X-Ray Safety

Did you know?

There are natural and artificial sources of ionizing radiation.

Summary

X-rays refer to a kind of electromagnetic radiation generated when a strong electron beam bombards metal inside a glass tube. The frequency of this radiation is very high - 0.3 to 30 Ehz (exahertz or billion gigahertz). There are natural and artificial sources of ionizing radiation. Artificial sources of radiation include X-ray machines, radioactive isotopes used in nuclear medicine, gamma cameras, nuclear gauges, and nuclear power plants.

The radiation dose relates to the amount of radiation energy absorbed by the human body. To account for the way in which different types of radiation cause harm to tissue or an organ, the radiation dose is expressed as the equivalent dose in units of sievert (Sv). The dose in Sv is equal to the total external and internal "absorbed doses" multiplied by a "radiation weighting factor." [Reg. 91-191, S.298.1]

The main methods to control radiation exposure include engineering controls, administrative controls and personal protective equipment. Examples of these controls include:

  • Education and training
  • Reducing exposure time
  • Increasing the distance from the radiation source
  • Using a physical barrier that modifies the pathway between the employee and source of radiation (e.g., concrete or lead)
  • Monitoring of exposures (individual and collective monitoring)
    • Recording exposures
    • Providing health surveillance
    • Promoting a health and safety culture
    • Complying with established radiation exposure (dose) limits

When operating x-ray equipment to irradiate a human, the operator must be: [Reg. 91-191, S.298.11(1)]

  • A radiation technologist registered with the New Brunswick Regulatory College for Medical Radiology Technologists,
  • A dental hygienist registered with the New Brunswick College of Dental Hygienists,
  • A formally trained dental assistant registered with the New Brunswick Dental Society,
  • A dentist registered with the New Brunswick Dental Society,
  • An interventional radiologist or an interventional cardiologist registered with the New Brunswick Medical Society,
  • A chiropractor registered with the New Brunswick Chiropractors Association, or
  • A student undergoing a course of instruction in a school approved by the Canadian Association of Medical Radiation Technologists, the Canadian Medical Association, the Canadian Dental Association or the Canadian Chiropractic Association.

When operating x-ray equipment to irradiate animals or items other than a human, the operator must be: [Reg. 91-191, S.298.11(2)]

  •  competent in maintaining or testing of x-ray equipment,
  • competent in x-ray radiation physics,
  • licensed as a veterinarian by the New Brunswick Veterinary Medicine Association,
  • certified as a Level I, II or III industrial radiographer, in accordance with the Canadian General Standards Board (CGSB) standard CAN/CGSB-48.9712-2014 “Non-Destructive Testing-Qualification and Certification of NDT Personnel”, or a standard offering equivalent or better protection, or
  • working under the direct and close supervision of a person referred to in this list above.

While respecting the information above, any person may operate x-ray equipment, other than for the irradiation of humans, if the x-ray source, the object or part of the object being exposed to X-rays, and any detection device are enclosed in a cabinet that prevents access to and protection for persons from exposure to the X-ray beam. [Reg. 91-191, S.298.11(3)]

X-ray equipment

An employer and an employee must make sure that the equipment is operated, maintained, inspected, and repaired according to the manufacturer’s instructions, the Radiation Emitting Devices Act (Canada), appropriate safety codes on radiation, and any other procedure approved by the Chief Compliance Officer as required. [Reg. 91-191, S.298.2]

Owners must:

Note that exposure limits to an employee can exclude natural radiation and radiation exposure from personal medical and dental procedures. [Reg. 91-191, S.298.21(4)] Owners must also make sure that any x-ray radiation worker who is a nuclear energy worker does not exceed a combined dose of ionizing radiation that are higher than the limits in the Nuclear Safety and Control Act. [Reg. 91-191, S.298.3]

  • Not allow the x-ray radiation worker to continue work that might expose them further when that employee has exceeded any of the dose limits, until the Chief Compliance Officer approves further work. [Reg. 91-191, S.298.4]
  • Make sure that each employee is informed (in writing) that they are an x-ray radiation worker and what the specified dose limits are. [Reg. 91-191, S.298.5]
  • Maintain records for each x-ray radiation worker, including their date of birth, gender, date of becoming an x-ray radiation worker, weekly radiation exposure and number of hours worked per week. [Reg. 91-191, S.298.6(1)]
  • When required by the Safety Codes, provide an x-ray radiation employee with a personal dosimeter, maintain each radiation exposure report for at least three years, and make sure the employee is told about their exposure within 72 hours when a single or cumulative exposure of 5.0 mSv or greater is reached [Reg. 91-191, S.298.7(1)] unless it can be shown that the exposure will not be more than 1 mSv per year, then no ongoing monitoring or record keeping is required. [Reg. 91-191, S.298.7(3)]
  • Request, with the consent of the employee, a medical examination when there is reason to believe that the employee has received an acute whole-body does of ionizing radiation more than 500 mSv, or an extremity exposure more than 5000 mSv. [Reg. 91-191, S.298.8(1)] This medical exam should be done during normal working hours for the employee, and any costs required paid by the owner.

