Answer to Question #10784 Submitted to "Ask the Experts"
Category: Medical and Dental Equipment and Shielding — Shielding
The following question was answered by an expert in the appropriate field:
What are the health risks to the x-ray operator when using handheld dental x-ray imaging equipment?
The health risks associated with the operation of handheld dental units are the same risks that can be associated with the operation of any x-ray equipment and/or working with radioactive materials. These can be found in a variety of publications such as radiobiology or health physics/medical physics textbooks. Another publication that addresses the risks of working with radiation as an occupationally exposed worker is Regulatory Guide 8-29, "Instruction Concerning Risks From Occupational Radiation Exposure," published by the US Nuclear Regulatory Commission. Although this document is published for use with radioactive materials, the health risks also apply to use with x rays.
Since working with radiation in a safe manner reduces the risk of effects for the radiation worker to acceptable levels, the more important question to ask is, "What can be done to minimize radiation dose to the person operating a handheld dental unit?" One way is to utilize properly designed handheld units such as those noted in the American Dental Association (ADA) and the US Food and Drug Administration (FDA) document "Dental Radiographic Examinations: Recommendations for Patient Selection and Limiting Radiation Exposure." This document reads in part, "Handheld, battery-powered x-ray systems are available for intraoral radiographic imaging. The handheld exposure device is activated by a trigger on the handle of the device. However, dosimetry studies indicate that these handheld devices present no greater radiation risk than standard dental radiographic units to the patient or the operator. No additional radiation protection precautions are needed when the device is used according to manufacturer's instructions." These handheld devices operated by a trigger on the handle should not be confused with camera-like devices operated by a pushbutton. For protection when using the pushbutton type of devices, one might refer to a rule from the state of Ohio (in addition to other dental rules, the following additional requirements are specific to handheld x ray):
- Handheld radiation-generating equipment shall be used for intraoral purposes only.
- Operators of the handheld radiation-generating equipment shall wear a full lead apron of not less than 0.25 millimeter lead equivalent.
- The backscatter shield for the handheld radiation-generating equipment shall be in place during all radiographic exposures (if the device was designed with a backscatter shield).
- Storage and security procedures shall be developed and implemented to assure handheld radiation-generating equipment is secured against unauthorized use or removal when not under the control and constant surveillance of the registrant.
- Operator training shall include documented specific instruction to the x-ray operator regarding the prohibition on placing any part of their body into the useful beam and ensuring there are no bystanders within a radius of at least six feet from the patient being examined during exposure.
Following good radiation safety practices in the form of training and safe operating procedures will minimize radiation dose to workers and, in turn, will minimize the possibility of radiation effects.
Edgar D. Bailey, PE, CHP
Kennith Lovins, CHP
References:
US Nuclear Regulatory Commission
American Dental Association and US Food and Drug Administration
Ohio Department of Health, Ohio Administrative Code OAC 3701:1-66-06