS ON COMPUTED
TOMOGRAPHY
X-RAY SYSTEMS
INTRODUCTION
This guide outlines for a manufacturer, a format for the presentation of initial and
supplemental reports on computed tomography (CT) x-ray systems which are subject to the
Performance Standard 21 CFR 1020.30 and 1020.33.
The subject reporting guide is an attempt to identify the pertinent information needed
by the Center for Devices and Radiological Health (the Center) under the Radiation Control
for Health and Safety Act of 1968 (P.L. 90-602). The identification of this information will
make the manufacturer’s reporting task somewhat easier since, after the initial
organization of the material, the manufacturer will not be obligated to prepare and submit
such voluminous reports as in the past.
This new guide asks for information in four parts. PART 100 IDENTIFICATION,
containing three sections, asks for information with regard to identification, labeling, and
user’s information. PART 200 - SYSTEM DESCRIPTION, containing five sections, asks for
information pertaining to specific performance characteristics of the equipment.
Manufacturers must answer all questions in this section, as they relate to their systems.
PART 300 - QUALITY CONTROL, containing thirteen sections, asks for presentations of
prototype, production, and assembler test methods and results. PART 400 - COMMON
ASPECTS, containing two sections, asks for test instrument specifications and sampling
protocols. The manufacturer must answer all applicable questions of sections 401.0
and 402.0.
Manufacturers are encouraged to submit a “Common Aspects Report” in order to
simplify their reporting obligations. The Common Aspects Report is a separate initial
report that incorporates a description of test methods, instrumentation, and sampling plans
common to several models. This Common Aspects Report is not intended as a means for
certification of any specific model. Currently, separate initial reports from the same
manufacturer often provide identical descriptions of the quality control program. Such
duplication is costly and entails extra effort for both the manufacturer and the Center. By
development of a Common Aspects Report, standardized test methods, instrumentation,
and sampling plans may be collected into one report. Initial reports for specific models can
reference applicable sections of the Common Aspects Report.
All material shall be submitted in the English language or with an accurate attached
English translation. Definitions for technical terms used in this guide may be found on page
iii.

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FORM FDA 3627 (11/10)

DEFINITIONS
As used in this guide and 21 CFR 1020.30 and 1020.33, the following definitions apply:
(1)

“Assembler” means any person engaged in the business of assembling, replacing, or
installing one or more components into an x-ray system or subsystem.

(2)

“Beam-limiting device” means a device which provides a means to restrict the dimensions
of the x-ray field.

(3)

“Computed tomography dose index (CTDI) means the integral of the dose profile along a
line perpendicular to the tomographic plane divided by the product of the nominal
tomographic section thickness and the number of tomograms produced in a single scan.
This is:
+7T
CTDI = 1/nT ∫ D(z)dz
-7T
Where:
z

= Position along a line perpendicular to the tomographic plane.

D(z)

= Dose at position z.

T

= Nominal tomographic section thickness.

n

= Number of tomograms produced in a single scan.

This definition assumes that for a multiple tomogram system the scan increment
between adjacent scans is nT.
(4)

“Contrast scale” means the change in linear attenuation coefficient per CT number
relative to water; that is:

Contrast scale =

µ x – µw
(CT)X – (CT)W

Where:
µW= Linear attenuation coefficient of water.
µX = Linear attenuation coefficient of material of interest.
(CT)W = CT number of water.
(CT)X = CT number of material of interest.

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FORM FDA 3627 (11/10)

(5)

“Control panel” means that part of the x-ray control upon which are mounted the switches,
knobs, pushbuttons, and other hardware necessary for manually setting the technique
factors.

(6)

“Cooling curve” means the graphical relationship between heat units stored and cooling
time.

(7)

“CT conditions of operation” means all selectable parameters governing the operation of a
CT system including nominal tomographic section thickness, filtration, and the technique
factors as defined in Section 1020.30(b)(36).

(8)

“CT number” means the number used to represent the x-ray attenuation associated with
each elemental area of the CT image.

(9)

“CT dosimetry phantom” means the phantom used for determination of the dose delivered
by a computed tomography system. The phantom shall be a right circular cylinder of
polymethylmethacrylate of density 1.19 +_ 0.01 grams per cubic centimeter. The phantom
shall be at least 14 centimeters in length and shall have diameters of 32.0 centimeters for
testing any CT system designed to image any section of the body (whole body scanners)
and 16.0 centimeters for any system designed to image the head (head scanners) or for
any whole body scanner operated in the head scanning mode. The phantom shall provide
means for the placement of a dosimeter(s) along its axis of rotation and along a line
parallel to the axis of rotation 1.0 centimeter from the outer surface and within the
phantom. Means for the placement of a dosimeter(s) or alignment device at other locations
may be provided for convenience. The means used for placement of a dosimeter(s) (i.e.,
hole size) and the type of dosimeter(s) used is at the discretion of the manufacturer. Any
effect on the doses measured due to the removal of phantom material to accommodate
dosimeters shall be accounted for through appropriate corrections to the reported data or
included in the statement of maximum deviation for the values obtained using the
phantom.

