Operational Testing of a Combined Hardware-Software Strategy for Triage of Radiologically-Contaminated Persons.

After a radiological dispersal device (RDD) event, it is possible for radionuclides to enter the human body through inhalation, ingestion, and skin and wound absorption. The dominant pathway will be through inhalation. From a health physics perspective, it is important to know the magnitude of the intake to perform dosimetric assessments. From a medical perspective, removal of radionuclides leading to dose (hence risk) aversion is of high importance. The efficacy of medical decorporation strategies is extremely dependent upon the time of treatment delivery after intake. The "golden hour," or more realistically 3-4 h, is imperative when attempting to increase removal of radionuclides from extracellular fluids prior to cellular incorporation. To assist medical first response personnel in making timely decisions regarding appropriate treatment delivery modes, a software tool has been developed which compiles existing radionuclide decorporation therapy data and allows a user to perform simple triage leading to potential appropriate decorporation treatment strategies. Three triage algorithms were included: (1) multi-parameter model (MPM), (2) clinical decision guidance (CDG) model, and (3) annual limit on intake (ALI) model. A radiation triage mask (RTM) has simultaneously been developed to provide a simple and rapid hardware solution for first responders to triage internally exposed personnel in the field. The hardware/software strategy was field tested with a military medical unit and was found by end-users to be relatively simple to learn and use.

The role of the health physicist in nuclear security.

Health physics is a recognized safety function in the holistic context of the protection of workers, members of the public, and the environment against the hazardous effects of ionizing radiation, often generically designated as radiation protection. The role of the health physicist as protector dates back to the Manhattan Project. Nuclear security is the prevention and detection of, and response to, criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities, or associated activities. Its importance has become more visible and pronounced in the post 9/11 environment, and it has a shared purpose with health physics in the context of protection of workers, members of the public, and the environment. However, the duties and responsibilities of the health physicist in the nuclear security domain are neither clearly defined nor recognized, while a fundamental understanding of nuclear phenomena in general, nuclear or other radioactive material specifically, and the potential hazards related to them is required for threat assessment, protection, and risk management. Furthermore, given the unique skills and attributes of professional health physicists, it is argued that the role of the health physicist should encompass all aspects of nuclear security, ranging from input in the development to implementation and execution of an efficient and effective nuclear security regime. As such, health physicists should transcend their current typical role as consultants in nuclear security issues and become fully integrated and recognized experts in the nuclear security domain and decision making process. Issues regarding the security clearances of health physics personnel and the possibility of insider threats must be addressed in the same manner as for other trusted individuals; however, the net gain from recognizing and integrating health physics expertise in all levels of a nuclear security regime far outweighs any negative aspects. In fact, it can be argued that health physics is essential in achieving an integrated approach toward nuclear safety, security, and safeguards.

Canadian Cardiovascular Society position statement on radiation exposure from cardiac imaging and interventional procedures.

Exposure to ionizing radiation is a consequence of many diagnostic and interventional cardiac procedures. Radiation exposure can result in detrimental health effects because of deterministic (eg, skin reaction) and stochastic effects (eg, cancer). However, with the levels experienced during cardiac procedures these risks can be difficult to quantify. Healthcare providers and patients might not fully appreciate radiation-related risks. Though in many cases radiation exposure cannot be avoided, a practice of minimizing exposures to levels "as low as reasonably achievable" (ALARA principle) without compromising the utility of the procedure is encouraged. The purpose of this document is to inform health care providers on the key concepts related to radiation risk from common cardiac procedures and provide specific recommendations on ensuring quality of care.

Combined hardware--software considerations for triage of internally contaminated personnel.

Medical response to a radiological emergency involves first assessing, triaging and treating trauma, followed by determining potential hazard from radiological intake. A combined hardware-software strategy is required for this mission. The hardware strategy should consist of a dedicated detector suite capable of alpha, beta and gamma radiation detection, identification and quantification suitable for order of magnitude dose assessment. The hardware platform should provide a simple user interface suitable for field deployment. The software should provide first-on-the-scene responders with the ability to perform radiological triage in a mass casualty type event, physicians with the ability to assign treatment regimes, and long-term care medical personnel with information to provide continual risk reassessment of the patient taking into account toxicology of the decorporation therapy and dose aversion. The software should be rich in data, yet accessible through a simple user interface. Practicing in a radiological emergency exercise environment with the equipment is crucial to its efficacy in a real emergency.

