X-Ray standard operating procedures

Registrants seeking to purchase or acquire x-ray equipment must either purchase this equipment using the university purchasing codes below, or contact Environmental Health and Safety (EHS) for guidance before proceeding. Registration for all analytical x-ray equipment must be kept on file with EHS. They will register the equipment with Arizona Radiation Regulatory Agency (AZRRA). The registrant must be a full time faculty, academic professional, or NAU staff member who bears overall responsibility for safe use of registered equipment. New equipment must be registered prior to operation.

Codes for ordering X-Ray equipment:

• 89800 X-Ray/Radiological Equipment (Not Dental) Non Capital <$5K
• 8968 X-Ray and Radiological Equipment (Recycled)
• 89880 X-Ray/Radiological Equipment (Except Dental) Capital >$5K
• 89899 X-Ray/Radiological Supplies

All analytical x-ray equipment must be registered with EHS who in turn maintains the required device registrations with AZRRA. All analytical x-ray equipment must be registered to a faculty, academic professional, or staff member of NAU who maintains responsibility for all aspects of safety for the registered equipment. Specific responsibilities of the registrant include:

1. Registration of new equipment with the Radiation Safety Officer/EHS within 30 days of receipt and prior to operation.
2. Ensuring that operators are properly trained and made aware of hazards associated with the equipment prior to operation of the equipment. Required training may require EH&S administered online or in person training for x-ray devices as well as lab specific training administered by the registrant.

Analytical x-ray equipment is registered by contacting the Radiation Safety Officer or Environmental Health and Safety, who will schedule a site inspection/consultation before filing the required equipment registration with AZRRA. Registration shall be completed within 30 days of receipt of new equipment or reconfiguration of existing equipment, and prior to operation of the equipment.

Additional details on x-ray equipment safety may be found in the NAU X Ray Manual.

EHS offers online X-ray Safety Training which is mandatory for all authorized equipment operators. The training is covers basic safety issues which are consistent with all x-ray equipment. It is intended to be complemented with equipment or site specific training which is performed by the registrant for all authorized users on his/her equipment.

Operators must receive training in the following topics:

1. Types and amounts of radiation to which workers could be exposed
2. Health effects of exposure to low doses of ionizing radiation
3. Precautions and procedures to minimize exposure to ionizing radiation
4. Applicable provisions of AZRRA and NAU rules and regulations
5. Responsibilities of personnel using radiation producing equipment including the need to bring violations of AZRRA and NAU rules and regulations to the attention of EHS
6. Response in the event of exposures to radiation and other emergencies
7. Rights of workers to have access to radiation exposure records
8. Correct procedures for safe and effective operation of the analytical x-ray equipment.

In instances which operators may be partially or completely within the regulated area during operation or maintenance of x-ray equipment (IE no shielding between equipment and operator), exposure monitoring may be required. Determination of the need for exposure monitoring will be made by the Radiation Safety Officer (RSO) at the time of the initial registration, during consultation for changes to device or safety equipment configuration, or during periodic audits.

TLD badges are used at the university to monitor personnel for exposure of the body to penetrating ionizing radiation such as gamma and x-rays, and exposure of the skin to less penetrating radiation such as beta particles. For most individuals, results of the TLD badge readings are also used as estimates for the exposure of the lens of the eye. TLD badges are required for operators of most analytical x-ray equipment at the university. They are not required for some cabinet type equipment.

TLD badges must be worn on the trunk of the body at or above the waist. Dosimetry devices must not be taken home or left in laboratory areas where they may be exposed to radiation or excessive heat or humidity.

Ring dosimetry devices are used to monitor for radiation exposure to the hands and are issued to most personnel using analytical x-ray equipment. Ring badges must be worn with the sensitive portion of the ring towards the source.

TLD badges and rings are exchanged on a quarterly basis. EHS personnel hand deliver badges and rings to department offices during the last few days of each quarter. Used dosimetry devices must be picked up by, or hand delivered to EHS. Dosimetry devices should be returned to EHS during the first five (5) working days of the new quarter. Campus mail must not be used. This policy has been established to avoid exposure of TLDs and rings to sources of radiation, heat, and humidity during transit and maintain the chain of custody.

Periodically, dosimetry devices are lost or damaged. This should be reported to EHS staff immediately so that replacement dosimeters can be issued.

After initial installation and upon completion of alterations or maintenance, EHS must conduct a survey for radiation leakage before the unit is placed in service. Surveys may be scheduled through the RSO or EHS.

Only maintenance personnel with adequate training to perform the task may install, repair, or make other than routine changes to the x-ray generating apparatus and the tube housing apparatus.