(10)

“Diagnostic source assembly” means the tube housing assembly with a beam-limiting
device attached.

(11)

“Diagnostic x-ray system” means an x-ray system designed for irradiation of any part of
the human body for the purpose of diagnosis or visualization.

(12)

“Dose profile” means the dose as a function of position along a line.

(13)

“Equipment” means x-ray equipment.

(14)

“Exposure” means the quotient of dQ by dm where dQ is the absolute value of the total
charge of the ions of one sign produced in air when all the electrons (negatrons and
positrons) liberated by photons in a volume element of air having mass dm are completely
stopped in air.
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FORM FDA 3627 (11/10)

(15) “Half-value layer, HVL” means the thickness of specified material which attenuates the
beam of radiation to an extent such that the exposure rate is reduced to one-half of its
original value. In this definition the contribution of all scattered radiation, other than any
which might be present initially in the beam concerned, is deemed to be excluded.
(16) “Image receptor” means any device, such as a fluorescent screen or radiographic film or
detector array which transforms incident x-ray photons either into a visible image or into
another form which can be made into a visible image by further transformations.
(17) “Leakage radiation” means radiation emanating from the diagnostic source assembly
except for:
(i) The useful beam and
(ii) radiation produced when the exposure switch or timer is not activated.
(18) “Leakage technique factors” means the technique factors associated with the tube housing
assembly which are used in measuring leakage radiation. They are defined as follows:
(i) For tube housing assemblies intended for capacitor energy storage equipment,
the maximum-rated peak tube potential and the maximum-rated number of
exposures in an hour for operation at the maximum-rated peak tube potential with
the quantity of charge per exposure being 10 millicoulombs (mAs) or the
minimum obtainable from the unit, whichever is larger.
(ii) For tube housing assemblies intended for field emission equipment rated for pulsed
operation, the maximum-rated peak tube potential and the maximum-rated
number of x-ray pulses in an hour for operation at the maximum-rated peak tube
potential.
(iii) For all other tube housing assemblies, the maximum-rated peak tube potential and
the maximum-rated continuous tube current for the maximum-rated peak tube
potential.
(19) “Line-voltage regulation” means the difference between the no-load and the load line
potentials expressed as a percent of the load line potential; that is,
Percent line-voltage regulation = 100(Vn - Vi )Vi
Where:
Vn = No-load line potential and
Vi = Load line potential.
(20) “Maximum line current” means the rms current in the supply line of an x-ray machine
operating at its maximum rating.
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FORM FDA 3627 (11/10)

(21)

“Modulation transfer function” means the modulus of the Fourier transform of the impulse
response of the system.

(22)

“Multiple tomogram system” means a computed tomography system which obtains x-raytransmission data simultaneously during a single scan to produce more than one
tomogram.

(23)

“Noise” means the standard deviation of the fluctuations in CT number expressed as a
percent of the attenuation coefficient of water. Its estimate (Sn) is calculated using the
following expression:
Sn = 100 x CS x s
W
Where:
CS = Contrast scale.
W = Linear attenuation coefficient of water.
s = Estimated standard deviation of the CT numbers of picture elements in a specified
area of the CT image.

(24)

“Nominal tomographic section thickness” means the full-width at half-maximum of the
sensitivity profile taken at the center of the cross-sectional volume over which x-ray
transmission data are collected.

(25)

“Peak tube potential” means the maximum value of the potential difference across the
x-ray tube during an exposure.

(26)

“Picture element" means an elemental area of a tomogram.

(27)

“Rated line voltage” means the range of potentials, in volts, of the supply line specified by
the manufacturer at which the x-ray machine is designed to operate.

(28)

“Rated output current” means the maximum allowable load current of the x-ray
high-voltage generator.

(29)

“Rated output voltage” means the allowable peak potential, in volts, at the output terminals
of the x-ray high-voltage generator.

(30)

“Rating" means the operating limits specified by the manufacturer.

(31)

“Recording” means producing a permanent form of an image resulting from x-ray photons
(e.g., film, videotape).

(32)

“Response time” means the time required for an instrument system to reach 90 percent
of its final reading when the radiation-sensitive volume of the instrument system is
exposed to a step change in radiation flux from zero sufficient to provide a steady state
midscale reading.
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FORM FDA 3627 (11/10)

(33)

“Scan increment” means the amount of relative displacement of the patient with respect to
the CT x-ray system between successive scans measured along the direction of such
displacement.

(34)

“Scan sequence” means a preselected set of two or more scans performed consecutively
underpreselected CT conditions of operation.

(35)

“Sensitivity profile” means the relative response of the CT system as a function of position
along a line perpendicular to the tomographic plane.

(36)

“Single tomogram system” means a CT system which obtains x-ray transmission data
during a scan to produce a single tomogram.

(37)

“Source” means the focal spot of the x-ray tube.

(38)

“Source-image receptor distance (SID)” means the distance from the source to the center
of the input surface of the image receptor.