First response considerations for children exposed to a radiological dispersal device.

Children are considered a vulnerable population during an accidental or deliberate release of radioactive material to the environment due to the fact that they have more active cell division compared with the adult population and therefore detrimental effects promulgate very quickly. Additionally, physical and social characteristics of children make them more prone to internalise a toxin (for example, children are closer to the ground where heavy aerosols can collect; children also have more relaxed sanitary habits compared with the adult population, which aids in hand-to-mouth transfer of contaminants). To confound matters, many emergency protocols are based upon a reference as opposed to a child. Although numerous radiological response exercises have been conducted in the years post 9/11, very few have utilised children actively in the scenarios. This paper considers observations made during a NATO exercise with scenarios covering radiological releases and which utilised a variety of children as exercise participants.

Radiological hazard estimates from contaminated C7 canisters on the C4 protective mask.

This study compares the external hazard posed by radioactive material trapped in the C7 filter canister of the Canadian C4 full-face mask to the internal hazard from the portion of the material that bypasses the mask and is inhaled. Published measured protection factors (PFs) are used to define the ratio of radioisotope concentration outside of the mask to that inside the mask. The hazards for a variety of radioisotopes are quantified using a Monte Carlo model for the external hazard from the contaminated canister and International Commission on Radiological Protection Publication 68 internal dose coefficients for 1 micron internalized particulate material. In general, the external hazard from a contaminated canister exceeds the internal hazard from material that bypasses the filters for only the most highly protective negative-pressure masks and then only for gamma emitting materials. Our model shows that it is highly unlikely that a canister can become contaminated with enough radioactive material to pose an immediate threat to the wearer, even for pessimistic radiological dispersal device scenarios, when the mask is being worn properly. The "as low as reasonably achievable" (ALARA) principle, however, suggests that filters should be changed as frequently as practical, and the dose measured in the filter may be useful for determining dose of record and for forensic investigations.

Radiation protection issues related to Canadian museum operations.

Museums in Canada have been found to possess radioactive items. The origin of the radiation can be broadly categorized as either natural (generally, radioactive ores) or anthropogenic (generally, luminous gauges). Radioluminescent gauges, especially bearing radium (226Ra), can also generate significant radiation fields. This is especially true if many gauges are located in close proximity. In addition, the radon may out-gas from these gauges, and generate a loose contamination problem in enclosed spaces (such as display cases). Radioactive ores, bearing naturally occurring uranium and thorium, can generate radiation fields many times greater than the ambient background levels. In addition, they will increase the ambient radon level and potentially generate loose contamination. In this paper, we discuss the specific results of radiological decommissioning at three museums: the National Air Force Museum of Canada (Trenton, Ontario); the Quebec Air and Space Museum (Montreal, PQ); and the Canadian Museum of Nature (Aylmer, PQ). In addition, a radiological survey performed at Canadian Forces Detachment Mountain View (Mountain View, Ontario) of surplus aircraft is included. The primary conclusion is that museums holding radioactive materials may have detectable levels of loose Ra and progeny contamination. They, therefore, have a requirement to be surveyed for loose contamination periodically with the potential for periodic decontamination caused by radon out-gassing. In addition, public access to displays bearing radioactive material should generally be restricted, and comprehensive radiation safety and security programs at museum facilities should be developed and enacted.

Release limits and decontamination efficacy for tritium: lessons learned outside nuclear power operations.

Various pieces of equipment in use by the Canadian Department of National Defence (DND) contain radiation-emitting components. One such piece is a sight knob used on light artillery. At the request of the DND's Director General Nuclear Safety (DGNS-DND's internal nuclear regulatory agency), the authors were contacted to remove the luminous tritium-impregnated paint strip from over 300 sight knobs. This paper discusses the physical description of the sight knobs, the protocol developed for decontaminating the sight knobs, the rationale for the release limits used, and experience gained in using and modifying the decontamination protocol.

Neutron production associated with radiotherapy linear accelerators using intensity modulated radiation therapy mode.

A number of experiments were conducted on a Clinac 21EX radiotherapy accelerator using an IMRT treatment plan to determine neutron dose equivalent as a function of both patient dose delivered and machine workload. It was determined that IMRT mode is more neutron dose intensive as a function of patient dose when compared to a similar standard non-IMRT treatment. It was found that when the neutron production is normalized to workload, the measured neutron dose equivalents are similar. It is therefore recommended that neutron production be reported as a function of workload when considering IMRT treatment modes.