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Radiation Exposure and Contamination
Prevention of Radiation Exposure and Contamination
Protection from radiation exposure is accomplished by avoiding contamination with radioactive material; by minimizing the duration of exposure; maximizing the distance from the source of radiation, and shielding the source. During some imaging procedures that involve ionizing radiation and during radiation therapy, parts of the body that are near, but not the target of the imaging procedure or therapy, should be shielded to the extent possible with lead. Although shielding of personnel with lead aprons or commercially available transparent shields effectively reduces exposure to low-energy scattered x-rays from diagnostic and interventional imaging studies, these aprons and shields are almost useless in reducing exposure to the high-energy gamma rays produced by radionuclides that would likely be used in a terrorist incident or be released in a nuclear power plant accident. In such cases, measures that can minimize exposure include using standard precautions, undergoing decontamination efforts, and maintaining distance from contaminated patients when not actively providing care. All personnel working around radiation sources should wear dosimeter badges if they are at risk for exposures>10% of the maximum permissible occupational dose (0.05 Sv). Self-reading electronic dosimeters are helpful for monitoring the cumulative dose received during an incident. After widespread high-level environmental contamination from a nuclear power plant accident or intentional release of radioactive material, exposure can be reduced either by Sheltering in place Evacuating the contaminated area The better approach depends on many event-specific variables, including The time elapsed since initial release Whether release has stopped or is ongoing Weather conditions Availability and type of shelter Evacuation conditions (eg, traffic, transportation availability) The public should follow the advice of local public health officials as given on emergency alert notification systems. If in doubt, shelter in place is the best option until additional information becomes available. If sheltering is recommended, the center of a concrete or metal structure above or below grade (eg, in a basement) is best. If the event is the detonation of a nuclear weapon, shelter in place as quickly as an effective shelter can be found for the first few hours after the detonation and then follow the advice of local emergency response officials. Consistent and concise messages from public health officials can help reduce unnecessary panic and reduce the number of emergency department visits from people at low risk, thus keeping the emergency department from being overwhelmed. Such a communication plan should be developed prior to any event. A plan to decrease the demand on emergency department resources by providing an alternative location for first aid, decontamination, and counseling of people without emergent medical problems is recommended. People living within 16 km (10 miles) of a nuclear power plant should have ready access topotassium iodidetablets. These tablets can be obtained from local pharmacies and some public health agencies. Radioprotective medications, such as thiol compounds with radical scavenging properties, have been shown to reduce mortality when given before or at the time of irradiation in patients undergoing chemotherapy and/or radiation therapy. Additional investigations are needed to demonstrate benefit in nonmedical radiation exposures (eg, nuclear power plant accidents). Amifostineis a powerful injectable radioprotective agent in this category. It is used clinically to prevent xerostomia in patients undergoing radiation therapy. Adverse effects include nausea and vomiting, hypotension, and decreased serum calcium. Exposure of an unborn child to this medication could cause birth defects. Palifermin, a mucocutaneous epithelial growth factor, is a modified version of a naturally occurring human protein called keratinocyte growth factor (KGF) that is manufactured in a laboratory. It is used to reduce the chances of developing severe mucositis and decrease duration of mucositis in patients who receive high doses of chemotherapy and radiation followed by stem cell rescue.Palifermincan interact withheparin, thus intravenous lines should be rinsed with saline prior to and afterpaliferminadministration. Adverse effects include rash, pancreatitis, fever, and peripheral edema. Exposure of an unborn child to this drug could cause birth defects. Dosage is 60 mcg/kg once per day. 