(39)

“Stationary equipment” means equipment which is installed in a fixed location.

(40)

“Tomogram” means the result of imaging a particular body section or slice.

(41)

“Tomographic plane” means that geometric plane which the manufacturer identifies as
corresponding to the output tomogram.

(42)

“Tomographic section” means the volume of an object whose x-ray attenuation properties
are imaged in a tomogram.

(43)

“Tube” means an x-ray tube, unless otherwise specified.

(44)

“Tube housing assembly” means the tube housing with tube installed. It includes
high-voltage and/or filament transformers and other appropriate elements when they are
contained within the tube housing.

(45)

“Tube rating chart” means the set of curves which specify the rated limits of operation of
the tube in terms of the technique factors.

(46)

“Useful beam” means the radiation which passes through the tube housing port and the
aperture of the beam-limiting device when the exposure switch or timer is activated.

(47)

“Variable-aperture beam-limiting device” means a beam-limiting device which has capacity
for stepless adjustment of the x-ray field size at a given SID.

(48)

“Visible area” means that portion of the input surface of the image receptor over which
incident x-ray photons are producing a visible image.

(49)

“X-ray control” means a device which controls input power to the x-ray high-voltage
generator and/or the x-ray tube. It includes equipment such as timers, phototimers,
automatic brightness stabilizers, and similar devices, which control the technique factors
of an x-ray exposure.
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FORM FDA 3627 (11/10)

(50)

“X-ray equipment” means an x-ray system, subsystem, or component thereof.

(51)

“X-ray field” means that area of the intersection of the useful beam and any one of the set
of planes parallel to and including the plane of the image receptor, whose perimeter is the
locus of points at which the exposure rate is one-fourth of the maximum in the intersection.

(52)

“X-ray high-voltage generator” means a device which transforms electrical energy from the
potential supplied by the x-ray control to the tube operating potential. The device may also
include means for transforming alternating current to direct current, filament transformers
for the x-ray tube(s), high-voltage switches, electrical protective devices, and other
appropriate elements.

(53)

“X-ray system” means an assemblage of components for the controlled production of X
rays. It includes minimally an x-ray high-voltage generator, an x-ray control, a tube housing
assembly, a beam-limiting device, and the necessary supporting structures. Additional
components which function with the system are considered integral parts of the system.

(54)

“X-ray tube” means any electron tube which is designed for the conversion of electrical
energy into x-ray energy.

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FORM FDA 3627 (11/10)

PART 100 - IDENTIFICATION
101.0 REPORT IDENTIFICATION
Please confirm that this report is submitted pursuant to section 1002.10. State each of
the following:
Report type (initial or supplement)
CDRH Accession Number
Name of Manufacturer
Name of Submitter
Corresponding Official
102.0 PRODUCT IDENTIFICATION
102.1 Give the designation of the system being certified in this report:
System Designation:
Head and/or Body Scanner:
Identify each certifiable component that is included in the system. Include component
type, model designation, and manufacturer (certifiable component types: tube housing
assemblies, x-ray controls, x-ray high voltage generators, tables, beam-limiting devices,
and gantries).
Certifiable Component Type

Note:

Model Designation

The gantry certification label serves as the system certification.
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FORM FDA 3627 (11/10)

Manufacturer

102.2 Identify any of the components listed in part 102.1 that you are
certifying in this report.
Certifiable Component Type

Model Designation

103.0 LABELING/INFORMATION
Information requested under this section should be supplied in the appropriate appendix.
Provide an explanation for information that is unavailable or not applicable.
103.1 Provide, in Appendix A, copies of the following labels along with a photograph or drawing
of each certifiable component and/or system showing the location of the attached label.
The standard requires that labels be permanently affixed, legible, and accessible to
view. In the case of beam-limiting devices and tube housing assemblies contained
within the gantry, the identification and certification labels shall be mounted on the
component even though the component is not visible.
The gantry certification shall serve as the certifying label for the entire CT system. In
addition, the date of manufacture as indicated on the gantry label shall serve as the
manufacturing date for the entire CT system.
Appendix

Content

21 CFR Reference

A

1. Certification Labels
2. Identification Labels
3. Warning Labels

1010.2
1010.3
1020.30(j)

103.2 Provide, in Appendix B, a copy of the assembler information requested below. Indicate
the exact page number where this information may be found.

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FORM FDA 3627 (11/10)

Information Requested

21 CFR Reference

1. Assembly & test instructions
to assure compliance

1020.30(g)

2. Compatibility specifications

1020.30(g)

3. Tube reloading instructions

1020.30(e)

103.3

Provide a copy of the users’ information listed below. Provide the exact page number of
the location of each item within each appendix. All users’ information listed below shall be
identified and provided in a separate section of the users, instruction manual or in a
separate manual devoted only to this information.

