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RADIATION EXPOSURE

Acute Radiation Syndrome

Whole-body or significant partial-body exposure to high levels of radiation can cause Acute Radiation Syndrome (ARS ), also known as radiation sickness. The deadly effects of ionizing radiation are wide-ranging and encompass both whole body and organ-specific damage. ARS typically includes a range of physical signs and symptoms that reflect severe damage to specific parts of the body, including the bone marrow, blood, the gastrointestinal tract, and the central nervous system. The particular organs affected depend, in part, upon the radiation exposure level and the susceptibility of the individual organs. At lower radiation levels, bone marrow effects occur that can lead to increased susceptibility to infection, anemia, and uncontrolled bleeding. At slightly higher radiation levels, the gastrointestinal tract can be damaged, causing nausea, vomiting, and diarrhea, as well as the release of intestinal bacteria into the bloodstream that can further stress the depleted immune system. At the highest radiation levels, the brain, spinal cord, and lungs can be affected. These highest exposure levels are almost universally fatal, even with aggressive therapy. Even low doses of radiation can result in increased death if accompanied by physical injuries, infections, and/or blood loss. Long-term effects include loss of normal function or fibrosis in a wide range of organs and body tissues and, ultimately, a higher risk of cancer. In most cases, the deadly effects of higher doses of radiation exposure can be lessened by early appropriate triage and medical treatment decisions.

Recovery of the blood system depends on prompt treatment, to preserve or enhance the ability of the remaining stem cells in the bone marrow and to divide and become mature blood cells to bring the immune and blood system back to working well enough to prevent otherwise fatal infections and internal bleeding. Other radiation injuries take more time to show up. This extra time provides an opportunity to give medications before full expression of radiation sickness, potentially saving lives.

Cutaneous Radiation Injury

Significant radiation exposure of the skin and underlying tissue may also cause Cutaneous Radiation Injury (CRI), also known as a radiation burn. The severity of the radiation burn depends largely on the magnitude of the radiation exposure. Exposure to large doses of radiation can damage the skin's cell layers, causing inflammation, reddening, and skin peeling. More severe exposures will result in hair loss, blistering, and skin ulceration.

HHS has requirements for the capability to treat thousands of burn victims following a nuclear detonation. Also, burn wounds resulting from IND detonation are likely to be accompanied by blunt trauma, lacerations, and radiation-related injuries. Burn injuries which are full-thickness in nature would require autografts for treatment. Large burn injuries will also have immediate life-threatening complications. Although severe burns ultimately require skin grafting, these surgical procedures for definitive care can be delayed (for several days) if the appropriate field-care treatments are used. The need is particularly high to develop products for definitive care that can reduce the labor-intensity and resource-intensity of care for severe and widespread burns.

Radioactive particles can also be taken into the body through inhalation, ingestion, or wound contamination, and can be absorbed into organs such as bone, liver, or lymph nodes. Once absorbed, the radioactive particles continue to emit ionizing radiation to the surrounding tissues, potentially leading to cell death, organ dysfunction, fibrosis, or malignancy. Rapid removal of these particles from the body is critical. Finally, in situations that result in people becoming internally contaminated with radioactive particles from fallout contamination or a radiological dispersal devices , special tests of blood, urine, sputum, hair, and skin/wound sites will help identify the radiation contamination of organ doses received. These tests will also show the success of therapy for removal of these particles from the body.

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