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Clinic Policy Manual

Radiation Safety Policy

Subject: Radiation Safety Policy
Effective Date: January 1994
Revision Dates: August 2002, January, 2008, October 2009, February 2021, April 2023, November 2023

Purpose

This policy establishes mandatory protocols and procedures designed to:

  1. Minimize radiation exposure to patients and operators.
  2. Promote sound radiological health practices.
  3. Promote proper infection control during radiographic procedures.
  4. Ensure sound radiological practices in the research environment
  5. Standardize the process for obtaining, installing, and moving radiology equipment.
  6. Ensure strict adherence to ALARA (As low as reasonably achievable) standards.

List of acronyms used in this policy:

  • ALARA – As Low as Reasonably Achievable
  • CBCT – Cone Beam Computed Tomography
  • EH&S – Department of Environmental Health and Safety of UW
  • EHR – Electronic Health Record (including axiUm)
  • FDA – U.S. Federal Drug Administration
  • RSC – Radiation Safety Committee of EH&S
  • UW – University of Washington
  • UWSOD – UW School of Dentistry
  • WAC – State of Washington Administrative Code

General Policy

The responsibility for clinical radiation safety and infection control lies with every individual involved with diagnostic and research radiology including faculty, students, clinical staff, and all other individuals who are responsible for the proper use and maintenance of radiation equipment and supplies. The ultimate goal of this policy is to operate under the ALARA concept with regard to radiation exposure.

The principles of infection control as applied to clinical radiology and described in this policy and in the infection control manual of UWSOD entitled, Hazard Control in the Dental Environment, must be utilized in all UWSOD clinics where such services are rendered.

IMPLEMENTATION 

I. General Radiation Safety Issues 

A. Compliance Statement

These policies, procedures, and criteria adhere to both Federal and Washington State regulations for Radiation Protection and adopt the principles of the FDA Guidelines for Dental Radiographic Examinations. They have been developed in cooperation with the Radiation Safety Committee (RSC) of the UW Department of Environmental Health and Safety (EH&S). All members of the UWSOD workforce are required to comply with this policy, including faculty, students, clinical staff, volunteers, residents, and all other individuals who are responsible for the proper use and maintenance of radiation equipment and supplies involved in diagnostic radiology and imaging. These policies include conventional radiological procedures and CBCT.

Members of the UWSOD workforce must:

  • Adhere to accepted protocols for the safe operation of radiologic equipment as defined by RSC.
  • Follow sound and logical radiological health practices as defined by RSC.
  • Report any suspected health hazards to the UWSOD Department of Radiology and to the UW RSC.
  • Adhere to the infection control policy of the school during radiographic procedures and at all other times.
  • Consult with the UWSOD Department of Radiology prior to obtaining, installing, or moving any type of radiologic equipment.
  • Strictly adhere to ALARA standards.

B. Responsibility for Monitoring

EH&S Radiation Safety is responsible for implementation of radiation safety measures and controls thereof. They must perform annual inspections. These annual inspections will include but are not limited to:

  • Measurements of radiation in controlled and non-controlled areas.
  • Performance testing of radiographic units with respect to State and Federal regulatory codes.
  • Identification of non-compliance with University policy or regulatory codes.
  • Evaluation of radiological safety programs by observing their effectiveness in providing protection and the level of compliance.
  • Evaluation of the current facility design and equipment safety controls.

A board certified Oral and Maxillofacial Radiologist from the UWSOD Department of Oral Medicine, Radiology Division must serve on the UW RSC, act as a liaison between individual UWSOD users of radiation and the RSC and assist EH&S Radiation Safety in the implementation of the UWSOD Radiation Safety Policy. This position will help to develop radiation safety training that includes ALARA principles, radiographic procedures, safe operation of each type of radiographic unit the operator will be operating, selection of proper techniques from a technique chart, patient radiation protection, proper image receptors processing, and any other topics necessary to meet the requirements specified in WAC 246-225A-020 sub-section (1).

C. Radiographic equipment operator training, experience, and requirements

All operators of radiographic equipment, including any new UWSOD workforce member who may be operating radiographic equipment, must complete radiation safety training and equipment-specific training prior to operating radiographic equipment and annually thereafter.

