Radiation dosimetry under OSHA and NRC standards

September 19, 1995

Steven C. Collins, Chairman
Conference of Radiation Control Program Directors, Inc.
Division of Radioactive Materials
Department of Nuclear Safety
[Recipient address omitted]
Dear Mr. Collins:

This is in further response to your letter of September 8, 1994 concerning the revision of the Suggested State Regulations for Control of Radiation (SSRCR) proposed by the SR-2 Committee of the Conference of Radiation Control Program Directors, Inc. (CRCPD).

In that letter, you referenced revisions to 10 CFR Part 20 which you said became effective for U.S. Nuclear Regulatory Commission (NRC) licensees on January 1, 1994. You also stated that the SR-2 committee had proposed to revise the SSRCR to be more compatible with the revisions of 10 CFR Parts 19 and 20. One of the proposed recommendations from the SR-2 committee would be to use an "effective dose equivalent" (EDE) when workers were wearing shielding during medical fluoroscopic procedures. According to the literature you provided, the EDE would be calculated from either: 1) the measured readings, multiplied by a reduction factor, of a collar dosimeter alone, or; 2) the actual reading of one dosimeter placed under the shielding averaged with the measured reading, multiplied by a reduction factor, of another dosimeter placed on the collar. The rationale for using this system was that the worker would be wearing shielding over part of the body. Also, the article attached to your letter from the Health Physics Newsletter (May 1994) expressed concerns that a potential problem could be created for physicians and other workers who perform special fluoroscopic x-ray procedures should they exceed their annual dosage limits for radiation and not be allowed to use the accumulated occupational dose limit because it was deleted from the NRC regulations.

In answering your questions, please be aware that the Occupational Safety and Health Administration's (OSHA) Ionizing Radiation Standard, 29 CFR 1910.96 [1910.1096] has not been revised, and the accumulated occupational dose limit [5(N-18) rems] has not been eliminated from the OSHA standard. Therefore, no new regulatory requirement has been created with respect to the community covered by the OSHA standard for ionizing radiation, and we are not aware of any specific problems with employers complying with that standard. Should specific problems arise, these could be addressed on an individual basis.

The OSHA Ionizing Radiation standard requires that, for determining exposure to x-rays, the dose must be measured at or near the body surface in the region of the highest dosage rate. Dose to the whole body shall be deemed to include any dose to the whole body, gonad, active blood forming organs, head and trunk, or lens of the eye. The effective dose equivalent (EDE) proposed by the SR-2 Committee appears to differ from the OSHA monitoring requirements for ionizing radiation. Therefore, it should be mentioned that in situations where employers are using methods that differ from those prescribed by OSHA, but that the employer believes are equal to or better than OSHA's requirements, the employer must be able to show that his or her facility or method of operation provides employee protection at least as effective as that required by OSHA's standards.

Thank you for your inquiry. We hope this information has been helpful in addressing your concerns. If you have any further questions, please contact [the Office of Health Enforcement at (202) 693-2190].

Sincerely,

John B. Miles, Jr., Director
Directorate of Compliance Programs

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[Corrected 12/6/2024]