[Code of Federal Regulations]
[Title 21, Volume 8]
[Revised as of April 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR1000.55]

[Page 593-598]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 1000_GENERAL--Table of Contents
 
             Subpart C_Radiation Protection Recommendations
 
Sec. 1000.55  Recommendation for quality assurance programs in 
diagnostic radiology facilities.

    (a) Applicability. Quality assurance programs as described in 
paragraph (c) of this section are recommended for all diagnostic 
radiology facilities.
    (b) Definitions. As used in this section, the following definitions 
apply:
    (1) Diagnostic radiology facility means any facility in which an x-
ray system(s) is used in any procedure that involves irradiation of any 
part of the human body for the purpose of diagnosis or visualization. 
Offices of individual physicians, dentists, podiatrists, and 
chiropractors, as well as mobile laboratories, clinics, and hospitals 
are all examples of diagnostic radiology facilities.
    (2) Quality assurance means the planned and systematic actions that 
provide adequate confidence that a diagnostic x-ray facility will 
produce consistently high quality images with minimum exposure of the 
patients and healing arts personnel. The determination of what 
constitutes high quality will be made by the facility producing the 
images. Quality assurance actions include both ``quality control'' 
techniques and ``quality administration'' procedures.
    (3) Quality assurance program means an organized entity designed to 
provide ``quality assurance'' for a diagnostic radiology facility. The 
nature and extent of this program will vary with the size and type of 
the facility, the type of examinations conducted, and other factors.
    (4) Quality control techniques are those techniques used in the 
monitoring (or testing) and maintenance of the components of an x-ray 
system. The quality control techniques thus are concerned directly with 
the equipment.
    (5) Quality administration procedures are those management actions 
intended to guarantee that monitoring techniques are properly performed 
and evaluated and that necessary corrective measures are taken in 
response to monitoring results. These procedures provide the 
organizational framework for the quality assurance program.
    (6) X-ray system means an assemblage of components for the 
controlled production of diagnostic images with 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. Other components that function with the system, such as 
image receptors, image processors, view boxes, and darkrooms, are also 
parts of the system.
    (c) Elements. A quality assurance program should contain the 
elements listed in paragraphs (c)(1) through (10) of this section. The 
extent to which each element of the quality assurance program is 
implemented should be determined by an analysis of the facility's 
objectives and resources conducted by its qualified staff or by 
qualified outside consultants. The extent of implementation should be 
determined on the

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basis of whether the expected benefits in radiation exposure reduction, 
improved image quality, and/or financial savings will compensate for the 
resources required for the program.
    (1) Responsibility. (i) Responsibility and authority for the overall 
quality assurance program as well as for monitoring, evaluation, and 
corrective measures should be specified and recorded in a quality 
assurance manual.
    (ii) The owner or practitioner in charge of the facility has primary 
responsibility for implementing and maintaining the quality assurance 
program.
    (iii) Staff technologists will generally be delegated a basic 
quality assurance role by the practitioner in charge. Responsibility for 
specific quality control monitoring and maintenance techniques or 
quality administration procedures may be assigned, provided that the 
staff technologists are qualified by training or experience for these 
duties. The staff technologists should also be responsible for 
identifying problems or potential problems requiring actions beyond the 
level of their training. They should bring these problems to the 
attention of the practitioner in charge, or his or her representative, 
so that assistance in solving the problems may be obtained from inside 
or outside the facility.
    (iv) In facilities where they are available, physicists, supervisory 
technologists, or quality control technologists should have a major role 
in the quality assurance program. Such specialized personnel may be 
assigned responsibility for day-to-day administration of the program, 
may carry out monitoring duties beyond the level of training of the 
staff technologist or, if desired by the facility, may relieve the staff 
technologists of some or all of their basic monitoring duties. Staff 
service engineers may also be assigned responsibility for certain 
preventive or corrective maintenance actions.
    (v) Responsibility for certain quality control techniques and 
corrective measures may be assigned to personnel qualified by training 
or experience, such as consultants or industrial representatives, from 
outside of the facility, provided there is a written agreement clearly 
specifying these services.
    (vi) In large facilities, responsibility for long-range planning of 
quality assurance goals and activities should be assigned to a quality 
assurance committee as described in paragraph (c)(9) of this section.
    (2) Purchase specifications. Before purchasing new equipment, the 
staff of the diagnostic radiology facility should determine the desired 
performance specifications for the equipment. Initially, these 
specifications may be stated in terms of the desired performance of the 
equipment, or prospective vendors may be informed solely of the 
functions the equipment should be able to perform and asked to provide 
the performance specifications of items from their equipment line that 
can perform these functions. In either case, the responses of the 
prospective vendors should serve as the basis for negotiations to 
establish the final purchase specifications, taking into account the 
state of the art and balancing the need for the specified performance 
levels with the cost of the equipment to meet them. The final purchase 
specifications should be in writing and should include performance 
specifications. The availability of experienced service personnel should 
also be taken into consideration in making the final purchase decisions. 
Any understandings with respect to service personnel should be 
incorporated into the purchase specifications. After the equipment is 
installed, the facility should conduct a testing program, as defined in 
its purchase specifications, to ensure that the equipment meets the 
agreed upon specifications, including applicable Federal and State 
regulatory requirements. The equipment should not be formally accepted 
until any necessary corrections have been made by the vendor. The 
purchase specifications and the records of the acceptance testing should 
be retained throughout the life of the equipment for comparison with 
monitoring results in order to assess continued acceptability of 
performance.
    (3) Monitoring and maintenance. A routine quality control monitoring 
and maintenance system incorporating state-of-the-art procedures should 
be established and conducted on a regular schedule. The purpose of 
monitoring is

