Radiation Protection

Radiation -- Occupational Exposure Annual Limits

KDHE Regulations [KDHE K.A.R. 28-35-212 (a)] require that we keep your radiation exposure below the following limits:

Annual Radiation Limits

Whole Body Deep Exposure (internal + external)

5,000 mrem

Extremities (basically, hands and feet)

50,000 mrem

Skin of the whole body (shallow dose)

50,000 mrem

Lens of the Eye

15,000 mrem


Declared Pregnant worker (for duration of the pregnancy)

500 mrem


We are given these limits, but we are also held to a stricter standard, described as the ALARA concept.  We all (including the radiation worker) are required to keep radiation exposures:

As Low As Reasonably Achievable

Practicing ALARA means that all reasonable actions will be taken to make sure the exposures that radiation workers receive are as low as possible.  This is done by utilizing time, distance and shielding; and by avoiding any possibility of an internal exposure:


Minimize the time spent near radioactive materials:

  • -Put stock solutions back in storage as soon as possible.
  • Change or survey gloves frequently.  When your gloves are contaminated, they may be irradiating your hands continuously while they are worn.
  • Understand procedures so that processes can be performed efficiently.
  • Minimize the amount of time that your hands are over open containers of radioactive materials.


Maximize the distance between you and the radioactive materials:

  • Use forceps, tongs or tweezers to move small containers of radioactive materials, filters or other items containing rad. materials.
  • Place unshielded radioactive waste away from populated areas.


Use shielding as much as possible:

  • Use plastic, Plexiglas or acrylic shielding for beta emitters (P-32, S-35, C-14, etc.) or lead shielding for gamma emitters (I-125, Zn-65, etc.).  A one centimeter thickness of plastic will shield 100% of the beta particles emitted by the radioisotopes used at KUMC.
  • Using shielding for waste containers, sample holders, storage areas and even work spaces.
  • Wear safety glasses to protect your eyes from beta particle radiation.

Avoiding Internal Exposures:

For internal exposures (i.e., radioactive materials taken inside the body), exposures are minimized by limiting the possibilities of taking radioactive materials into the body via ingestion, inhalation, absorption, or injection.  Internal exposures can be avoided by:

  • Not eating, drinking, smoking, applying cosmetics, etc., in posted radioactive materials areas.
  • Wearing appropriate personal protective equipment like gloves and lab coats, and either changing them or surveying them often for contamination.
  • Labeling all items that contain or might be contaminated by radioactive materials.
  • Using proper ventilation like a fume hood when working with radioactive materials that might become airborne.  This is particularly important when using radioactive iodine like I-125 or I-131.  These radioisotopes often become airborne gasses at room temperatures.
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