Appendix
C

Page Number

Content

21 CFR Reference

1. X-ray safety & maintenance schedule

1020.33(h)(1)

2. Tube housing assembly
information

1020.33(h)(2)

3. X-ray control and
generator information

1020.33(h)(3)

4. Beam-limiting device
information

1020.33(h)(4)

5. Reference plane
alignment directions

1020.33(g)(2)

6. Offset plane alignment
directions

1020.33(g)(4)

7. Instructions concerning the use of
the method provided for calculation
of the CT number mean
and standard deviation

1020.33(j)(2)

8. Operating instructions

1020.30(h)

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FORM FDA 3627 (11/10)

Page Number

Appendix
D

Content

21 CFR Reference

1. A statement of the CT
conditions of operation
used to provide the dose
information requested in
parts 2 and 3 below and in
Appendix E, part 5

1020.33(c)(1)

2. Dose Information

1020.33(c)(2)

a.

Page Number

CTDI along the axis of rotation of the phantom and along lines
parallel to the axis of rotation and 1.0 centimeter interior to the
surface of the phantom and 90 0 apart. One of the surface
positions shall be the maximum CTDI obtainable at the 1.0
centimeter depth. The CT conditions of operation (e.g., kVp, mAs,
slice thickness, scan diameter, etc.) shall be the typical values.
The location of the phantom position where the surface (1 cm
interior) CTDI is maximum shall be indicated with respect to the
CT system.

b. CTDI in the center location of the phantom for each selectable CT
condition of operation that varies either the rate or duration of the
exposure. Each condition of operation shall be presented as
normalized to the value in (a) above with the other conditions of
operation the same as in (a). If more than three selections for a
condition of operation are available, the normalized values shall be
given for the maximum, minimum, and an intermediate selection.
c. CTDI at the location of the maximum CTDI at 1.0 centimeter
interior to the surface of the phantom for each selectable peak tube
potential. If more than three selections are available, the
normalized values shall be given for the maximum, minimum, and
an intermediate selection.
d.

Dose profile in the center location of the dosimetry phantom for
each selectable nominal tomographic section thickness. If more
than three selections of section thickness are available, the
normalized values shall be given for the maximum, minimum, and
an intermediate thickness. The dose profile shall be on the same
graph and to the same scale as the corresponding sensitivity
profile.
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FORM FDA 3627 (11/10)

e. A statement of the accuracy of the values given in a through
d above.
3. Imaging performance
1020.33(c)93)
information
a. A statement of the noise
b. A graphical presentation of the modulation transfer function
for the same imaging processing & presentation mode as
that used in the statement of the noise
c. A statement of the nominal tomographic section
thickness(es)
d. A graphical presentation of the sensitivity profile, as
measured in the center of the dosimetry phantom for the
selectable nominal tomographic section thickness for which
the dose profiles are given. This shall be presented on the
same graph and to the same scale as the corresponding
dose profiles. The nominal section thickness shall be defined
as the distance between the 50% sensitivity points on the
sensitivity curve.
e. 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
for items (a-d) above
E

Quality assurance
instructions*

1020.33(d)

1. Phantom description
2. Instructions on phantom use and
schedule for use
3. Listing of allowable variations
for the indicated parameters
4. Description of the method to store
quality assurance data

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5. Representative images obtained or a description of the means used to store
and display such images

*QA tests for noise, contrast scale, nominal tomographic section thickness,
and mean CT number should be done through the data acquisition stage.
Resolution tests of either high or low contrast objects should be done from
measurements through the data acquisition and display stages. The OA tests
on resolution could be performed as two independent tests, i.e., one test
operating on the digital data and one test operating on the display device. The
test for contrast scale should include materials with CT numbers close to
water so that they are representative of the CT number scale of interest to the
user. At least two materials different from water should be used, one with a CT
number approximately plus 100-300 and the other with a CT number of minus
100-300.

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PART 200 - SYSTEM DESCRIPTION
For each section listed below, give a complete description of the means provided to satisfy the
requirement.
201.0

CONTROL AND INDICATION OF THE CT CONDITIONS OF OPERATION -VISUAL
INDICATION

201.1

All CT conditions of operation must be displayed prior to the initiation of each scan or scan
sequence (1020.33(f)(1)). Along with a description of the means provided, you should
include a drawing or picture of the preindicators of technique factors to the operator.

201.2

The displayed conditions of operation must be visible from any position from which scan
initiation is possible (1020.33(f)(1)). Provide a drawing or picture that illustrates the
proximity of any exposure switch to the preindicated technique factors.

202.0

CONTROL AND INDICATION OF THE CT CONDITIONS OF OPERATION - TIMERS

202.1

In the event of equipment failure, means must be provided to automatically limit the total
scan time to no more than 110% of its preset value (1020.33(f)(2)(i)). Give a complete
description of the backup safety device which is provided for this requirement.

202.2

Visual indication must be provided to identify scans terminated through these means
(1020.33(f)(2)(i)). In addition to a description of the means provided, you should include a
picture or drawing of the visible signal that indicates when an exposure has been
terminated by the backup safety device.

