Answer to Question #2983 Submitted to "Ask the Experts"

Since I am not familiar with you, your office, and the office with the fluoroscopy, I have a difficult time evaluating your comments indicating that the office next door is operating without any approved shielding recommendations or surveys.

I can tell you that the accepted process in most states is for the facility, which in this case is the physician, to register with the state in order to possess and use x-ray equipment. Typically, a c-arm fluoroscopy unit, like the ones used for epidural pain procedures, is mobile and shielding is not required when that unit remains truly mobile, that is, it is used in a number of rooms. Many times with facilities like you describe, the unit stays in one room for its use. In this case a shielding evaluation by a Qualified Radiation Expert is typically required by the state, since it is essentially a "fixed" unit.

Shielding recommendations are based on a number of items such as the following: (1) workload, that is, the average time the fluoroscopy radiation beam is actually on per week, (2) the distance to the areas in question, for example, distance you are from the x-ray unit when it is operating, (3) occupancy of adjacent areas, that is, if you are at a desk full-time, the occupancy is 1, instead of some fraction, (4) whether the persons in adjacent areas are occupationally exposed or nonoccupationally exposed, for example, you would be considered a nonoccupational worker since you work in a different office, and (5) the maximum energy of the x-ray beam. Since I have no data for the actual use of this unit, for example, the number of patients per week and average amount of fluoroscopy "on" time, I cannot tell you if lead is needed in the walls of the treatment room.

Also, when a vendor installs a piece of x-ray equipment, there is a Food and Drug Administration form that must be completed indicating the installation. Copies of this form are given to the purchaser and to the state regulatory agency. If this unit was purchased through normal channels, then the state you are in should have a copy of this form. If they do not have record of that facility being registered, they should contact the facility and make them aware of the requirements.

After the unit is in place, a Qualified Radiation Expert should make a survey of all surrounding areas to determine if shielding in place is adequate. Please note that some installations may not require any shielding based on the amount of use of the unit. If the facility next to you has not been shielded, but a survey has shown that measured radiation dose rates are acceptable in adjacent areas, then your risk is low. If there has been no shielding plan and no survey and the individual operating the unit is not registered with the state, your risk may be measurably higher. However, without any evaluation, the question cannot be answered. If this has been going on for a short time, you should not be too concerned.

If you do believe in your assertions regarding inadequate protect, I recommend that you have your supervisor or physician contact the physician next door and discuss your concerns. If this does not resolve the issue, and you have good reason to believe that the adjacent office is performing x-ray procedures without state approval, shielding plan review, or surveys, you are entitled to call the state radiation control branch and voice your concerns.

Ken "Duke" Lovins, CHP

Editor’s Note: A list of state radiation regulatory agencies can be found at the Conference of Radiation Control Program Directors’ Web site.