Doran M. Christensen

Ionizing radiation injuries and illnesses

Although the spectrum of information related to diagnosis and management of radiation injuries and illnesses is vast and as radiation contamination incidents are rare, most emergency practitioners have had little to no practical experience with such cases. Exposures to ionizing radiation and internal contamination with radioactive materials can cause significant tissue damage and conditions. Emergency practitioners unaware of ionizing radiation as the cause of a condition may miss the diagnosis of radiation-induced injury or illness. This article reviews the pertinent terms, physics, radiobiology, and medical management of radiation injuries and illnesses that may confront the emergency practitioner.

Role of dicentric analysis in an overarching biodosimetry strategy for use following a nuclear detonation in an urban environment.

AbstractIn the moments immediately following a nuclear detonation, casualties with a variety of injuries including trauma, burns, radiation exposure, and combined injuries would require immediate assistance. Accurate and timely radiation dose assessments, based on patient history and laboratory testing, are absolutely critical to support adequately the triage and treatment of those affected. This capability is also essential for ensuring the proper allocation of scarce resources and will support longitudinal evaluation of radiation-exposed individuals and populations. To maximize saving lives, casualties must be systematically triaged to determine what medical interventions are needed, the nature of those interventions, and who requires intervention immediately. In the National Strategy for Improving the Response and Recovery for an Improvised Nuclear Device (IND) Attack, the U.S. Department of Homeland Security recognized laboratory capacity for radiation biodosimetry as having a significant gap for performing mass radiation dose assessment. The anticipated demand for radiation biodosimetry exceeds its supply, and this gap is partly linked to the limited number and analytical complexity of laboratory methods for determining radiation doses within patients. The dicentric assay is a key component of a cytogenetic biodosimetry response asset, as it has the necessary sensitivity and specificity for assessing medically significant radiation doses. To address these shortfalls, the authors have developed a multimodal strategy to expand dicentric assay capacity. This strategy includes the development of an internet-based cytogenetics network that would address immediately the labor intensive burden of the dicentric chromosome assay by increasing the number of skilled personnel to conduct the analysis. An additional option that will require more time includes improving surge capabilities by combining resources available within the country’s 150 clinical cytogenetics laboratories. Key to this intermediate term effort is the fact that geneticists and technicians may be experts in matters related to identifying chromosomal abnormalities related to genetic disorders, but they are not familiar with dosimetry for which training and retraining will be required. Finally, long-term options are presented to improve capacity focus on ways to automate parts of the dicentric chromosome assay method.

Management of Ionizing Radiation Injuries and Illnesses, Part 3: Radiobiology and Health Effects of Ionizing Radiation

Ionizing radiation exposure can induce profound changes in intracellular components, potentially leading to diverse health effects in exposed individuals. Any cellular component can be damaged by radiation, but some components affect cellular viability more profoundly than others. The ionization caused by radiation lasts longer than the initial inciting incident, continuing as 1 ionization incident causes another. In some cases, damage to DNA can lead to cellular death at mitosis. In other cases, activation of the genetic machinery can lead to a genetic cascade potentially leading to mutations or cell death by apoptosis. In the third of 5 articles on the management of injuries and illnesses caused by ionizing radiation, the authors provide a clinically relevant overview of the pathophysiologic process associated with potential exposure to ionizing radiation.

Management of Ionizing Radiation Injuries and Illnesses, Part 4: Acute Radiation Syndrome

To provide proper medical care for patients after a radiation incident, it is necessary to make the correct diagnosis in a timely manner and to ascertain the relative magnitude of the incident. The present article addresses the clinical diagnosis and management of high-dose radiation injuries and illnesses in the first 24 to 72 hours after a radiologic or nuclear incident. To evaluate the magnitude of a high-dose incident, it is important for the health physicist, physician, and radiobiologist to work together and to assess many variables, including medical history and physical examination results; the timing of prodromal signs and symptoms (eg, nausea, vomiting, diarrhea, transient incapacitation, hypotension, and other signs and symptoms suggestive of high-level exposure); and the incident history, including system geometry, source-patient distance, and the suspected radiation dose distribution.

Management of Ionizing Radiation Injuries and Illnesses, Part 1: Physics, Radiation Protection, and Radiation Instrumentation

Ionizing radiation injuries and illnesses are exceedingly rare; therefore, most physicians have never managed such conditions. When confronted with a possible radiation injury or illness, most physicians must seek specialty consultation. Protection of responders, health care workers, and patients is an absolute priority for the delivery of medical care. Management of ionizing radiation injuries and illnesses, as well as radiation protection, requires a basic understanding of physics. Also, to provide a greater measure of safety when working with radioactive materials, instrumentation for detection and identification of radiation is needed. Because any health care professional could face a radiation emergency, it is imperative that all institutions have emergency response plans in place before an incident occurs. The present article is an introduction to basic physics, ionizing radiation, radiation protection, and radiation instrumentation, and it provides a basis for management of the consequences of a radiologic or nuclear incident.

Dose coefficients for intakes of radionuclides via contaminated wounds.

