| (v) If multiple measurements have not been made, assignment of the highest DDE for the declared pregnant woman shall be the DE to the embryo/fetus. (2) The assigned DDE shall be for the portion of the body receiving the highest exposure. The assigned SDE shall be the dose averaged over the contiguous 10 square centimeters of skin receiving the highest exposure. (3) When a protective apron is worn while working with fluoroscopic equipment used for clinical diagnostic or research purposes, the effective dose equivalent (EDE) for external radiation shall be determined as follows. (A) When only 1 individual monitoring device is used and it is located at the neck (collar) outside the protective apron, the reported DDE shall be the EDE for external radiation; or (B) When only 1 individual monitoring device is used and it is located at the neck (collar) outside the protective apron, and the reported dose exceeds 25% of the limit specified in paragraph (1) of this subsection, the reported DDE value multiplied by 0.3 shall be the EDE for external radiation; or (C) When individual monitoring devices are worn, both under the protective apron at the waist and outside the protective apron at the neck (collar), the EDE for external radiation shall be assigned the value of the sum of the DDE reported for the individual monitoring device located at the waist under the protective apron multiplied by 1.5 and the DDE reported for the individual monitoring device located at the neck (collar) outside the protective apron multiplied by 0.04. (4) The EDE determined by paragraph (3) of this subsection shall be recorded as part of an individual's dose record and will contribute to that individual's annual TEDE. (5) The DDE, LDE, and SDE may be assessed from surveys or radiation measurements for the purpose of demonstrating compliance with the occupational dose limits, if the individual monitoring device was not in the region of highest potential exposure, or the results of individual monitoring are unavailable. (6) The registrant shall reduce the dose that an individual may be allowed to receive in the current year by the amount of occupational dose received from radiation machines or radioactive materials while employed by any other person. See subsection (r)(4) of this section. (n) Conditions requiring individual monitoring of occupational dose. (1) Each registrant shall monitor exposures from radiation machines at levels sufficient to demonstrate compliance with the occupational dose limits of this section. As a minimum, each registrant shall monitor occupational exposure to radiation from radiation machines and shall supply and require the use of individual monitoring devices by: (A) adults likely to receive, in 1 year from sources external to the body, a dose in excess of 10% of the limits in subsection (m)(1) of this section; (B) minors likely to receive, in 1 year from sources of radiation external to the body, a DDE in excess of 0.1 rem (1 mSv), an LDE in excess of 0.15 rem (1.5 mSv), or an SDE to the skin or to the extremities in excess of 0.5 rem (5 mSv); (C) declared pregnant women likely to receive during the entire pregnancy, from sources of radiation external to the body, a DDE in excess of 0.1 rem (1 mSv); and (D) individuals entering a high or very high radiation area. (2) Notwithstanding the requirements of paragraph (1)(A) of this subsection, no personnel monitoring shall be required for personnel operating only minimal threat radiation machines as specified in subsection (ll)(3) of this section. (o) Dose limits for individual members of the public. (1) Each registrant shall conduct operations so that: (A) the TEDE to individual members of the public from exposure to radiation from radiation machines does not exceed 0.5 rem (5 mSv) in a year, exclusive of the dose contribution from background radiation, exposure of patients to radiation for the purpose of medical diagnosis or therapy, or to voluntary participation in medical research programs; and (B) the dose in any unrestricted area from registered external sources does not exceed 0.002 rem (0.02 mSv) in any 1 hour. (2) If the registrant permits members of the public to have access to restricted areas, the limits for members of the public continue to apply to those individuals. (3) The agency may impose additional restrictions on radiation levels in unrestricted areas in order to restrict the collective dose. (4) The registrant shall ensure that in facilities utilizing both radiation producing machines and radioactive materials, the TEDE to an individual member of the public shall not exceed 0.1 rem (1 mSv) in 1 year. (p) Compliance with dose limits for individual members of the public. (1) The registrant shall make or cause to be made surveys of radiation levels in unrestricted areas to demonstrate compliance with the dose limits for individual members of the public as required in subsection (o) of this section. (2) A registrant shall show compliance with the annual dose limit in subsection (o) of this section by demonstrating by measurement or calculation that the TEDE to the individual likely to receive the highest dose from the registered operation does not exceed the annual dose limit. (3) Registrants exempt from individual monitoring requirements in accordance with subsection (n)(2) of this section are exempt from the requirements of paragraphs (1) and (2) of this subsection. (q) Location and use of individual monitoring devices. (1) Each registrant shall ensure that individuals who are required to monitor occupational doses in accordance with subsection (n)(l) of this section wear and use individual monitoring devices as follows. (A) An individual monitoring device shall be assigned to and worn by only one individual. (B) An individual monitoring device used for monitoring the dose to the whole body shall be worn at the unshielded location of the whole body likely to receive the highest exposure. When a protective apron is worn, the location of the individual monitoring device is typically at the neck (collar). (C) If an additional individual monitoring device is used for monitoring the dose to an embryo/fetus of a declared pregnant woman, in accordance with subsection (n)(1)(C) of this section, it shall be located at the waist under any protective apron being worn by the woman. (D) An individual monitoring device used for monitoring the LDE, to demonstrate compliance with subsection (m)(1)(B)(i) of this section, shall be located at the neck (collar) or at a location closer to the eye, outside any protective apron being worn by the monitored individual. (E) An individual monitoring device used for monitoring the dose to the extremities, to demonstrate compliance with subsection (m)(1)(B)(ii) of this section, shall be worn on the extremity likely to receive the highest exposure. Each individual monitoring device, to the extent practicable, shall be oriented to measure the highest dose to the extremity being monitored. (2) Each registrant shall ensure that individual monitoring devices are returned to the dosimetry processor for proper processing. (3) Each registrant shall ensure that adequate precautions are taken to prevent a deceptive exposure of an individual monitoring device. (r) Determination of occupational dose for the current year. (1) For each individual who is likely to receive, in a year, an occupational dose requiring monitoring in accordance with subsection (n) of this section, the registrant shall determine the occupational radiation dose received during the current year. Occupational dose includes doses received from exposure to registered/licensed or unregistered/unlicensed sources of radiation as defined in subsection (c) of this section. (2) In complying with the requirements of paragraph (1) of this subsection, a registrant may: (A) accept, as a record of the occupational dose that the individual received during the current year, RC Form 231-3 from prior or other current employers, or other clear and legible record, of all information required on that form and indicating any periods of time for which data are not available; or (B) accept, as a record of the occupational dose that the individual received during the current year, a written signed statement from the individual, or from the individual's prior or other current employer(s) for work involving radiation exposure, that discloses the nature and the amount of any occupational dose that the individual received during the current year; or Cont'd... |
