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United States Department of Agriculture

Agricultural Research Service

Research Project: POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT Title: Biocontrol agents fly through x-ray scans

Author
item Follett, Peter

Submitted to: Biocontrol News and Information
Publication Type: Other
Publication Acceptance Date: April 8, 2010
Publication Date: June 10, 2010
Citation: Follett, P.A. 2010. Biocontrol agents fly through x-ray scans. Biocontrol News and Information. 31(2): 11N-12N.

Interpretive Summary: Since 9/11, intensive baggage scans using various cabinet x-ray systems have become routine. The increased use of x-ray scanning has prompted many biological control practitioners to ask about possible harmful effects of x-ray radiation on shipments of live biological material, such as biological control agents. The acute threshold limit value (TLV, highest dose producing no measurable effect) for the most sensitive insect is estimated at 1 Gy. The radiation dose typically received by objects scanned by a cabinet x-ray system is 0.01 mGy (0.00001 Gy) or about 1/100,000th of the TLV estimated for the most sensitive insect. Baggage x-ray scans expose biological materials to doses far below those that might have any harmful effects.

Technical Abstract: Since 9/11, intensive baggage scans using various cabinet x-ray systems have become routine. The increased use of x-ray scanning has prompted many biological control practitioners to ask about possible harmful effects of x-ray radiation on shipments of live biological material, such as biological control agents. A primer in radiation biology is presented. The Threshold Limit Value (TLV) is the level of radiation to which it is believed a worker can be exposed day after day for a working lifetime without adverse effects. This is an important number to calculate for the occupational health of people who work near a source of radiation, such as medical x-ray technicians. An acute TLV for insects would be helpful for evaluating the risk of exposure to x-ray scans. Insects are fully sterilized at doses between about 50 and 400 Gy. Insect irradiation studies normally involve application of radiation doses within the range that produce a desired response (e.g. sterility), and seldom report information on threshold doses, i.e., doses that cause no measurable effects on insect reproduction or fitness. An acute TLV is likely highly variable depending on the species of insect and other factors. The acute threshold limit value (TLV) for the most sensitive insect is estimated at 1 Gy. The radiation dose typically received by objects scanned by a cabinet x-ray system is 0.01 mSv (0.00001 Gy) or less. This dose is about 1/100,000th of the TLV estimated for the most sensitive insect (1 Gy). The level of radiation exposure from a check-in baggage x-ray scanner (CAT scan) is about 10 times higher or 0.0001 Gy, but still harmless. Baggage x-ray scans expose biological materials to doses far below those that might have any harmful effects.

Last Modified: 12/19/2014
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