Only individuals described in this section are permitted to use diagnostic radiographic equipment in the practice of dentistry at UWSOD.

Predoctoral Students: Predoctoral students may operate radiographic equipment subject to the following restrictions:

  • The student must have completed all required didactic and preclinical training and obtained a passing grade in their UWSOD courses in oral radiology.
  • The student must have completed and be up to date in all annual radiation safety training.
  • The following are required for each and every radiographic exposure for a patient, and not on a “per-visit” basis. This includes re-takes and radiographic exposures that are performed as part of and during a larger procedure.
  • For each radiographic exposure for a patient, the student must:
    1. Record in that patient’s Electronic Health Record (EHR) (including axiUm) the following information:
      1. description of the clinical situation requiring a radiographic image.
      2. description of the radiographic image (location, type, other details)
    2. Before they perform each radiographic exposure, the student must obtain verbal or signed authorization of the prescription for the radiographic exposure by a clinical attending (faculty or instructor) of UWSOD. The prescription can either be the Radiographic Request Referral Form for images taken in radiology clinic or have the planned radiographic procedure code approved in the EHR for images taken in any other clinic. When verbal authorization is given prior to the exposure, signed authorization must be documented at the end of the appointment.
  • After they perform each radiographic exposure for a patient, the student must:
    1. Obtain the signed approval in the EHR of the quality of the radiograph by clinical attending (faculty or instructor) of UWSOD who prescribed the radiograph.
    2. Ensure that the radiograph has been interpreted and that its interpretation is recorded and signed in the EHR.
    3. Ensure that the correct billing code, if any, has been entered and approved.

Graduate Students: Graduate students/residents without a current valid Washington license may operate radiographic equipment subject to the following restrictions:

  • The graduate student/resident must have earned a dental degree.
  • The graduate student/resident must have completed and be up to date in all annual radiation safety training
  • The following are required for each and every radiographic exposure for a patient, and not on a “per-visit” basis. This includes re-takes and radiographic exposures that are performed as part of and during a larger procedure.
  • Unless they are a licensed graduate student/resident with a waiver from faculty, for each radiographic exposure for a patient, the graduate student/resident must:
    • Record in that patient’s EHR the following information:
      • description of the clinical situation requiring a radiographic image.
      • description of the radiographic image (location, type, other details)
    • Before they perform each radiographic exposure, the graduate student/resident must obtain verbal or signed authorization of the prescription for the radiographic exposure by a clinical attending (faculty or instructor) of UWSOD. The prescription can either be the Radiographic Request Referral Form for images taken in radiology clinic or have the planned radiographic procedure code approved in the EHR for images taken in any other clinic. When verbal authorization is given prior to the exposure, signed authorization must be documented at the end of the appointment.
  • Unless they are a licensed graduate student/resident with a waiver from faculty, after they complete, they perform each radiographic exposure for a patient, the student must:
    • Obtain the signed approval in the EHR of the quality of the radiograph by clinical attending (faculty or instructor) of UWSOD who prescribed the radiograph.
    • Ensure that the radiograph has been interpreted and that its interpretation is recorded and signed in the EHR.
    • Ensure that the correct billing code, if any, has been entered and approved.

If they are a licensed graduate student/resident with a waiver from faculty, the following conditions apply:

Radiology Technicians and dental assistants: UWSOD radiology technicians and dental assistants may operate radiographic equipment subject to the following restrictions:

  • They must have adequate training in radiographic techniques.
  • They must have completed and be up to date in all annual radiation safety training.
  • The following are required for each and every radiographic exposure for a patient, and not on a “per-visit” basis. This includes re-takes and radiographic exposures that are performed as part of and during a larger procedure.

For each radiographic exposure for a patient, they must:

  • Obtain verbal or signed authorization of the prescription for the radiographic exposure by a clinical attending (faculty or instructor) of UWSOD before they perform each radiographic exposure. The prescription can either be the Radiographic Request Referral Form for images taken in radiology clinic or have the planned radiographic procedure code approved in the EHR for images taken in any other clinic. When verbal authorization is given prior to the exposure, signed authorization must be documented at the end of the appointment.
  • Ensure a member of the faculty is available for consultation if required.