202.3

Means must be provided for the manual resetting of the conditions of operation, in the
event of equipment failure, prior to the initiation of another scan (1020.33(f)(2)(i)). Describe
the manual resetting procedures.

202.4

Means must be provided such that the exposure from the system does not exceed the
radiation levels specified in paragraph 1020-30(k) except when x-ray transmission data are
being collected for use in image production or technique factor selection (1020.33(f)(2)(ii)).
Give a description of your design which will limit the dose to the patient to only those
circumstances stated above.

202.5

Means must be provided for the operator to terminate the x-ray exposure at any time during
a scan, or series of scans of greater than 0.5 second duration (1020.33(f)(2)(iii)).
Describe this method.

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202.6

Termination of the x-ray exposure, by the operator, must require manual resetting of the
conditions of operation prior to initiation of another scan (1020.33(f)(2)(iii)). Describe the
manual resetting procedure.

203.0

TOMOGRAPHIC PLANE INDICATION & ALIGNMENT

203.1

For any single tomogram system, means shall be provided to permit visual
determination of the tomographic plane or an offset reference plane (1020.33(g)(1)).
Describe the specific means utilized for indication of location on the patient where the
tomogram will be obtained.

203.2

For any multiple tomogram system, means must be provided to permit visual
determination of the location of a reference plane (1020.33(g)(2)). For multiple
tomogram systems, describe the relationship of the reference plane alignment to the
actual position of the tomograms.

204.0

BEAM ON & SHUTTER STATUS INDICATORS

204.1

Means shall be provided on the x-ray control and on or near the housing of the scanning
mechanism to provide visual indication when and only when X rays are produced
(1020.33(h)(1)). In addition to a description of this means, provide a drawing or picture
to show visual indicators.

204.2

If applicable, means shall be provided on the x-ray control and on or near the housing of
the scanning mechanism to provide visual indication of whether the shutter is open or
closed (1020.33(h)(1)). In addition to a description of this means, provide a drawing or
picture to show the visual indicators.

204.3

The minimum period for x-ray on indication must be 0.5 second or greater
(1020.33(h)(1)). Describe the means provided to meet this requirement.

204.4

Visual indicators (indicating x-ray production and shutter status) on or near the housing
of the scanning mechanism shall be discernible from any point external to the patient
opening, where insertion of any part of the human body into the primary beam is
possible (1020.33(h)(1)). In addition to the description of this means, provide a drawing
or picture that illustrates the location of all indicators at or near the housing of the
scanning mechanism, in relation to the patient opening.

205.0

CT NUMBER MEAN & STANDARD DEVIATION

205.1

Means must be provided for the user to calculate the mean and standard deviation of
CT numbers for an array of picture elements about any location in the image
(1020.33(j)(1)). Describe this means.

205.2

The number of elements in this array must be under user control (1020.33(j)(1)).
Describe the means provided to the user for varying the number of elements in the
array.
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206.0

LABELING

206.1

The warning label must be legible and clearly visible on the control panel containing the
main power switch (1020.30(j)).

206.2

The identification label must contain the name & address of the manufacturer (or the
individual or company under whose name it was sold), the place of manufacture, & the
model designation and serial number (1010.3(a)(1)(2)).

206.3

The month and year of manufacture must be provided clearly & legibly without
abbreviation, and with the year shown as a four-digit number follows: manufactured:
(insert month and year of manufacture) (1010.3(a)(2)(ii)).

206.4

If the place of manufacture as stated on the identification label is coded, please provide
that code (1010.3(a)(2)(i)).

9
FORM FDA 3627 (11/10)

PART 300 - QUALITY CONTROL
For each applicable test listed below, verify that the testing adequately reflects the
critical parameters and addresses the “worst case” conditions. As a result of inherent
inaccuracies of the test methods and instrumentation, rejection limits for any test must
be sufficiently restrictive to account for these inaccuracies.
301.0

LEAKAGE RADIATION FROM THE DIAGNOSTIC SOURCE ASSEMBLY

301.1

Requirement
The leakage radiation from the diagnostic source assembly measured at distance of 1
meter in any direction from the source shall not exceed 100 milliroentgens in 1 hour
when the x-ray tube is operated at its leakage technique factors. Compliance shall be
determined by measurements averaged over an area of 100 square centimeters with no
linear dimension greater than 20 centimeters (1020.30(k)).

301.2

Critical Parameters and “Worst Case” Conditions
a.

The test results must include data representative of each compatible combination
of tube housing assembly, beam-limiting device, and gantry.

b.

To assure the use of maximum rated peak tube potential and continuous tube
current, the test method(s) must provide the procedure for periodic calibration of
technique factors.

c.

For any test using a scan of the diagnostic source assembly, the rate of scan
specified in the test method(s) must account for the response time of the
radiation instrumentation.

d.

Please note and describe any critical parameters and “worst case” conditions
which are unique to your system or test method.

301.3 - 301.5 Provide information as outlined in Attachment A.
302.0

BEAM QUALITY

302.1

Requirement
The half-value layer of the useful beam for a given x-ray tube potential shall not be less
than the values shown in Table I of the diagnostic x-ray standard (see 1020.30(m)).

