How to Perform a Survey for Radiation Contamination

• Survey with Geiger-Mueller Detector
• Probe held about 1/2 inch from surface
• Move at a rate of 1 to 2 inches per second
• Follow a systematic pattern (see below)
• Document readings in counts per minute (CPM) on a body chart (PDF - 49 KB)
• Compare radiation survey results before and after decontamination procedure
• Use nuclear medicine and radiation therapy technologists or others familiar with the use of radiation detection instruments
• Goal is < 2 times background radiation reading
• In general, areas that register more than twice the previously determined background radiation level are considered contaminated.
• For accidents involving alpha particle emitters, if the reading is less than twice the background radiation level, the person is not contaminated to a medically significant degree. If the accident circumstances indicate that an alpha particle emitter (such as plutonium) or low-energy beta emitter could be a contaminant, a health physicist should always be consulted.
• Specifics of the survey
• Have the person stand on a clean pad.
• Instruct the person to stand straight, feet spread slightly, arms extended with palms up and fingers straight out.
• Monitor both hands and arms; then repeat with hands and arms turned over.
• Starting at the top of the head, cover the entire body, monitoring carefully the forehead, nose, mouth, neckline, torso, knees, and ankles.
• Have the person turn around; repeat the survey on the back of the body.
• Monitor the soles of the feet.

Adapted from How to Detect Radiation (Radiation Emergency Assistance Center/Training Site (REAC/TS))