[[Page 595]]

to permit evaluation of the performance of the facility's x-ray 
system(s) in terms of the standards for image quality established by the 
facility (as described in paragraph (c)(4) of this section) and 
compliance with applicable Federal and State regulatory requirements. 
The maintenance program should include corrective maintenance to 
eliminate problems revealed by monitoring or other means before they 
have a serious deleterious impact on patient care. To the extent 
permitted by the training of the facility staff, the maintenance program 
should also include preventive maintenance, which could prevent 
unexpected breakdowns of equipment and disruption of departmental 
routine.
    (i) The parameters to be monitored in a facility should be 
determined by that facility on the basis of an analysis of expected 
benefits and cost. Such factors as the size and resources of the 
facility, the type of examinations conducted, and the quality assurance 
problems that have occurred in that or similar facilities should be 
taken into account in establishing the monitoring system. The monitoring 
frequency should also be based upon need and can be different for 
different parameters.
    (ii) Although the parameters to be monitored will vary somewhat from 
facility to facility, every diagnostic radiology facility should 
consider monitoring the following five key components of the x-ray 
system:
    (a) Film processing.
    (b) Basic performance characteristics of the x-ray unit.
    (c) Cassettes and grids.
    (d) View boxes.
    (e) Darkroom.
    (iii) Examples of parameters of the above-named components and of 
more specialized equipment that may be monitored are as follows:
    (a) For film processing:

An index of speed.
An index of contrast.
Base plus fog.
Solution temperatures.
Film artifact identification.

    (b) For basic performance characteristics of the x-ray unit:
    (1) For fluoroscopic x-ray units:

Table-top exposure rates.
Centering alignment.
Collimation.
kVp accuracy and reproducibility.
mA accuracy and reproducibility.
Exposure time accuracy and reproducibility.
Reproducibility of x-ray output.
Focal spot size consistency.
Half-value layer.
Representative entrance skin exposures.

    (2) For image-intensified systems:

Resolution.
Focusing.
Distortion.
Glare.
Low contrast performance.
Physical alignment of camera and collimating lens.

    (3) For radiographic x-ray units:

Reproducibility of x-ray output.
Linearity and reproducibility of mA stations.
Reproducibility and accuracy of timer stations.
Reproducibility and accuracy of kVp stations.
Accuracy of source-to-film distance indicators.
Light/x-ray field congruence.
Half-value layer.
Focal spot size consistency.
Representative entrance skin exposures.

    (4) For automatic exposure control devices:

Reproducibility.
kVp compensation.
Field sensitivity matching.
Minimum response time.
Backup timer verification.