After they complete, they perform each radiographic exposure for a patient, they must:

  • Obtain the signed approval in the EHR (MiPACS) of the quality of the radiograph by clinical attending (faculty or instructor) of UWSOD who prescribed the radiograph.

Faculty members: All members of the faculty of the UWSOD possessing a dental degree and who are current with annual radiation safety training are authorized to prescribe radiographic examinations.

Researchers: The operation of radiographic equipment for research is authorized but limited to:

  • The radiographic operator must have adequate training in radiographic techniques and be current with annual radiation safety training.
  • A member of the faculty of UWSOD must authorize the radiographic exposure, as evidenced by the faculty member’s signature or digital approval.
  • A member of the faculty must be available for consultation when required.

D. Radiation Protection Standards

Occupational dose limits are specified in WAC 246-221-010. For adults, the annual limits are:

  • Total effective dose equivalent to the whole body is 0.05 Sv (5 rem).
  • Dose equivalent limit for the lens of the eye is 0.15 Sv (15 rem); and
  • Dose equivalent limit to the skin of the whole body and to the skin of any extremity is 0.50 Sv (50 rem).

Monitoring will be required for any individual who could potentially receive a dose in excess of 10% of the annual occupational dose limits listed above. Additionally, any individuals who must hold patients or image receptors during radiographs must be monitored for occupational radiation exposure.

WAC 246-221-055 requires assessment and control of fetal doses. A pregnant worker, including students, staff, and faculty must voluntarily declare their pregnancy in writing to their employer (or to their supervising faculty member, if a student) and include their estimated date of conception. The dose equivalent to an embryo/fetus during the entire pregnancy must not exceed 5 mSv (0.5 rem). Once pregnancy has been declared, every effort should be made to avoid substantial variation above a monthly dose rate of 0.5 mSv (0.05 rem) to the embryo/fetus. Contact EH&S Radiation Safety to declare a pregnancy and receive dosimeters to evaluate fetal doses. If a radiographic equipment operator does not declare their pregnancy in writing through EH&S Radiation Safety, they are not considered to be pregnant and the 0.05 Sv (5 rem) occupational exposure limit applies.

WAC 296-125-030 prohibits minors (younger than 18 years of age) from working in occupations involving potential exposure to radioactive substances and to ionizing radiation. Therefore, minors working at UWSOD must not be permitted to operate radiographic equipment or work near radiographic equipment during its operation.

Any individual monitoring device used for monitoring the dose to the whole body must be worn at the unshielded location of the whole body likely to receive the highest exposure. When a protective apron is worn, the location of the individual monitoring device is typically at the neck (collar). Any individual monitoring device used for monitoring the dose to an extremity must be worn on the hand likely to receive the highest exposure.

Any additional individual monitoring device used for monitoring the dose to an embryo/fetus of a declared pregnant person must be located at the waist under any protective apron being worn by the pregnant person.

II.  Guidelines for Prescribing Dental Radiographs 

A. General Principles

The goal of every radiographic examination will be to seek information which will influence the diagnosis and treatment of the patient, thereby providing a benefit which otherwise could not be realized.

The exposure of each patient will be as individualized as feasible. There must be no “routine” radiographic examinations. Radiographic examinations must be carried out solely based on clinical indications. Radiographs must not be taken solely for legal, documentary, teaching, or administrative purposes.

To minimize unnecessary radiation to the patient, previous radiographs of the patient should be obtained. These will serve as important guides for the ordering of new radiographs and to provide a better understanding of disease progress.

B. Prescription Guidelines

The Guidelines for prescribing dental radiographs are based on the recommendations issued by ADA Guidelines published in 2012.