Safety interlocks and other safety devices will be tested semi-annually by registrants. Records of these tests should be kept with the equipment by the registrant for review by Office of Radiation Safety or AZRRA personnel. Access the Device Interlock Inspections Forms Semi-Annual Device Interlock Inspection Checklist.

AZRRA has imposed limits on the dose of ionizing radiation which may be received by individuals working with sources of ionizing radiation. These limits are shown in Table 4-1.

Annual Limit, whichever is the more limiting between:

1. Total Effective Dose Equivalent
2. Sum of the deep dose equivalent and committed dose equivalent to any organ or tissue other than the lens of the eye

(Create Table) Table 4-1 Regulatory Dose Limits

Annual Limit, which is the more limiting of:

a. Total Effective Dose Equivalent – 5 rem (0.05 Sv)

b. Sum of the deep dose equivalent and committed dose equivalent to any organ or tissue other than the lens of the eye – 50 rem (0.5 Sv)

Eye Dose Equivalent
15 rem (0.15 Sv)

Shallow Dose Equivalent to the skin or to each of the extremities
50 rem (0.5 Sv)

Limits to the Embryo-Fetus of Declared Pregnant Workers

Due to concerns about prenatal radiation exposure (See Appendix A of the X-Ray Program Manual) AZRRA regulations provide separate limits for the embryo/fetus of Declared Pregnant Workers. The limit is 0.5 rem dose equivalent to the fetus during pregnancy. This limit applies only for workers who have formally declared pregnancy. In addition to other recipients, declaration of pregnancy should be sent to the Radiation Safety Officer and include the estimated date of conception.

Individuals concerned about radiation and pregnancy should feel free to speak to the Radiation Safety Officer.

Limits for Members of the Public

The regulatory limit for members of the public is 0.1 rem total effective dose equivalent per year. This limit applies to all individuals who are not trained to work with sources of ionizing radiation. At NAU this includes most faculty, staff and students.

Investigation Levels

Investigational levels have been established at NAU. These dose levels are shown in Table 4-2.

Personnel exposures equal to or greater than investigational Level I (based on dosimetry results) are reviewed by the RSO, who reports the results to the RSC at their next regularly scheduled meeting. The RSC may require corrective actions on the part of the RSO or registrant.

Personnel exposures equal to or exceeding Investigational Level II are investigated in a timely manner by the RSO who takes immediate action if warranted. A report of the investigation, actions taken, and a copy of the individual’s radiation dosimetry history is included in that individuals records, and a report with personal data redacted may be presented to the RSC at their next scheduled meeting following completion of the investigation. The RSC may impose restrictions on future use as warranted.

Investigational limits exceeding those listed in Table 4-2 may be established by the RSC for a worker or group of workers when the higher investigational levels are consistent with good ALARA practice for the work being conducted by the individual or group.

Create Table

Table 4-2 Investigational Dose Levels

Limit
Level (rem/quarter)

Level I Level II
Total Effective Dose Equivalent
0.065 0.200
Eye Dose Equivalent
0.180 0.600
Shallow Dose Equivalent to the Skin or to each of the Extremities
0.625 2.000

Other Radiation Limits

a. Each x-ray tube housing must be so constructed that with all shutters closed the leakage radiation measured at a distance of 5 cm from its surface is not capable of producing a dose in excess of 2.5 mrem in one hour at any specified tube rating.

b. Each x-ray generating device must be supplied with a protective cabinet which limits leakage radiation measured at a distance of 5 cm from its surface such that it is not capable of producing a dose in excess of 0.25 mrem in one hour.

c. Any apparatus utilized in beam alignment procedures must be designed in such a way that excessive radiation will not strike the operator. Particular attention should be given to viewing devices, in order to ascertain that lenses and other transparent components attenuate the beam to an acceptable level.

Written emergency procedures pertaining to radiation safety shall be established for each x-ray producing apparatus. Emergency Procedures must be approved by the Radiation Safety Officer and posted in a conspicuous location. These procedures shall list the telephone number(s) of the Radiation Safety Officer, telephone number of the responsible registrant for that equipment, and at a minimum include the following actions to be taken in case of a known, or suspected accident involving radiation exposure:

a. Notify the Radiation Safety Officer, and

b. Arrange for medical examination.

In the event of a known or suspected accidental exposure exceeding established exposure limits, operators must immediately follow the posted emergency procedures. If medical attention or treatment is required, arrangements for medical intervention shall be made first. Notifications to the Radiation Safety Officer and Registrant may be made once the medical needs of the exposed party are met.