    (c) For cassettes and grids:
    (1) For cassettes:

Film/screen contact.
Screen condition.
Light leaks.
Artifact identification.

    (2) For grids:

Alignment and focal distance.
Artifact identification.

    (d) For view boxes:

Consistency of light output with time.
Consistency of light output from one box to another.
View box surface conditions.

    (e) For darkrooms:

Darkroom integrity.
Safe light conditions.

    (f) For specialized equipment:
    (1) For tomographic systems:

Accuracy of depth and cut indicator.

[[Page 596]]

Thickness of cut plane.
Exposure angle.
Completeness of tomographic motion.
Flatness of tomographic field.
Resolution.
Continuity of exposure.
Flatness of cassette.
Representative entrance skin exposures.

    (2) For computerized tomography:

Precision (noise).
Contrast scale.
High and low contrast resolution.
Alignment.
Representative entrance skin exposures.

    (iv) The maintenance program should include both preventive and 
corrective aspects.
    (a) Preventive maintenance. Preventive maintenance should be 
performed on a regularly scheduled basis with the goal of preventing 
breakdowns due to equipment failing without warning signs detectable by 
monitoring. Such actions have been found cost effective if 
responsibility is assigned to facility staff members. Possible 
preventive maintenance procedures are visual inspection of the 
mechanical and electrical characteristics of the x-ray system (covering 
such things as checking conditions of cables, watching the tomographic 
unit for smoothness of motion, assuring cleanliness with respect to 
spilling of contaminants in the examination room or the darkroom, and 
listening for unusual noises in the moving parts of the system), 
following the manufacturer's recommended procedures for cleaning and 
maintenance of the equipment, and regular inspection and replacement of 
switches and parts that routinely wear out or fail. The procedures 
included would depend upon the background of the staff members 
available. Obviously, a large facility with its own service engineers 
can do more than an individual practitioner's office.
    (b) Corrective maintenance. For maximum effectiveness, the quality 
assurance program should make provision, as described in paragraph 
(c)(5) of this section, for ascertaining whether potential problems are 
developing. If potential or actual problems are detected, corrective 
maintenance should be carried out to eliminate them before they cause a 
major impact on patient care.
    (4) Standards for image quality. Standards of acceptable image 
quality should be established. Ideally, these should be objective, e.g., 
acceptability limits for the variations of parameter values, but they 
may be subjective, e.g., the opinions of professional personnel, in 
cases where adequate objective standards cannot be defined. These 
standards should be routinely reviewed and redefined as needed, as 
described in paragraph (c)(10) of this section.
    (5) Evaluation. The facility's quality assurance program should 
include means for two levels of evaluation.
    (i) On the first level, the results of the monitoring procedures 
should be used to evaluate the performance of the x-ray system(s) to 
determine whether corrective actions are needed to adjust the equipment 
so that the image quality consistently meets the standards for image 
quality. This evaluation should include analysis of trends in the 
monitoring data as well as the use of the data to determine the need for 
corrective actions on a day-by-day basis. Comparison of monitoring data 
with the purchase specifications and acceptance testing results for the 
equipment in question is also useful.
    (ii) On the second level, the facility quality assurance program 
should also include means for evaluating the effectiveness of the 
program itself. Possible means include ongoing studies of the retake 
rate and the causes of the repeated radiographs, examination of 
equipment repair and replacement costs, subjective evaluation of the 
radiographs being produced, occurrence and reasons for complaints by 
radiologists, and analysis of trends in the results of monitoring 
procedures such as sensitometric studies. Of these, ongoing studies of 
the retake rate (reject rate) and its causes are often the most useful 
and may also provide information of value in the first level of 
evaluation. Such studies can be used to evaluate potential for 
improvement, to make corrections, and to determine whether the 
corrective actions were effective. The number of rejects should be 
recorded daily or weekly, depending on the facility's analysis of its 
needs. Ideally, the reasons for the rejection

