Radiation Safety Policy

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

Purpose

This policy establishes mandatory protocols and procedures designed to:

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

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 other individuals who are responsible for the proper use and maintenance of radiation equipment and supplies (including film, darkrooms, and processors). 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 the UW School of Dentistry (SOD) entitled, Hazard Control in the Dental Environment, shall be utilized in all SOD clinics where such services are rendered.

Implementation

I. General Radiation Safety Issues

A. Compliance Statement

The policies, procedures, and criteria outlined herein 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 Section of the Department of Environmental Health and Safety (EH&S) of the University of Washington (UW). Compliance with this policy is the obligation of all members of the SOD workforce. The policy applies to faculty, students, clinical staff, volunteers, residents, and other individuals who are responsible for the proper use and maintenance of radiation equipment and supplies (including film, darkrooms and processors) involved in diagnostic radiology.

SOD members must:

Adhere to accepted protocols for the safe operation of radiologic equipment for their own protection and for the protection their patients.
Follow sound and logical radiological health practices and report any suspected health hazards to the SOD Department of Radiology and to the UW Radiation Safety Committee (RSC).
Adhere to the infection control policy of the school during radiographic procedures.
Consult with the SOD 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. Annual inspections are performed including but not limited to:

Measurements of radiation in controlled and non-controlled areas.
Performance testing of x-ray 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 SOD Department of Radiology division shall serve on the UW RSC, act as a liaison between individual SOD users of radiation and the RSC, and assist EH&S Radiation Safety in the implementation of the SOD Radiation Safety Policy. This position will help to develop radiation safety training that includes ALARA principles, radiographic procedures, safe operation of each type of dental x-ray 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. X-ray equipment operator training and experience

Any new SOD workforce member who may be operating x-ray equipment will be required to complete radiation safety training as part of the onboarding process. All operators of x-ray equipment are required to complete radiation safety training and equipment specific training prior to operating x-ray equipment and annually thereafter.

The use of diagnostic x-ray equipment in the practice of dentistry at the SOD shall be restricted to those individuals described in this section.

Predoctoral Students: The operation of x-ray equipment by predoctoral students is authorized but limited to the following restrictions:

The operator shall have didactic and preclinical training and a passing grade in oral radiology.
The student is current with annual radiation safety training
All x-ray exposures must be justified in relation to their benefits, sufficient clinical information and the rational of the prescription of x-ray radiograph should be recorded in Axium.
The x-ray exposures shall be authorized by a clinical attending (faculty or instructor) of the SOD as evidenced by the signature on the prescription. 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 Axium record for images taken in any other clinic.
The prescribing faculty or instructor shall approve the quality of the radiograph(s) as evidenced by the faculty or instructor’s digital approval on the record.
The Axium record will document radiographic interpretation.

Graduate Students: The operation of x-ray equipment by graduate students without a current valid Washington license is authorized but limited to the following restrictions:

The operator shall possess a dental degree and be current with annual radiation safety training.
The student is current with annual radiation safety training
The x-ray exposures shall be authorized by faculty of the School of Dentistry as evidenced by the signature on the prescription, except licensed graduate students with waivers from a faculty. 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 Axium record for when images are taken in a graduate clinic.
The prescribing dentist shall approve the quality of the radiograph(s) as evidenced by the digital approval on the record.
The Axium record will document radiographic interpretation.

Radiology Technicians and dental assistants: The operation of x-ray equipment by SOD radiology technicians and dental assistants is authorized but limited to:

The x-ray operator shall have adequate training in radiographic techniques and be current with annual radiation safety training
The x-ray exposure shall be authorized by a member of the faculty of the SOD as evidenced by the faculty member’s signature or digital approval.
A member of the faculty should be available for consultation when required.
The prescribing faculty or instructor shall approve the quality of the radiograph(s) as evidenced by the instructor’s digital approval of the MiPACS images.

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

Researchers: The operation of x-ray equipment for research is authorized but limited to:

The x-ray operator shall have adequate training in radiographic techniques and be current with annual radiation safety training
The x-ray exposure shall be authorized by a member of the faculty of the SOD as evidenced by the faculty member’s signature or digital approval.
A member of the faculty should 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 should voluntarily declare her pregnancy in writing to her employer and include her 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 an x-ray 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 from working in occupations involving potential exposure to radioactive substances and to ionizing radiation. Therefore minors working in the SOD shall not be permitted to operate x-ray equipment or work near an x-ray equipment during operation.

Any individual monitoring device used for monitoring the dose to the whole body shall 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 shall 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 woman shall be located at the waist under any protective apron being worn by the woman.