III.    Radiation Protection Measures for Patients and Personnel 

A. Patient Protection from Ionizing Radiation

  • The radiographic equipment operator must employ those operating parameters (kVp, mA, exposure time, detector, and rectangular collimation), which result in the lowest possible radiation dose to the patient and still produce desired diagnostic information.
  • For intraoral radiographs, a lead impregnated apron can be used to shield the trunk of the body and the gonads of the patient. The lead equivalent of the apron must be at least 0.25 mm. A conventional lap apron should not be used for Panoramic radiographs.
  • A thyro-cervical shield must be used to protect the patient’s neck when its use does not interfere with the retrieval of diagnostic information. This shield must be provided for children when it will not interfere with the examination. A thyro- cervical shield is not recommended for Panoramic or CBCT radiographs.
  • Before any exposure is initiated the operator must ensure that the tube head has its proper and stable position.
  • Receptor holders with indicators for proper radiographic beam alignment are recommended for intraoral periapical and bitewing radiography.
  • Rectangular collimators must be used in combination with these receptor holders.
  • Retakes must be approved by a faculty supervisor and should be taken only for a valid clinical or diagnostic reason, not for the purpose of improving the esthetics of the radiograph.

B. Personnel Protection from Ionizing Radiation

  • Dental personnel must not directly hold an image receptor device in a patient’s mouth during radiography. If it is necessary to hold the receptor during an exposure, a mechanical holding device (example; RINN device) must be used.
  • Dental personnel must not hold patients during a radiographic exposure unless pre-approved in writing by the RSC for specified extreme conditions (such as patient management issues). The pre-approval must include precautions for maintaining radiation exposure to workers in compliance with ALARA standards and must include recording the information required in WAC 246-225A-020 su bsection (4)(b).
  • Dental personnel tasked with holding a patient or image receptor with mechanical supporting device must be protected with appropriate shielding or leaded protective devices (apron, gloves, and glasses) and must be monitored with a whole-body dosimeter and an extremity dosimeter. A single individual must not be used routinely as a holder. Any individual holding a patient or image receptorwith a mechanical supporting device must not be a pregnant person or under 18 years of age under any condition.

Personnel must return all dosimeters to EH&S Radiation Safety promptly after each wear period to maintain current and accurate occupational exposure records.

  • Holding research animals during a radiographic exposure is not allowed.
  • Any individual other than the patient must not be in the room or area while exposures are being made unless such individual’s assistance is required (e.g., parents, guardians, or dental personnel to hold the mechanical supporting device). If this is required, the individual must be protected with appropriate shielding or leaded protective devices and instructed to stay out of the primary beam path. The individual must not be a pregnant person or under 18 years of age under any condition.
  • All operators must stand behind a protective barrier, protected from the primary beam and not in the direction that the tube was pointed during each radiographic exposure.
  • Dental personnel must not hold the radiographic tube housing or the aiming cone (PID) during a radiographic exposure. If the tube support assembly is unstable and the tube drifts during exposure, the unit must be taken out of service and repaired.

C. Recording of Radiographic Procedures

All radiographic exposures, prescriptions, approvals, and interpretations must be recorded in the patient’s electronic health record promptly as described above in Radiographic equipment operator training, experience, and requirements. 

Research laboratories will retain the records of all research-related radiographic exposures, authorizations, and the research staff obtaining the radiographs.

Audits: At least once a year the Director of Oral Radiology, UWSOD, must audit randomly selected records of dental school patients and radiology processes as a component of an overall Continuous Quality Assessment cycle. These records are to be randomly generated by UWSOD Information Technology for this purpose. The audit will include prescription and recording of radiographic procedures, their approval and interpretation and retakes if any.

D. Facilities Management

EH&S Radiation Safety must be informed and be consulted when any radiographic units are relocated, disposed, purchased, or installed to ensure all regulatory requirements are met and registration by the Washington Department of Health can be updated.

The management of radiology equipment and facilities must be in compliance with state law and EH&S policy as described in Appendix B. Intraoral Dental Radiographic Unit Test and Technical Charts must be posted nearby to all radiographic units.

Routine maintenance and quality control testing of the CBCT machine must be performed according to manufacturer recommendations.

Viewing facilities:   It is each department’s responsibility to keep its radiographic viewing equipment and facilities in an adequate operating condition, as determined during EHS inspection.

