radioactive materials is accomplished by treating the patient in a single location, controlling access to that location, and by using standard contact precautions Internal contamination Internal contamination can be a serious problem because it is difficult to eliminate some long-lived radioactive materials from within the body Death due to radiation from internal contamination is rare A few deaths have been caused by medical misadministrations A familiar example of intentional, nonlethal internal contamination is the bone scan performed in a nuclear medicine department Treatment of hyperthyroidism with 131I (radioactive iodine) also is, in a sense, planned internal contamination Metal fragment Another source of possible contamination is the radioactive metallic fragment, which can be intensely radioactive These could, in principle, be found if a “dirty bomb” was constructed with a radioactive metal source such as 192Ir (radioactive iridium) Radioactive metal fragments can be embedded in the patient’s skin and should never be touched with the examiner’s fingers Tongs or forceps will increase the distance between the radioactive metal fragment and the fingers, and thus greatly reduce any radiation dose to the healthcare worker Hot particles “Hot” particles are microscopic particles that can be highly radioactive Typically, they contain 60Co (radioactive cobalt) or other fission products and might be found on a nuclear reactor worker after a reactor accident These particles can be difficult to localize and remove and may give a large radiation dose to a small volume of tissues If the particle is trapped under a nail or is in the fold of the skin, routine washings may not dislodge it The particle can sometimes be localized by using a thick piece of lead If the lead is placed between the particle and the radiation detector, the exposure rate should decrease substantially Once the particle is localized, it can usually be removed by using simple mechanical means Rarely, a punch biopsy of the skin may be necessary Terrorist events Nuclear materials may be used intentionally in a terrorist event An intact sealed source could be placed in a populated area, generating whole-body exposures but no contamination A conventional explosive combined with radioactive materials, the so-called “dirty bomb,” could be employed to disseminate radioactive materials over an area Victims of such an attack would likely have radiation exposure as well as injuries from the explosion itself An attack on a research or commercial power reactor could produce a large-scale dispersion of nuclear material; victims could be exposed to whole-body and localized radiation, as well as internal and external contamination Transported nuclear materials such as radiopharmaceuticals or radioactive waste could be the subject of a terrorist attack The effects would vary depending on whether the containers were breached—intact containers would produce only potential