302.2

Critical Parameters and “Worst Case” Conditions
a.

The test results must include data representative of each compatible combination
of tube housing assembly and beam-limiting device.

b.

Since the peak tube potential has a critical effect on determining the half-value
layer, the test method(s) must provide the procedure for periodic calibration of
tube potential.
10

FORM FDA 3627 (11/10)

c.

d.

To minimize the effect of scatter radiation, the x-ray field specified in the test
method(s) must be just large enough to cover the sensitive volume of the
detector.
Please note and describe any critical parameters and "worst case" conditions
which are unique to your system or test method.

302.3- 302.5 Provide information as outlined in Attachment A.
303.0

PEAK TUBE POTENTIAL

303.1

Requirement
The manufacturer shall state the maximum deviation of the peak tube potential from its
preindicated value during an exposure when the equipment is connected to an adequate
power supply as specified by the manufacturer. The deviation of the peak tube potential
shall not exceed the limits given (see 1020.30(h)(3)(vi)).

303.2

Critical Parameters and “Worst Case” Conditions
a.

To assure compliance with the maximum deviation statements provided to the
user, the test results must include data for “worst case” combinations of
technique factors and supply line conditions (e.g., highest kW, minimum, and
maximum allowable line-voltage regulation).

b.

Please note and describe any critical parameters and “worst case” conditions
which are unique to your system or test method.

303.3 - 303.5 Provide information as outlined in Attachment A.
304.0

TUBE CURRENT

304.1

Requirement
The manufacturer shall state the maximum deviation of the tube current from its
preindicated value during an exposure, when the equipment is connected to an
adequate power supply as specified by the manufacturer. The deviation of the tube
current shall not exceed the limits given (see 1020.30(h)(3)(vi)).

304.2

Critical Parameters and “Worst Case” Conditions
a.

To assure compliance with the maximum deviation statements provided to the
user, the test results must include data for “worst case” combinations of
technique factors and supply line conditions (e.g., highest kW, minimum, and
maximum allowable line-voltage regulation).

b.

Please note and describe any critical parameters and “worst case” conditions
which are unique to your system or test method.

304.3 - 304.5 Provide information as outlined in Attachment A.
11
FORM FDA 3627 (11/10)

305.0

SCAN TIME

305.1

Requirement
The manufacturer shall state the maximum deviation of the scan time from its
preindicated value during an exposure, when the equipment is connected to an
adequate power supply as specified by the manufacturer. The deviation of scan time
shall not exceed the limits given (see 1020.30(h)(3)(vi)).

305.2

Critical Parameters and “Worst Case” Conditions
a.

To assure compliance with the maximum deviation statements provided to the
user, the test results must include data for “worst case” combinations of
technique factors and supply line conditions (e.g., highest kW, minimum and
maximum allowable line-voltage regulation).

b.

Please note and describe any critical parameters and “worst case” conditions
which are unique to your system or test method.

305.3- 305.5 Provide information as outlined in Attachment A.
306.0

TUBE CURRENT - EXPOSURE TIME PRODUCT

306.1

Requirement
The manufacturer shall state the maximum deviation of the tube current exposure time
product (mAs) from its preindicated value during an exposure, when the equipment is
connected to an adequate power supply as specified by the manufacturer. The deviation
of the tube current exposure time product shall not exceed the limits given (see
1020.30(h)(3)(vi)).

306.2

Critical Parameters and “worst case” Conditions
a.

To assure compliance with the maximum deviation statements provided to the
user, the test results must include data for “worst case” combinations of
technique factors and supply line conditions (e.g., highest kW, minimum and
maximum allowable line-voltage regulation).

b.

Please note and describe any critical parameters and “worst case’, conditions
which are unique to your system or test method.

306.3 - 306.5 Provide information as outlined in Attachment A.
307.0

CTDI/DOSE PROFILE INFORMATION
Indicate for each modality, e.g., head, body, or spine procedure:
a.

A statement of the typical scan technique factors (e.g., kVp, mAs, pulse width,
time, etc.)

b.

A statement of the scan diameter.

c.

A statement of the system slice thicknesses.
12

FORM FDA 3627 (11/10)

d.

A statement of the accuracy of the parameters indicated above.

e.

A statement indicating whether the maximum CTDI is obtained from integration of
the dose profile for a single scan or from a direct measurement of the average
dose in an interval equal to the slice thickness at the center of a series of 14
scans that are spaced by the nominal tomographic slice thickness.

f.
307.1

A statement of accuracy of the exposure measurement.

Requirement
The manufacturer shall state the maximum deviation of the dose values given to the
user in accordance with sections 1020.33(c)(2)(i), (ii), (iii), and (iv). The deviation
from these values shall not exceed the limits given (1020.33(c)(2)(v)).

307.2

Critical Parameters and "Worst Case" Conditions
a.

All dose measurements must be performed with the CT dosimetry phantom
placed on the patient couch or support device without additional attenuating
materials present.

b.

