Dr Robert Ricks retired in September as director of the Radiation Emergency Assistance Center/ Training Site (REAC/TS) at the Oak Ridge Institute for Science and Education, in Oak Ridge, Tennessee, USA. He also directs the World Health Organization Collaborating Center for Radiation Emergency Medical Preparedness and Assistance Network (REMPAN) for the USA. REMPAN provides emergency medical assistance to people overexposed to radiation and facilitates long-term care and follow-up to accident victims.
REAC/TS is the USA’s emergency medical response centre for radiation accidents and also serves as a centre for state-of-the-art continuing medical management of radiation accidents. The US Department of Energy (DoE) provides funding for the centre.
Worldwide, 427 major radiation accidents occurred between 1944 and June 2004, according to information supplied by REAC/TS. Of these, 19 were unplanned criticalities; 316 involved radiation devices, including sealed sources, X-ray devices, accelerators and radar generators; and 92 involved radioisotopes.
These accidents resulted in a total of 134 deaths: 30 in the USA (including four non-radiation related accident fatalities), 32 in the former Soviet Union (including three non-radiation related fatalities) and 72 in other areas of the world (including two non-radiation related fatalities). The accidents also resulted in significant, non-lethal exposures to an additional 3051 people.
RADIATION INJURIES
In terms of human exposure, it is important to realise that, from a medical standpoint, radiation does not cause any unique diseases, Ricks told NEI. The symptoms of radiation exposure are all present in other disorders that doctors are familiar with and treat on a daily basis.
About 40-50 years ago, the medical profession responded to the early cases of severe radiation exposure with state-of-the-art medical management, including bone marrow suppression, antibiotic therapy, platelet infusion to prevent bleeding and good medical management. The evolution in medical management for severe radiation exposure has primarily been in medical techniques related to bone marrow transplant.
The first bone marrow transplants for treatment of severe radiation exposure were done in Oak Ridge even before the creation of REAC/TS, Ricks pointed out.
New therapies were developed in the mid-1980s using techniques associated with genetic engineering. Scientists began to identify the genetic sequence of the molecules that regulate the production of cytokines, which regulate production of blood cells and programme cell replication. These molecules can be produced in high concentrations and administered by injection to an injured individual to stimulate rapid cell and bone marrow growth.
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The symptoms of radiation exposure are all present in other disorders that doctors are familiar with and treat on a daily basis |
Doctors have used cytokines since 1986 to try to rescue individuals exposed to high radiation doses. However, not everyone responds to the therapy, said Ricks, explaining that an individual’s response depends on how many of the patients cells are able to recognise and respond to the signals from the injected cytokines.
Newer medical techniques include stimulation of expanded production of peripheral stem cells in the bone marrow and transfusions of umbilical cord blood.
Total body radiation in an accident is rare, Ricks pointed out. Treatment of bone marrow is the most advanced and has benefited from extensive cancer research. Doctors have been less successful in treating high doses of radiation to the gut, vascular system and skin.
Researchers are developing techniques of grafting artificial skin over the lesions from severe radiation burns to the skin, Ricks said. One promising technique uses cytokines to grow pork skin cells on a mesh network. The skin is then sewn into place over the lesion. Ricks explained that the success of this technique depends on a number of factors, including timing of the treatment and the total area of the patient’s skin that was burned. Individual factors also affect the success of the treatment, including the patient’s smoking history and susceptibility to infection.
All of the techniques used in treating radiation injuries were developed from treatments for patients with non-radiation related diseases and injuries that produce similar symptoms, such as cancers and severe burns. Ricks stressed that these are techniques that are used daily in major medical centres in all industrialised nations.
RESPONSE EQUIPMENT
The World Health Organization’s REMPAN has put in place a framework to take these techniques anywhere in the world they are needed to respond to a radiation incident. REMPAN also is prepared to remove victims to major research hospitals as the immediate emergency is brought under control – particularly if the incident occurred in a remote area, or one without an adequate medical infrastructure.
Having participated in a number of these responses, Ricks said that the equipment needed is now “very portable, and can easily be taken into remote areas.” The DoE has the capability to respond to radiation accidents or incidents in the USA. The REAC/TS team, which is the US component of the international response effort, can reach anywhere in the world within 24 hours. “We’re wheels-up for any event in the USA within four hours, and within six hours for any event outside the USA.”
A number of other countries have response capabilities similar to those in the USA, Ricks said, noting that the International Atomic Energy Agency (IAEA) coordinates responses to an incident at the request of the country involved. The IAEA’s role goes beyond the medical concerns, and includes recovery and stabilisation of the radioactive material involved.
Countries that are not IAEA members can request assistance from the agency’s emergency operations centre in Vienna in the event of a radiation accident.
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The greatest medical risk from a radiation accident occurs from 48 hours to two or three weeks after the event |
If the IAEA determines the expertise of the US REAC/TS team is needed, the international agency will notify the US energy secretary, as well as other US agencies such as Health and Human Services and the Office of the President.
Some requests for assistance also have come directly to REAC/TS, Ricks said. In these cases, REAC/TS contacts the DoE’s emergency operations office in Washington, DC, to obtain the necessary US government commitments.
MEDICAL RESPONSE WINDOW
Ricks pointed out that the nature of radiation injuries offer a window of time for the medical response team to reach their patients. The greatest medical risk from a radiation accident occurs from 48 hours to two or three weeks after the event, which allows time for equipment and personnel to be mobilised. Even in a criticality accident, the first deaths occur about 35 hours after the incident, Ricks said.
Incidents in remote locations generally involve the accidental or deliberate misuse of sealed radioactive sources. Medical response to these accidents does not have to be as rapid as the response to a major criticality accident, Ricks said, adding that these accidents are often not discovered until days or weeks after they happen. In Georgia, for example, there were three separate incidents in which workers picked up strontium sources without knowing what they were handling. In all three cases, the victims initially were treated in the Republic of Georgia and later moved to larger hospitals in Moscow, France and Germany.
When asked about any special considerations if a child is involved in the incident, such as a case in the 1980s when a five-year old Brazilian girl played with caesium after her father, an illiterate junk dealer, broke open a high-activity medical source, Ricks said that doctors would not do anything different than for an adult. However, children and the elderly are more sensitive to radiation than healthy adults – a comparable dose will affect a child much more severely than an adult.
REAC/TS provides medical response, advice and consultation worldwide around the clock through the DoE’s Office of Emergency Response. Services include rapid assessment of radiation doses from internal radioactive materials; deployable medical capabilities for on-site assistance and treatment for all types of radiation exposure; and continuing medical and health physics courses. In the event of a nuclear or radiological attack in the USA, REAC/TS would transition to the Department of Homeland Security.
The REAC/TS team has extensively documented every radiation accident and details of the medical management of the victims. The international response team looks at why and how the accident occurred and what lessons can be learned to help prevent similar accidents in the future. The IAEA has used this information to develop a body of preventative measures.
Ricks has led a team of physicians, nurses and health physicists in providing advice and consultation for worldwide radiation assistance and collaboration with other WHO centres. He was a member of the International Chernobyl Project and has responded to major radiation accidents in Brazil, El Salvador, Japan and Peru. He also serves as a consultant to the IAEA in Vienna.
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