E. Radiographic Image Quality Control

In an effort to maintain radiographic image quality at a high level, the dental clinician (including students, graduate students/residents, and faculty) must include in the patient’s EHR a critical review of every radiographic image quality with respect to projection, exposure, and possible processing errors or artifacts. When deficiencies are identified by the Director of Oral Radiology or the supervising faculty member, they must identify the source of the deficiency and implement remediation for the dental clinician, whether that clinician is faculty, staff, student, or graduate student/resident. Remedial measures may include reinforcement of instructions, individual tutorials, or other learning methods as appropriate to the identified deficiency and must include a post- remediation assessment to ensure that calibration has been achieved.

Audits: At least once a year the Director of Oral Radiology, UWSOD, must audit randomly selected records of dental school patients and radiology processes as a component of an overall Continuous Quality Assessment cycle. These records are to be randomly generated by UWSOD Information Technology for this purpose. The audit will include prescription and recording of radiographic procedures, their approval and interpretation, retakes if any, and image quality.

IV.  Image Archive and Interpretation Records 

All patient data and radiographic images shall be archived in axiUm and MiPACS as part of the patient’s medical records. CBCT volume records shall be stored in an accessible, secure hard drive. This includes all metadata such as patient health information (name, medical record number, date of birth, image acquisition parameters), name of the referring physician or prescribing dentist, date of the imaging, imaging modality, anatomical region of interest, and estimated radiation dose to the patient.

An official interpretation/report must be generated and archived in the patient record following the completion of any dental diagnostic imaging regardless of the modality (intraoral, panoramic, CBCT, etc.) and site/location where the images were captured.

The diagnostic imaging report must contain an “impression” or “conclusion” with relevant diagnoses and recommendations regarding the findings.

Only faculty and residents under faculty supervision should approve the final interpretation report. Non-faculty members, including radiation technicians, dental assistants, researchers, students, and others, should not approve the final interpretation report of an imaging examination or procedure. The final diagnostic imaging report should be completed in accordance with appropriate state and federal requirements as part of the patient’s medical record. The images and final report should be made available to the patient and other health care professionals when requested.

Reviewed February 23, 2021 by:

Head of Oral and Maxillofacial Radiology Division:

Peggy Lee, BDS, MSD, PhD, Director of Oral Radiology Clinic: Andrew Nalley, DDS

 Appendices:
Appendix A, Guidelines for Prescribing Dental Radiographs

Appendix B, Radiographic Equipment and Facility Management

Dean of UW SOD:

Andre Ritter, Dean of the UW School of Dentistry
November 17, 2023

Appendix A

Guidelines for prescribing dental radiographs

Modified after recommendations issued by U.S. Department of Health and Human Services, Public Health Service, Food & Drug Administration.  The recommendations in this chart are subject to clinical judgment and may not apply to every patient.  They are to be used by dentists only after reviewing the patient’s health history and completing a clinical examination.  The recommendations do not need to be altered because of pregnancy.

Adults

NEW PATIENT Recent radiographs (1-2 years old) of sufficient quality and quantity. low risk Bitewings
high risk PAN + bitewings
Previous radiographs >2 years old, or if more recent, of insufficient quality and/or quantity low risk PAN + bitewings
high risk FMS + bitewings (PAN)
No previous radiographs low risk PAN + bitewings
high risk FMS + bitewings (PAN)
RECALL PATIENT Use available previous radiographs low risk Bitewings 24-36 month interval
high risk Bitewings 12-18 month interval

Children and Adolescents

NEW PATIENT Primary Dentition bitewing if contacts closed
Transitional Dentition Panoramic radiograph + bitewings
RECALL PATIENT Bitewings 12–24-month interval Panoramic radiograph to assess 3rd molars and growth and development when needed.