[[Page 597]]

should also be determined and recorded. Should determining these reasons 
be impossible on a regular basis with the available staff, the analysis 
should be done for a 2-week period after major changes have occurred in 
diagnostic procedures or the x-ray system and at least semi-annually.
    (6) Records. The program should include provisions for the keeping 
of records on the results of the monitoring techniques, any difficulties 
detected, the corrective measures applied to these difficulties, and the 
effectiveness of these measures. The extent and form of these records 
should be determined by the facility on the basis of its needs. The 
facility should view these records as a tool for maintaining an 
effective quality assurance program and not view the data in them as an 
end in itself but rather as a beginning. For example, the records should 
be made available to vendors to help them provide better service. More 
importantly, the data should be the basis for the evaluation and the 
reviews suggested in paragraphs (c)(5) and (10) of this section.
    (7) Manual. A quality assurance manual should be written in a format 
permitting convenient revision as needed and should be made readily 
available to all personnel. The content of the manual should be 
determined by the facility staff, but the following items are suggested 
as providing essential information:
    (i) A list of the individuals responsible for monitoring and 
maintenance techniques.
    (ii) A list of the parameters to be monitored and the frequency of 
monitoring.
    (iii) A description of the standards, criteria of quality, or limits 
of acceptability that have been established for each of the parameters 
monitored.
    (iv) A brief description of the procedures to be used for monitoring 
each parameter.
    (v) A description of procedures to be followed when difficulties are 
detected to call these difficulties to the attention of those 
responsible for correcting them.
    (vi) A list of the publications in which detailed instructions for 
monitoring and maintenance procedures can be found. Copies of these 
publications should also be readily available to the entire staff, but 
they should be separate from the manual. (Publications providing these 
instructions can usually be obtained from FDA or private sources, 
although the facility may wish to make some modifications to meet its 
needs more effectively.)
    (vii) A list of the records, with sample forms, that the facility 
staff has decided should be kept. The facility staff should also 
determine and note in the manual the length of time each type of record 
should be kept before discarding.
    (viii) A copy of each set of purchase specifications developed for 
new equipment and the results of the acceptance testing for that 
equipment.
    (8) Training. The program should include provisions for appropriate 
training for all personnel with quality assurance responsibilities. This 
should include both training provided before the quality assurance 
responsibilities are assumed and continuing education to keep the 
personnel up-to-date. Practical experience with the techniques conducted 
under the supervision of experienced instructors, either in the facility 
or in a special program, is the most desirable type of training. The use 
of self-teaching materials can be an adequate substitute for supervised 
instruction, especially in continuing education programs, if supervised 
instruction is not available.
    (9) Committee. A facility whose size would make it impractical for 
all staff members to meet for planning purposes should consider the 
establishment of a quality assurance committee whose primary function 
would be to maintain lines of communication among all groups with 
quality assurance and/or image production or interpretation 
responsibilities. For maximum communication, all departments of the 
facility with x-ray equipment should be represented. The committee may 
also be assigned policy-making duties such as some or all of the 
following:

Assign quality assurance responsibilities; maintain acceptable standards 
of quality; periodically review program effectiveness, etc. 
Alternatively, the

[[Page 598]]

duties of this committee could be assigned to an already-existing 
committee such as the Radiation Safety Committee. In smaller facilities, 
all staff members should participate in the committee's tasks. The 
Quality Assurance Committee should report directly to the head of the 
radiology department, or, in facilities where more than one department 
operates x-ray equipment, to the chief medical officer of the facility. 
The committee should meet on a regular basis.
    (10) Review. The facility's quality assurance program should be 
reviewed by the Quality Assurance Committee and/or the practitioner in 
charge to determine whether its effectiveness could be improved. Items 
suggested for inclusion in the review include:
    (i) The reports of the monitoring and maintenance techniques to 
ensure that they are being performed on schedule and effectively. These 
reports should be reviewed at least quarterly.
    (ii) The monitoring and maintenance techniques and their schedules 
to ensure that they continue to be appropriate and in step with the 
latest developments in quality assurance. They should be made current at 
least annually.
    (iii) The standards for image quality to ensure that they are 
consistent with the state-of-the-art and the needs and resources of the 
facility. These standards should be evaluated at least annually.
    (iv) The results of the evaluations of the effectiveness of the 
quality assurance actions to determine whether changes need to be made. 
This determination should be made at least annually.
    (v) The quality assurance manual should also be reviewed at least 
annually to determine whether revision is needed.

[44 FR 71737, Dec. 11, 1979]