Radiation Exposure Limits

The maximum permissible doses established by KDHE for radiation workers are summarized in the table below.  However, it is important that every radiation worker understands that in spite of these limits, the regulations also require that every radiation worker keeps his or her exposures As Low As Reasonably Achievable (ALARA).  

Exposed Part of Body

Abbreviation

Limit (mrem)

Time Period

Whole Body (Deep Dose Equivalent)

DDE

5,000

Annually

Lens of the Eye (Lens Dose Equivalent)

LDE

15,000

Annually

Skin (Shallow Dose Equivalent - Whole Body)

SDE-WB

50,000

Annually

Extremity (Shallow Dose Equivalent - Maximum Extremity)

SDE-ME

50,000

Annually

Total Organ Dose Equivalent

TODE

50,000

Annually

Fetus of a Declared Pregnant Woman

DPW

500

Gestation period

NOTE: ·        

  • Minors (individuals under 18 years old) are limited to 10% of these values.
  • Extremities include hands, elbows, and arms below the elbows, and feet, knees and legs below the knee.
  • A declared pregnant woman is limited to 500 mrem for the entire gestation period unless she has already received 500 mrem since conception.  In this case, she is allowed 50 mrem for the remainder of the pregnancy.
  • The Total Effective Dose Equivalent (TEDE) is the sum of all internal and external exposures.
  • Weighting factors (WT) are used in calculating the effective dose equivalent, and are most commonly used for internal exposures (i.e., when radioactive materials are injested, inhaled, etc.).  A weighting factor for an organ or tissue is the proportion of risk of stochastic effects resulting from irradiation of that organ or tissue to the total risk of stochastic effects when the whole body is irradiated uniformly.  The values for the weighting factors are summarized below:  
ORGAN DOSE WEIGHTING FACTORS
Organ or Tissue WT
Gonads 0.25
Breast 0.15
Red bone marrow 0.12
Lung 0.12
Thyroid 0.03
Bone surfaces 0.03  
Remainder 0.30*
Whole Body 1.00
* 0.30 results from 0.06 for each of 5 "remainder" organs (excluding the skin and the lens of the eye) that receive the highest doses.

    

Last modified: Jul 08, 2014
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