17.5 Decorporation of Internal Radionuclides
209
those exposed to Cs-137 during the accident in Goiânia Brazil increased the Cs-137
excretion by a factor of three with a concomitant reduction in radiation exposure to
those receiving the medication [9].
The process of removing internal radioactivity is called decorporation and there
are a number of agents that can be used to decorporate many radionuclides to which a
person might be exposed. It must be noted that a decorporation agent will act against
all nuclides of a given element, not only against those that are radioactive. Thus, if
a person had an uptake of, say, radioactive cobalt and a decorporation agent were
administered, it would act to scavenge both radioactive cobalt to which a person had
been exposed as well as the stable cobalt present in the heart, liver, pancreas, that is
used in the synthesis of Vitamin B
12 and any of a number of proteins and enzymes
used throughout the body. Because all cobalt isotopes are chemically identical, it is
not possible to decorporate only the radioactive isotopes.
Some decorporation agents are so simple to administer that this can be done by
the patients themselves. Potassium iodide (KI), for example, can be provided in
advance of any exposure and the administration instructions can easily be printed
on the side of the bottle of tablets [26]. In fact, many states in the US pass out KI
to all citizens living within a given distance of a nuclear power plant so that, in the
event of a meltdown, public health officials can order everybody to take the KI they
have at their homes. Potassium ferrocyanide (Prussian blue), a compound that would
be taken after exposure to radioactive cesium, is also relatively easy to administer
and capsules can be taken by patients. These are also safe enough that, even if the
patients accidentally misadminister the medication, they are likely to be unharmed.
Other decorporation agents are either more difficult to administer or must be
administered more carefully to avoid toxicity concerns. Diethylenetriamine pentaacetate (DTPA), for example, is typically administered intravenously and can cause
chills, diarrhea, fever, and other effects; it can also scavenge zinc from the body,
requiring zinc supplements [29]. As if that were not enough, there are different forms
of DTPA—calcium and zinc—each with its own requirements and precautions for
administration. The Food and Drug Administration also recommends caution when
administering Ca-DTPA to patients with hemochromatosis (a rare genetic condition that affects the manner in which our bodies process iron). As a more complex
medication, DTPA requires more care and more skill from those prescribing and
administering it; unlike KI, we cannot hand out DTPA in advance or in anticipation
of an accident or attack.
Other documents (e.g. [10, 24, 25, 29]) go into detail with regards to dosing,
counterindications, precautions, and the like and those will not be repeated here.
Table 17.3 was developed using information from the references above and provides
a summary of some relevant information for a number of medical countermeasures,
but it is not intended to be comprehensive. Decorporation is a part of the overall
medical management of patients that have ingested or inhaled radioactive materials,
and it must be coordinated with the medical personnel attending to the patient’s other
injuries [5].
209
those exposed to Cs-137 during the accident in Goiânia Brazil increased the Cs-137
excretion by a factor of three with a concomitant reduction in radiation exposure to
those receiving the medication [9].
The process of removing internal radioactivity is called decorporation and there
are a number of agents that can be used to decorporate many radionuclides to which a
person might be exposed. It must be noted that a decorporation agent will act against
all nuclides of a given element, not only against those that are radioactive. Thus, if
a person had an uptake of, say, radioactive cobalt and a decorporation agent were
administered, it would act to scavenge both radioactive cobalt to which a person had
been exposed as well as the stable cobalt present in the heart, liver, pancreas, that is
used in the synthesis of Vitamin B
12 and any of a number of proteins and enzymes
used throughout the body. Because all cobalt isotopes are chemically identical, it is
not possible to decorporate only the radioactive isotopes.
Some decorporation agents are so simple to administer that this can be done by
the patients themselves. Potassium iodide (KI), for example, can be provided in
advance of any exposure and the administration instructions can easily be printed
on the side of the bottle of tablets [26]. In fact, many states in the US pass out KI
to all citizens living within a given distance of a nuclear power plant so that, in the
event of a meltdown, public health officials can order everybody to take the KI they
have at their homes. Potassium ferrocyanide (Prussian blue), a compound that would
be taken after exposure to radioactive cesium, is also relatively easy to administer
and capsules can be taken by patients. These are also safe enough that, even if the
patients accidentally misadminister the medication, they are likely to be unharmed.
Other decorporation agents are either more difficult to administer or must be
administered more carefully to avoid toxicity concerns. Diethylenetriamine pentaacetate (DTPA), for example, is typically administered intravenously and can cause
chills, diarrhea, fever, and other effects; it can also scavenge zinc from the body,
requiring zinc supplements [29]. As if that were not enough, there are different forms
of DTPA—calcium and zinc—each with its own requirements and precautions for
administration. The Food and Drug Administration also recommends caution when
administering Ca-DTPA to patients with hemochromatosis (a rare genetic condition that affects the manner in which our bodies process iron). As a more complex
medication, DTPA requires more care and more skill from those prescribing and
administering it; unlike KI, we cannot hand out DTPA in advance or in anticipation
of an accident or attack.
Other documents (e.g. [10, 24, 25, 29]) go into detail with regards to dosing,
counterindications, precautions, and the like and those will not be repeated here.
Table 17.3 was developed using information from the references above and provides
a summary of some relevant information for a number of medical countermeasures,
but it is not intended to be comprehensive. Decorporation is a part of the overall
medical management of patients that have ingested or inhaled radioactive materials,
and it must be coordinated with the medical personnel attending to the patient’s other
injuries [5].