Radiation badges and shielding

In recent months, the MDA has received inquiries about the necessity of dental team members to wear radiation badges (dosimeters). John Langston has provided this update to the MDA, and provided an update on Radiation Safety Inspections in the last issue of the Focus. John is the Bureau Administra- tor, Ambulatory Care, Missouri Department of Health and Senior Services, of which the Missouri Radiation Control Program is part. Here, he answers two related questions: Do dental facilities need to provide staff with radiation badges; and, does dental x-ray require radiation shielding in the walls?

DO DENTAL FACILITIES NEED TO PROVIDE STAFF WITH RADIATION BADGES?

Is radiation monitoring required for dental facilities? Accurately answering that question depends on a number of factors that are different for each facility, but for most dental facilities, individual personnel monitoring would not be required.

There are overlapping standards for radiation protection. In general, dental facilities that use x-ray machines must comply with both Missouri Radiation Control Program (MRCP) rules (19 CSR 20-10.010—10.200) as well as OSHA requirements (Standard 1910.1096). For some facilities, there may be additional standards required by accreditation organiza- tions or insurance companies that must also be met.

Note: Throughout this document radiation unit measurements are commonly described in mR (millirem) as in the existing state regulations. The conversion between millirem (mR) and mil- liSievert (mSv) is 1 mSv = 100 mR.

Missouri Radiation Control Program Rule 19 CSR 20-10.050 Personnel Monitoring and Radiation Surveys

“(3) Personnel monitoring shall be required for each individual for whom there is any reason- able possibility of receiving a weekly dose of all radiation exceeding fifty (50) millirems, taking into consideration the use of protective gloves, aprons or other radiation-limiting devices.”

“(4) Routine monitoring of individuals occu- pationally exposed to radiation from radiation machines shall not be required if—A qualified expert has specified the operating conditions under which there is no reasonable chance that any individual will be subjected to a dose of either more than twenty-five (25) millirems in any seven (7) consecutive days.”

OSHA Standard 1910.1096(d)(2),(i) “Every employer shall supply appropriate

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personnel monitoring equipment…, and shall require the use of such equipment by…each employee [18 or older] who enters a restricted area [any part of the facility] under such circumstances that he receives, or is likely to receive, a dose…excess of [25 mR per week, (25% of the quarterly limit of 1250 mR.)]”

The National Council of Radiation Protec- tion (NCRP), in NCRP Report #145 “Radia- tion Protection in Dentistry,” recommends a conservative standard of monitoring all personnel who are likely exposed to 100 mR/ year (2 mR/week). However, NCRP also notes that even this conservative standard is a level that most dental operators won’t reach. “The majority of dental workers would not be expected to require individual monitoring.” (NCRP 145, page 70.) Also note that NCRP #145 was written in 2004, before there were as many digital dental x-ray units in place that (in some cases) have reduced exposures significantly.

Assuming safe radiation safety procedures are used, most dental operators are not exposed to even the conservative 2 mR/week, and certainly not the regulatory limit of 25 mR/week or more. (Safe procedures would

include operator training in radiation safety; ensuring that operators do not hold the head of the dental unit while making exposures; operators stepping out of the operatory at least six feet (6’) from the tube head to a protected/shielded location while making the exposure; while in use the dental unit is not pointed directly toward anyone other than the patient, etc.)

So if most facilities would not be required to provide monitoring, how can a facility deter- mine whether they are one of the minority where monitoring would be required?

Probably the best option is to consult with an approved Qualified Expert (QE) in radia- tion safety with any questions you may have about monitoring. All new dental facilities opening (or adding additional x-ray rooms) after January 1, 2014 are required to contact a QE for a radiation safety inspection. Existing dental facilities will need to arrange to have a safety inspection by a QE between 2017 and 2022, and periodically thereafter (sooner if you move practice locations or add new rooms). A QE can give your facility person-