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 shall be no “routine” radiographic examinations. Radiographic examinations shall be carried out solely based on clinical indications. Radiographs shall 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 x-ray equipment operator shall 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 is recommended to shield the trunk of the body and the gonads of the patient. The lead equivalent of the apron should be at least 0.25 mm.
A thyro-cervical shield is recommended to protect the patient’s neck when the use of it does not interfere with the retrieval of diagnostic information. This shield shall 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 shall ensure that the tube head has its proper and stable position.
Receptor holders with indicators for proper x-ray beam alignment are recommended for intraoral periapical and bitewing radiography. Rectangular collimators are recommended in combination with these receptor holders.
Retakes should 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 shall not directly hold an x-ray film or image receptor device in a patient’s mouth during radiography. If it is necessary to hold the receptor during an exposure, mechanical holding devices (example; RINN device) must be used.
Holding patients during an x-ray exposure shall also be avoided unless approved by the RSC and under extreme conditions. Holding a patient during x-ray exposure is only allowed under certain conditions (such as patient management issues) as specified in pre-approved written procedures. The procedure 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 subsection (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 shall be used routinely as a holder. Additionally, an individual holding a patient or image receptor with mechanical supporting device must not be a pregnant women or under 18 years of age under any condition.
All dosimeters must be return to EH&S Radiation Safety promptly after each wear period to maintain current and accurate occupational exposure records.
Holding research animals during an x-ray exposure is not allowed.
No individual other than the patient shall 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 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 shall not be pregnant women or under 18 years of age under any condition.
All operators shall stand behind a protective barrier, protected from the primary beam and not in the direction that the tube was pointed during each x-ray exposure.
Dental personnel shall not hold the x-ray tube housing or the aiming cone (PID) during an x-ray exposure. If the tube support assembly is unstable and the tube drifts during exposure, the unit shall be taken out of service and repaired.

C. Recording of Radiographic Procedures

Axium will hold a record of radiographic exposures, prescriptions, approval, and interpretation. Bi-annual auditing will be performed to review the prescription and approval of images. Research lab books will contain the record of research-related radiographic exposures and the research staff obtaining the radiographs.

D. Facilities Management

EH&S Radiation Safety must be informed and be consulted when x-ray units are relocated, disposed, purchased, or installed so that the regulatory requirements are met and the x-ray registration by the DOH can be updated.

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

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

Viewing facilities: It is the responsibility of each department to keep viewing equipment and facilities in an adequate operating condition.

E. Radiographic Image Quality Control

In an effort to maintain radiographic image quality at a high level, each radiographic examination shall include a critical review of image quality with respect to projection, exposure, and possible processing errors or artifacts. Remedial measures such as reinforcement of instructions, individual tutorials, etc., should be employed.

Audits: At least once a year randomly selected records of dental school patients and radiology processes shall be generated by SOD IT for review by the Director of Oral Radiology, School of Dentistry with regard to prescription and recording of radiographic procedures, interpretation of radiographs, and image quality.

IV. Radiographic Duplication

Access to a duplicate of radiographs is a legal right of each patient of record. Patients, or their designated representatives may obtain such duplicates using the protocol in the Patient Records policy.

Appendices:
Appendix A, Guidelines for Prescribing Dental Radiographs

Appendix B, Radiographic Equipment and Facility Management

Dean of UW SOD:

Gary Chiodo, Dean of the UW School of Dentistry
March 3, 2021

Head of Oral and Maxillofacial Radiology Division:

Peggy Lee, BDS, MSD, PhD

Director of Oral Radiology Clinic:

Andrew Nalley, DDS

February 23, 2021

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	Radiographs of recent date (1-2 years old) of sufficient quality and quantity.	low risk	bitewing
		high risk	PAN + bitewing
	Previous radiographs more than 2 years old or more recent, of insufficient quality and quantity	low risk	PAN + bitewing
		high risk	FMS + bitewing (PAN)
	No previous radiographs	low risk	PAN + bitewing
	No previous radiographs	high risk	FMS + bitewing (PAN)

RECALL PATIENT	Use available previous radiographs	low risk	bitewing 24-36 month interval
		high risk	bitewing 12-18 month interval

Children and Adolescents

NEW PATIENT	Primary Dentition	bitewing if contacts closed
NEW PATIENT	Transitional Dentition	PAN + bitewing

RECALL PATIENT

bitewing 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

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

Positive Clinical Signs/Symptoms

Clinical evidence of periodontal disease
Large or deep restorations.
Deep carious lesions
Malposed or clinically impacted teeth.
Swelling.
Evidence of facial trauma.
Mobility of teeth.
Fistula or sinus tract infection.
Clinically suspected sinus pathology.
Growth anomalies.
Unexplained bleeding.
Positive neurologic findings in the head and neck.
Evidence of foreign objects.
Unexplained sensitivity of teeth.
Facial asymmetry.
Abutment teeth for fixed or removable partial prosthesis.
Oral involvement in known or suspected systemic disease.
Pain and/or dysfunction of the temporomandibular joint.
Unusual eruption, spacing or migration of teeth.
Unusual tooth morphology, calcification or color.
Missing teeth with unknown reason.

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

High level of caries experience
History of recurrent caries
Existing restoration of poor quality.
Poor oral hygiene.
Inadequate fluoride exposure.
Prolonged nursing (bottle or breast).
Diet with high sucrose frequency.
Poor family dental health.
Developmental enamel defects.
Developmental disability.
Xerostomia.
Genetic abnormality of teeth.
Many multi-surface restorations.
Chemo/radiation therapy.

Appendix B

Radiographic Equipment and Facility Management

Dental x‑ray rooms

Dental x‑ray rooms are to be in compliance with Washington Administrative Code (WAC) 246‑225A‑050 (Dental X-ray 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 x-ray 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 x-ray 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 x‑ray equipment

Dental x‑ray equipment is to be in compliance with WAC 246-225A-060 (General requirements for all dental X-ray 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 X-ray system)

Please contact EH&S Radiation Safety regarding regulatory specifications for dental X-ray 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 (X-ray image processing requirements) and WAC 246-225A-110 (Film Processing quality assurance) must be met when applicable.

Periodic surveys and inspections

x‑ray apparatus and related items
All intraoral x‑ray equipment are generally survey 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 x-ray 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.