Radiation Protection in Mammography: Recommended Safety Procedures for the Use of Mammographic X-Ray Equipment - Safety Code 33

2. Principal aims and scope of the Safety Code

This Safety Code is concerned with the protection of all individuals who may be exposed to ionizing radiation emitted by X-ray equipment used in the practice of mammography. The principal aims of this Safety Code are:

• to minimize patient exposure to radiation consistent with obtaining images of optimal diagnostic quality during mammography;
• to ensure adequate protection of personnel operating and maintaining mammographic X-ray equipment; and
• to ensure adequate protection of other personnel and the general public in the vicinity of areas where mammographic X-ray equipment is used.

To assist in achieving these objectives, this Safety Code:

1. sets out the relative responsibilities of the owner, radiologist, radiology technologist, and medical physicist;
2. presents recommended practices for minimizing patient, personnel and general public exposure to radiation doses and for ensuring that mammographic X-ray equipment is used in a safe manner;
3. specifies minimum standards of design, construction and performance for mammographic X-ray equipment;
4. presents recommended practices to optimize image quality; and
5. supplies information required to implement and operate a Quality Assurance program for the facility.

3. Responsibility and personnel

Although staff responsibilities described below are grouped by each type of personnel or profession, to obtain the optimal level of radiation safety and image quality, it is imperative that full cooperation exists among all concerned parties.

3.1 Owner

The owner is ultimately responsible for radiation safety and image quality of a mammographic X-ray facility. It is the responsibility of the owner to ensure that the equipment and the facilities in which such equipment is installed and used meet all applicable radiation safety standards.

The owner may delegate this responsibility to staff. How this responsibility is delegated will depend upon how many staff there are, on the nature of the operation, and on the number of mammographic X-ray units owned. It is acceptable for facilities to have some of the duties listed assumed by suitable consulting bodies such as medical physics consulting organizations. In any event, one or more persons must undertake responsibility for:

1. ensuring that the installation complies with all applicable regulatory requirements; and that radiation levels are consistent with the recommended dose limits given in Appendix I;
2. consulting with the appropriate government agency(ies)
   1. when a new facility is being constructed, or modification of an existing one is planned, to ensure that radiation safety is adequate,
   2. when mammographic X-ray equipment is purchased to ensure adequate radiation safety, and to register this equipment with the appropriate agency, and
   3. to set periodic scheduled inspections for the facility. In some jurisdictions, the agency responsible for inspections has the mandate for setting inspection schedules;
3. establishing safe working conditions according to the recommendations of this Safety Code and the statutory requirements of Federal or Provincial legislation, where applicable;
4. ensuring that
   1. the equipment functions properly, and is maintained correctly by competent personnel,
   2. safe operating procedures are established and are followed,
   3. Quality Control monitoring of mammographic X-ray equipment, image processor, and ancillary equipment is carried out,
   4. technologists are properly trained in the operation of the equipment being used, and
   5. technologists-in-training and inexperienced personnel operate mammographic X-ray equipment only under the direct supervision of a licensed or certified technologist;
5. implementing and maintaining an effective diagnostic imaging Quality Assurance program for the facility, including Quality Control and record keeping;
6. declaring who is to be considered an occupationally exposed person where this person may receive a radiation dose in excess of 1/20th of the recommended dose limit specified in Appendix I, keeping records of occupational exposures received by personnel, and investigating any exposure received by personnel in excess of 1/20th of the recommended dose limit; and
7. keeping records of radiation surveys, including summaries of corrective measures recommended and/or instituted, and organizing participation in a personnel radiation monitoring service, such as that provided by the Radiation Protection Bureau, Health Canada, Ottawa, Ontario, K1A 1C1; and
8. ensuring that personnel understand the contents of this Safety Code.

3.2 Radiologist

All radiologists must be licensed according to a recognized standard and must possess qualifications required by any relevant Federal and Provincial regulations or statutes. They must have received sufficient training in mammography and must receive continuing education. The radiologist must:

1. understand the contents of this Safety Code and follow the recommendations of Section 10;
2. communicate with staff any changes in image quality whether these changes are due to improper positioning, loading factors or image processing; and
3. participate fully in the Quality Assurance program.
   
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3.3 Medical Physicist

The medical physicist is an individual who has received adequate training and is sufficiently experienced in radiation protection, and the operation and testing of mammography X-ray equipment. The medical physicist should be available to act as advisor on all radiation protection and diagnostic image quality matters during the planning stages, the construction of the facility, the installation of the equip- ment, and should also be available for consultation during regular operation of the facility. The medical physicist should have responsibility for:

1. verifying the safety of an installation at the time of planning and construction, and ensuring that the installation complies with all applicable regulatory requirements;
2. reviewing the safety procedures periodically and recommending to the owner the necessary changes to ensure optimum patient and personnel safety, and instructing personnel in proper radiation protection practices;
3. ensuring that
   1. the Quality Assurance program is properly implemented and operated,
   2. the optimal level of diagnostic image quality is obtained, and
   3. appropriate Quality Control monitoring instruments are available and properly calibrated;
4. performing the required testing of mammographic X-ray equipment, image processor, and ancillary equipment;
5. ensuring that all safety devices recommended by this Safety Code are functioning and that appropriate warning signs are properly located; and
6. understanding the contents of this Safety Code.

3.4 Quality Control Technologist

There must be a staff member who is responsible for the optimization of image quality. This person must have received adequate training in mammography Quality Control and in the operation of Quality Control test equipment. Depending on the size of the facility these duties can be performed by a staff X-ray technologist on either a part-time or full-time basis. The Quality Control Technologist should have responsibility for:

1. ensuring that the optimal level of diagnostic image quality is maintained;
2. performing daily and routine Quality Control tests of mammographic X-ray equipment, image processor, and ancillary equipment and keeping record of these tests;
3. communicating with staff any changes in image quality;
4. participating fully in the Quality Assurance program; and
5. understanding the contents of this Safety Code.

3.5 X-ray Technologist

All mammographic X-ray technologists must be certified according to a recognized standard, such as that of the Canadian Association of Medical Radiation Technologists, and must possess qualifications required by any relevant Federal and Provincial regulations or statutes. They must have received adequate training, and must receive continuing education in mammography techniques and procedures. If technologists are to perform special techniques such as mammography of patients with breast implants, they must also receive adequate training in these techniques. The technologists must:

1. understand the contents of this Safety Code and follow the recommendations of Sections 9 and 10.3;
2. be aware of the radiation hazards associated with their work and their duty to protect themselves, their patients, and others;
3. be aware of the consequences of improperly performed mammographic procedures on image quality and patient doses;
4. have a thorough understanding of their profession and of safe working methods; and
5. participate fully in the Quality Assurance program.

In general, there is no reason to remove pregnant technologists from their duties of operating mammographic X-ray equipment. However, it is advised that an X-ray technologist should immediately notify the employer if she suspects that she is pregnant, in order that appropriate steps may be taken to ensure that her work duties during the remainder of the pregnancy are compatible with the recommended dose limits specified in Appendix I.