The NCRP Wound Model, which describes the retention of selected radionuclides at the site of a contaminated wound and their uptake into the transfer compartment, has been combined with the ICRP element-specific systemic models for those radionuclides to derive dose coefficients for intakes via contaminated wounds. These coefficients can be used to generate derived regulatory guidance (i.e., the activity in a wound that would result in an effective dose of 20 or 50 mSv, or in some cases, a organ-equivalent dose of 500 mSv) and clinical decision guidance (i.e., activity levels that would indicate the need for consideration of medical intervention to remove activity from the wound site, administration of decorporation therapy or both). Data are provided for 38 radionuclides commonly encountered in various activities such as nuclear weapons, fuel fabrication or recycling, waste disposal, medicine, research, and nuclear power. These include 3H, 14C, 32P, 35S, 59Fe, 57,58,60Co, 85,89,90Sr, 99mTc, 106Ru, 125,129,131I, 134,137Cs, 192Ir, 201Tl, 210Po, 226,228Ra, 228,230,232Th, 234,235,238U, 237Np, 238,239,240,241Pu, 241Am, 242,244Cm, and 252Cf.

Case Report: Industrial X-Ray Injury Treated With Non-Cultured Autologous Adipose-Derived Stromal Vascular Fraction (SVF).

Abstract Local cutaneous injuries induced by ionizing radiation (IR) are difficult to treat. Many have reported local injection of adipose-derived stromal vascular fraction (SVF), often with additional therapies, as an effective treatment of IR-induced injury even after other local therapies have failed. The authors report a case of a locally recurrent, IR-induced wound that was treated with autologous, non-cultured SVF without other concurrent therapy. A nondestructive testing technician was exposed to 130 kVp x rays to his non-dominant right thumb on 5 October 2011. The wound healed 4 mo after initial conservative therapy with oral/topical &agr;-tocopherol, oral pentoxifylline, naproxen sodium, low-dose oral steroids, topical steroids, hyperbaric oxygen therapy (HBOT), oral antihistamines, and topical aloe vera. Remission lasted approximately 17 mo with one minor relapse in July 2012 after minimal trauma and subsequent healing. Aggressive wound breakdown during June 2013 required additional therapy with HBOT. An erythematous, annular papule developed over the following 12 mo (during which time the patient was not undergoing prescribed treatment). Electron paramagnetic resonance (EPR) done more than 2 mo after exposure to IR revealed dose estimates of 14 ± 3 Gy and 19 ± 6 Gy from two centers using different EPR techniques. The patient underwent debridement of the 0.5 cm papular area, followed by SVF injection into and around the wound bed and throughout the thumb without complication. Eleven months post SVF injection, the patient has been essentially asymptomatic with an intact integument. These results raise the possibility of prolonged benefit from SVF therapy without the use of cytokines. Since there is currently no consensus on the use of isolated SVF therapy in chronic, local IR-induced injury, assessment of this approach in an appropriately powered, controlled trial in experimental animals with local radiation injury appears to be indicated.

Management of Ionizing Radiation Injuries and Illnesses, Part 5: Local Radiation Injury

This final article in the series on the medical management of ionizing radiation injuries and illnesses focuses on the effects of acute ionizing radiation exposure to one of the largest organ systems of the body-the skin. These injuries may extend beyond the skin into deeper tissues and cause local radiation injury. There are numerous causes of these injuries, ranging from industrial incidents to medical procedures. In the present article, the authors characterize the clinical course, pathophysiologic process, sources of injury, diagnosis, and management of local radiation injury and describe a clinical scenario. This information is important for primary care physicians, to whom patients are likely to initially present with such injuries.

Management of Ionizing Radiation Injuries and Illnesses, Part 2: Nontherapeutic Radiologic/Nuclear Incidents

In the second of 5 articles on the management of injuries and illnesses caused by ionizing radiation, the authors discuss nontherapeutic radiologic/nuclear incidents: use of a radiologic exposure device, use of a radiologic dispersal device, nuclear power plant safety failure, and detonation of an improvised nuclear device. The present article focuses on how such incidents--whether involving deliberate or accidental methods of radiation exposure--produce casualties and how physicians need to understand the pathologic process of injuries caused by these incidents. To identify the diagnoses associated with nontherapeutic exposure in time to improve morbidity and mortality, physicians must maintain a high index of suspicion when faced with a specific constellation of symptoms. In some scenarios, the sheer number of uninjured, unaffected persons who might present to health care institutions or professionals may be overwhelming. Public health and safety issues may seriously disrupt the ability to respond to and recover from a radiologic and nuclear incident, especially a nuclear detonation.

A holistic approach to disaster medical education.

1. Einstein Elkins Park Department of Emergency Medicine, Einstein Healthcare Network, Philadelphia, Pennsylvania USA 2. Emergency Preparedness, Einstein Healthcare Network, Philadelphia, Pennsylvania USA 3. Radiation Emergency Assistance Center/ Training Site, Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee USA 4. National Security and Emergency Management Programs, Oak Ridge Institute for Science and Education, Arlington, Virginia USA