The CT conditions of operation for obtaining the CTDI at the five specified
locations shall correspond to typical values (e.g., kVp, mAs, scan diameter slice
thickness) suggested by the manufacturer for CT of the head, body, or spine as
may be appropriate.

c.

The normalized CTDI values must be at least the minimum, maximum mid-range
values for the condition of operation or the values available with the other
conditions of operation set at the typical values.

d.

Please note any assumptions made in or limitations of your test methods in
determining the dose values for your system.

307.3- 307.5 Provide information as outlined in Attachment A.
308.0

IMAGING PERFORMANCE

308.1

Requirement
The manufacturer shall state the maximum deviation from the specifications regarding
imaging performance provided in accordance with section 1020.33(c)(3)(i), (ii), (iii), and
(iv). The deviation from these values shall not exceed the limits given (1020.33(c)(3)(v)).
Questions in this section should be answered as they relate to each of the items listed
in the specified paragraphs of 1020.33(c)(3).

308.2

Critical Parameters and “Worst Case” Conditions
a.

The CT conditions of operation shall correspond to those in (1020.33(c)(2)(i), the
typical conditions of operation suggested by the manufacturer for CT of the head,
body, or spine as may appropriate.
13

FORM FDA 3627 (11/10)

b.

All 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 section 1020.33(c)(2)(i).

c.

Please note any assumptions made in, or limitations of, the methods in determining
the imaging parameters.

308.3- 308.5 Provide information as outlined in Attachment A.308.3- 308.5 See Attachment A.
309.0

EQUIPMENT FAILURE EXPOSURE TERMINATION

309.1

Requirement
Means shall be provided to terminate the x-ray exposure automatically by either
deenergizing 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 (1020.33(f)(2)(i)).

309.2

Critical Parameters and “Worst Case” Conditions
Please note and describe any critical parameters and “worst conditions which are
unique to your system or test method.

309.3- 309.5 Provide information as outlined in Attachment A.
310.0

TOMOGRAPHIC PLANE LOCATION

310.1

Requirement
The distance between the indicated location of the tomographic plane or reference
plane and its actual location shall not exceed 5 millimeters (1020.33(g)(3)).

310.2

Critical Parameters and “Worst Case” Conditions
Please note and describe any critical parameters and “worst case” conditions which are
unique to your system or test method.

310.3- 301.5 Provide information as outlined in Attachment A.
311.0

ILLUMINATION LEVELS OF THE LIGHT SOURCE

311.1

Requirement
If a device using a light source is used to satisfy the requirements of paragraph
1020.33(g)(1) & (2), the light source shall permit visual determination of the location of
the tomographic plane or reference plane under ambient light conditions of up to 500
lux (1020.33(g)(5)).

14
FORM FDA 3627 (11/10)

311.2

Critical Parameters and “Worst Case” Conditions
Please note and describe any critical parameters and “worst case” conditions which
are unique to your system or test method.

311.3- 311.5 Provide information as outlined in Attachment A.
312.0

SHUTTER LEAKAGE RADIATION

312.1

Requirement
For systems that allow high voltage to be applied to the x-ray tube continuously and that
control the emission of x-rays with a shutter, the radiation emitted shall not exceed 100
milliroentgens (2.58 x 10-5 coulomb/kilogram) in 1 hour at any point 5 centimeters
outside the external surface of the housing of the scanning mechanism when the
shutter is closed. Compliance shall be determined by measurements averaged over an
area of 100 square centimeters with no linear dimension greater than 20 centimeters
(1020.33(h)(2)).

312.2

Critical Parameters and “Worst Case” Conditions
a.

For any test using a scan of the diagnostic source assembly, the rate of scan
specified in the test method(s) must account for the response time of the radiation
instrumentation.

b.

Please note and describe any critical parameters and “worst case” conditions which
are unique to your system or test method.

312.3- 312.5 Provide information as outlined in Attachment A.
313.0

SCAN INCREMENT ACCURACY

313.1

Requirement
The deviation of indicated scan increment from actual scan increment shall not exceed
1 mm. Compliance shall be measured as follows: The determination of the deviation of
indicated versus actual scan increment shall be based on measurements taken with a
mass, less than or equal to 100 kilograms, on the patient support device. The patient
support device shall be moved from a typical starting position to the maximum
longitudinal extent or 30 centimeters, whichever is less, and then returned to the
starting position. Measurement of actual versus indicated scan increment may be taken
anywhere along this travel (1020.33(i)).

313.2

Critical Parameters and “Worst Case” Conditions
Please note and describe any critical parameters and “worst case” conditions which are
unique to your system or test method.

313.3- 313.5 Provide information as outlined in Attachment A.
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FORM FDA 3627 (11/10)

This page is deliberately blank.

16
FORM FDA 3627 (11/10)

ATTACHMENT A
The information below is applicable to Part 300.
For each section answered in Part 300, provide the following information. Clearly relate the
response to the subsection of Part 300 to which it is applicable. For example, the responses to
Section 301.0 should be labeled 301.3 thru 301.5, as appropriate.
30X-3 Prototype Testing
a.