Clinical situations for which radiographs may be indicated include:
Positive Historical Findings

  1. Previous periodontal or endodontic therapy
  2. History of pain or trauma
  3. Familial history of dental anomalies
  4. Post-operative evaluation of healing
  5. Presence of implants

Positive Clinical Signs/Symptoms

  1. Clinical evidence of periodontal disease
  2. Large or deep restorations
  3. Deep carious lesions
  4. Malposed or clinically impacted teeth
  5.  Swelling
  6. Evidence of facial trauma
  7. Mobility of teeth
  8. Fistula or sinus tract infection
  9. Clinically suspected sinus pathology
  10. Growth anomalies
  11. Unexplained bleeding
  12. Positive neurologic findings in the head and neck
  13. Evidence of foreign objects
  14. Unexplained sensitivity of teeth
  15. Facial asymmetry
  16. Abutment teeth for fixed or removable partial prosthesis
  17. Oral involvement in known or suspected systemic disease
  18. Pain and/or dysfunction of the temporomandibular joint
  19. Unusual eruption, spacing or migration of teeth
  20. Unusual tooth morphology, calcification or color
  21. Missing teeth with unknown reason

Patients at high risk for caries may demonstrate any of the following

  1. High level of caries experience
  2. History of recurrent caries
  3. Existing restoration of poor quality
  4. Poor oral hygiene
  5. Inadequate fluoride exposure
  6. Prolonged nursing (bottle or breast)
  7. Diet with high sucrose frequency
  8. Poor family dental health
  9. Developmental enamel defects
  10. Developmental disability
  11. Xerostomia
  12. Genetic abnormality of teeth
  13. Many multi-surface restorations
  14. Chemo/radiation therapy

Appendix B

Radiographic Equipment and Facility Management

Dental Radiographic Rooms

Dental radiographic rooms must be in compliance with Washington Administrative Code (WAC) 246-225A-050 (Dental Radiographic facility design). These regulations address items necessary for a proper evaluation of safety and shielding requirements. Please contact EH&S Radiation Safety for proper evaluation to ensure compliance for all dental radiographic equipment and facility design.

Submission of shielding calculations and floor plans to the State of Washington Department of Health (DOH) are not required unless a ring-detector type CT or medical radiographic system will be used for dental imaging. If this is required, contact EH&S Radiation Safety for confirmation of shielding calculations and submission of plans to DOH.

Dental Radiographic Equipment

Dental radiographic  equipment must be in compliance with WAC 246-225A-060 (General requirements for all dental Radiographic systems), WAC 246-225A- 070 (Special requirements for dental extra-oral radiography), WAC 246-225A-080 (Special requirements for dental intra-oral radiography), and WAC 246- 225A-085 (Hand–held radiographic system)

Please contact EH&S Radiation Safety regarding regulatory specifications for dental radiographic equipment.

Radiographic Quality Assurance

RQA entails a system of policies and procedures with the aim to ensure that the radiographic diagnostic facilities produce consistent high-quality images and minimizing the risks to patients and providers. The requirements in WAC 246-225A-090 (Radiographic image processing requirements) and WAC 246-225A-110 (Film Processing quality assurance) must be met when applicable.

Periodic Surveys and Inspections

  • Radiographic apparatus and related items
    All intraoral radiographic equipment are generally surveyed and tested annually by EH&S Radiation Safety and Scientific Instruments Division at the University of Washington.
    1. EH&S Radiation Safety will perform a general safety characteristics, the acceptance testing and quality control for dental imaging equipment in adherence to WAC 246-225A.
    2. The Scientific Instruments Division at the University of Washington will also perform similar survey or testing on all the dental imaging equipment.

This survey and test ensures that the dental radiographic imaging equipment is working properly, as exemplified by scientific and technical testing to confirm that the equipment is performing as per manufacturer’s specification and regulatory requirements.

  • Additionally, the State of Washington Department of Health will perform an announced inspection every 4 years for all dental imaging equipment.
  • EH&S Radiation Safety will also perform periodic audit (unannounced) of proper use of dental X ray equipment and adherence to radiation protection protocol, including but not limited to the use of collimators for intraoral radiographs and records of the exposure settings
  • Dose measurements
    Estimates of patient dose measurements are taken at the time of inspections by the Radiation Safety Office and Scientific Instruments staff. In addition, area measurements are made by Radiation Safety Office staff to evaluate exposure potential to operators and nearby personnel.