Employees

An X-ray radiation worker must inform the owner of their pregnancy as soon as they become aware of being pregnant. [Reg. 91-191, S.298.9]

Legislation

General Regulation - Occupational Health and Safety Act

N.B. Reg. 91-191

Part XIX.1 RADIATION SAFETY

Section 298.1 Definitions

298.1 The following definitions apply in this Part.

"absorbed dose" means the average energy absorbed per unit mass of matter resulting from exposure to ionizing radiation.

"E or effective dose" means the weighted sum of all the equivalent doses received by organs and tissues in a body.

"H or equivalent dose" means a dose of ionizing radiation absorbed by an organ or tissue, equivalent in terms of specified biological damage to a deposition of energy measured in

  • (a) a unit of absorbed dose, equivalent to one joule of energy per kilogram of material, or
  • (b) a unit of air kerma, equivalent to one joule of energy per kilogram of air.

"mSv" means a unit of equivalent dose numerically equal in the case of X-rays to absorbed dose.

"radiation" means ionizing or non-ionizing energy in the form of atomic particles or electromagnetic or acoustic waves.

"X-ray radiation worker" means an employee whose occupation requires them to be exposed to radiation emitted by X-ray equipment.

[N.B. Reg. 2024-38, s. 104]

Section 298.2 X-ray equipment

298.2 An employer and an X-ray radiation worker shall each ensure that X-ray equipment is installed, used, maintained, repaired and inspected in accordance with

  • (a) the manufacturer’s specifications,
  • (b) the Radiation Emitting Devices Act (Canada),
  • (c) the appropriate safety code listed below, as published by the Minister of Health Canada and amended from time to time,
    • (i) Safety Code 28: "Radiation Protection in Vet‐ erinary Medicine: Recommended Safety Procedures for Installation and Use of Veterinary X-Ray Equipment" ,
    • (ii) Safety Code 29: "Requirements for the Safe Use of Baggage X-Ray Inspection Systems" ,
    • (iii) Safety Code 30 (2022): "Radiation Protection in Dentistry - Safety Procedures for the Installation, Use and Control of Dental X-ray Equipment" ,
    • (iv) Safety Code 32: "Safety Requirements and Guidance for Analytical X-Ray Equipment" ,
    • (v) Safety Code 34: "Radiation Protection and Safety for Industrial X-ray Equipment" ,
    • (vi) Safety Code 35: "Safety Procedures for the Installation, Use and Control of X-ray Equipment in Large Medical Radiological Facilities" , and
    • (vii) Safety Code 36: "Radiation Protection and Quality Standards in Mammography - Safety Procedures for the Installation, Use and Control of Mammographic X-ray Equipment", and
  • (d) any other procedure approved by the Chief Compliance Officer.

[N.B. Reg. 2024-38, s. 104]

Section 298.3 Nuclear energy worker

298.3 Despite any other provision of this Part, when an employer employs an X-ray radiation worker who is a nuclear energy worker as defined in the Nuclear Safety and Control Act (Canada) and whose total radiation exposure may be due to X-rays and other types of ionizing radiation, the employer shall ensure the combined dose of ionizing radiation received by the X-ray radiation worker does not exceed the limits specified in the Nuclear Safety and Control Act (Canada).

[N.B. Reg. 2024-38, s. 104]

Section 298.4 Exposure

298.4 An employer shall ensure that an X-ray radiation worker whose radiation exposure in any year exceeds the dose limits specified in subsection 298.21(2) does not engage for the remainder of that year in work that is likely to add to the X-ray radiation worker’s cumulative radiation exposure unless the Chief Compliance Officer approves the work.

[N.B. Reg. 2024-38, s. 104]

Section 298.5 Duty to inform

298.5 At the time that employment begins, an employer shall inform an X-ray radiation worker, in writing, of the dose limits specified in subsection 298.21(2) and the importance of informing the employer, as soon as the circumstances permit, in writing, that the X-ray radiation worker is pregnant.

[N.B. Reg. 2024-38, s. 104]

Section 298.6 Records
  • 298.6 (1) An employer shall maintain a record for each X-ray radiation worker containing the following information:
    • (a) the X-ray radiation worker’s date of birth;
    • (b) the X-ray radiation worker’s sex;
    • (c) the date on which the X-ray radiation worker began employment;
    • (d) the X-ray radiation worker’s weekly radiation exposure; and
    • (e) the number of hours worked per week by the X-ray radiation worker.
  • (2) An employer shall ensure the record for each X-ray radiation worker is made available to an officer on request and shall retain the record for at least three years after the termination of employment of the X-ray radiation worker.