Provide a description of the direct test method (i.e., one that directly measures the
parameter in question) employed in testing and/or measuring the parameter for
each model with respect to this requirement.

b.

Identify the instrument(s) used for the test by manufacturer and model number.
Answer the appropriate section in Part 400 for this instrument(s).

c.

Provide sample raw test data.

d.

If the actual compliance value is calculated from the raw test data, provide a sample of
calculated compliance values complete with an explanation of any correction
factors employed.

e.

A statement indicating whether the maximum CTDI is obtained from integration
of the dose profile for a single scan or from a direct measurement of the average dose
in an interval equal to the slice thickness at the center of a series of 14 scans that are
spaced by the nominal tomographic slice thickness.

30X-4 Production Testing
a.

Describe all methods employed in direct and indirect testing of each model with
respect to this requirement.

b.

If an indirect test is used to measure compliance, explain why it is an accurate
indication of compliance with this requirement.

c.

Submit the technical data that supports the use of the test in part b.

d.

Provide a copy of the detailed instructions for performing each test. Attach as
APPENDIX F.

e.

Identify the instrument(s) used for each test by manufacturer and model number.
Answer the appropriate section in Part 400 for each instrument(s).

17
FORM FDA 3627 (11/10)

f.

For each of the above test methods, give the page number of your detailed
instructions for performing the test and indicate where the rejection limits are
specified.

g.

For each of the above test methods, provide sample raw test data.

h.

If the actual compliance value is calculated from the raw test data, provide a sample
of calculated compliance values complete with an explanation of any correction
factors employed.

i.

If you do not test 100 percent of the produced models, answer the questions in
Section 402.0, Part 400.

j.

A statement indicating whether the maximum CTDI is obtained from integration
of the dose profile for a single scan or from a direct measurement of the average dose
in an interval equal to the slice thickness at the center of a series of 14 scans that are
spaced by the nominal tomographic slice thickness.

30X-5 Assembler Testing
a-i.

If test instructions are provided to the assembler, answer the questions in 30X.4 with
respect to assembler testing. Note: The information requested in 30X.5 (d) (i.e., a copy of
detailed instructions for performing each test) should have already been provided in
APPENDIX B and thus may be referenced by indicating the appropriate page numbers.

18
FORM FDA 3627 (11/10)

PART 400 - COMMON ASPECTS
401.0 INSTRUMENTATION
401.1

401.2

401.3

Radiation Measurement
a.

Describe each radiation measurement instrument that you refer to in Part 300,
giving the following: manufacturer and model number if the instrument is
commercially available; type of instrument; precision; accuracy; response time;
energy dependence; angular response; exposure rate dependence; ranges; and
effective measurement area.

b.

Describe the procedures used for calibration of each instrument including the
interval of time between calibrations.

c.

How do you assure proper day-to-day operation of each instrument?

Illuminance
a.

Describe each illuminance measurement instrument that you refer to in Part 300,
giving the following: manufacturer and model number if the instrument is
commercially available; type of instrument; precision; accuracy; and ranges.

b.

Describe the procedures used for calibration of each instrument including the
interval of time between calibrations.

c.

How do you assure proper day-to-day operation of each instrument?

Electrical Measurement
a.

Describe each electrical measurement instrument that you referred to in Part 300,
giving the following: type of instrument; manufacturer and model number if the
instrument is commercially available; rated accuracy; precision; ranges; and
response time. If any number of commercially available instrument with certain
basic characteristics may be used, it is sufficient to state the minimum accuracy,
precision, ranges, response time, and so forth, of the class of instruments that will
be used. If any instrument is unique or of special manufacture, then the
manufacturer and model number should be stated.

b.

Describe the procedures used for calibration of each instrument including the
interval of time between calibrations.

c.

Show where each instrument listed in 401.3(a) is connected during testing with the
use of schematic diagrams

19
FORM FDA 3627 (11/10)

401.4

Other Measurements
a.

Describe each measurement instrument (other than radiation, illuminance or
electrical) that you refer to in Part 300, giving the following: type of instrument;
manufacturer and model number if the instrument is commercially available; rated
accuracy; precision; and ranges. If any number of commercially available
instruments with certain basic characteristics may be used, it is sufficient to state
the minimum accuracy, precision ranges, and so forth, of the class of instruments
that will be used. If any instrument is unique or of special manufacture, however,
then the manufacturer and model number should be stated.

b.

Describe the procedures used for calibration of each instrument including the
interval of time between calibrations.

402.0

SAMPLING

402.1

Description
a.

Describe the sampling plan used and provide the parameters of the plan (e.g., lot
size, sample size, rejection criterion).

b.

Describe the procedure
randomness is assured.

c.

Describe the action taken if the sampling plan leads to a rejection decision.

used

for

20
FORM FDA 3627 (11/10)

selecting

the

sample

and

indicate

how