[N.B. Reg. 2024-38, s. 104]

Section 298.7 Radiation exposure
  • 298.7 (1) An employer who is required to provide an X-ray radiation worker with a personal radiation monitoring device shall maintain a report indicating the radiation exposure of the X-ray radiation worker for at least three years from the date the report is made.
  • (2) In the event of a single or cumulative radiation exposure of 5 mSv or greater, an employer shall inform the X-ray radiation worker of their radiation exposure within 72 hours after the employer becomes aware of the exposure.
  • (3) If an employer is capable of demonstrating that the radiation exposure of X-ray radiation workers will not exceed 1 mSv per year, the employer is not required to monitor the radiation exposure of X-ray radiation workers or maintain records indicating the radiation exposure of X-ray radiation workers.

[N.B. Reg. 2024-38, s. 104]

Section 298.8 Medical examination
  • 298.8 (1) An employer who has reason to believe that an X-ray radiation worker has received an acute whole body dose of ionizing radiation in excess of 500 mSv or an extremity exposure exceeding 5,000 mSv resulting from the operation of X-ray equipment shall ensure that the X-ray radiation worker undergoes a medical examination.
  • (2) The cost of a medical examination carried out under this section shall be paid by the employer, and the medical examination shall, when the circumstances permit, be carried out during the normal working hours of the X-ray radiation worker.

[N.B. Reg. 2024-38, s. 104]

Section 298.9 Pregnancy

298.9 An X-ray radiation worker shall, as soon as the circumstances permit, inform the employer in writing of their pregnancy.

[N.B. Reg. 2024-38, s. 104]

Section 298.11 Operator qualifications
  • 298.11(1) A person who operates X-ray equipment for the irradiation of human beings shall be
    • (a) a radiation technologist registered with the New Brunswick Regulatory College for Medical Radiology Technologists,
    • (b) a dental hygienist registered with the New Brunswick College of Dental Hygienists,
    • (c) a formally trained dental assistant registered with the New Brunswick Dental Society,
    • (d) a dentist registered with the New Brunswick Dental Society,
    • (e) an interventional radiologist or an interventional cardiologist registered with the New Brunswick Medical Society,
    • (f) a chiropractor registered with the New Brunswick Chiropractors Association, or
    • (g) a student undergoing a course of instruction in a school approved by the Canadian Association of Medical Radiation Technologists, the Canadian Dental Association, the Canadian Medical Association or the Canadian Chiropractic Association.
  • (2) A person who operates X-ray equipment other than for the irradiation of human beings shall
    • (a) be competent in maintaining or testing X-ray equipment,
    • (b) be competent in X-ray radiation physics,
    • (c) be licensed as a veterinarian by the New Brunswick Veterinary Medicine Association,
    • (d) be certified as a Level I, II or III industrial radiographer, in accordance with the CGSB standard CAN/CGSB-48.9712-2014, Non-Destructive Testing - Qualification and certification of NDT Personnel or a standard offering equivalent or better protection, or
    • (e) work under the direct and close supervision of a person referred to in paragraphs (a) to (d).
  • (3) Despite subsection (2), any person may operate X-ray equipment other than for the irradiation of human beings if the X-ray source, the object or a portion of the object being exposed to X-rays and any detection device are enclosed within a cabinet preventing access to and protecting persons from exposure to the X-ray beam.

[N.B. Reg. 2024-38, s. 104]

Section 298.21 Dose limits
  • 298.21 (1) An employer or an owner of X-ray equipment shall ensure that X-ray equipment is installed in a place that is shielded, using as dose constraint for design purposes the dose limits set out in subsection (2).
  • (2) An employer or an owner of X-ray equipment shall ensure that X-ray equipment is used and maintained in a manner so that an X-ray radiation worker’s radiation exposure does not exceed the following dose limits:
    • (a) whole body (E or effective dose) 20 mSv per year;
    • (b) lens of the eye (H or equivalent dose) 150 mSv per year; and
    • (c) the skin of hands, feet and the face (H or equivalent dose) 500 mSv per year.
  • (3) An employer shall ensure that an X-ray radiation worker who has informed the employer in writing that they are pregnant does not receive a radiation exposure to the surface of their abdomen in excess of 2 mSv for the balance of the pregnancy starting from the date on which the employer is informed of the pregnancy.
  • (4) The dose limits shall not include natural radiation and radiation exposure from personal medical and dental procedures.

[N.B. Reg. 2024-38, s. 104]