A diagnostic tracer of one microcurie of radioactive calcium 45, given orally, would result in an exposure of 3. Therapeutic radiation treatment that is delivered by administering radioactive material via the mouth or by injection usually results in high, very localized doses to a small part of the body, which absorbs most of the radioactivity.
The radioactivity concentrates and remains in the target organ for example, the thyroid for a longer period of time than does the radioactivity that is distributed to the rest of the body.
The radiation exposure for other parts of the body is a function of the amount of radioactivity per pound and the time the radioactivity is present in the tissue. For example, a hyperthyroid problem such as that experienced by former President George Bush is typically treated with a radioactive iodine drink designed to deliver about 10,, millirems of radioactive iodine to the thyroid.
It would coincidentally deliver a dose to the rest of the body of about 20, millirems. A slightly lower dose of radioactivity is used for cancerous tumors.
Radiation to kill a cancerous tumor often involves a beam delivering 6,, millirems to the cancerous tissue, but the whole-body equivalent dose is much less, as it was in the thyroid example cited above.
What is a lethal dose from a single instance of radiation? According to studies made after the atomic bomb explosions in at Hiroshima and Nagasaki, half of the people died whose entire bodies were exposed to , millirems of radiation from the atomic bomb. All persons died whose bodies were exposed to , millirems of radiation. This also was the annual occupational limit for adults from World War II through Limit changed in to 5, millirems.
It is "as low as reasonably achievable; however, not to exceed 5, millirems. An embryo or a fetus of a pregnant worker exposed to radiation a new regulation as of Jan.
Potassium is an essential dietary element that is present mostly in the muscles. A localized dose delivers 10,, millirems to the thyroid and about 20, millirems to the rest of the body. A radiation dose to kill a cancerous tumor often sends a beam delivering 6,, millirems to the cancerous tissue, but the whole body equivalent dose is much less, as in the thyroid case.
The research showed iron supplements are more effective if not be taken with meals. The study used radioactive calcium 45 to track calcium absorption. One adult age 21 was also in the study and received a higher dose, resulting in an exposure equal to 11 millirems for the whole body. A typical X-ray exposes the chest to a dose equal to 20 millirems at the entrance and 1 milliRem at the exit.
Averaging this exposure over the whole body yields a whole body equivalent of about 2 millirems. The US Food and Drug Administration's current regulations state, "The amount of radioactive material to be administered shall be such that the subject receives the smallest radiation dose with which it is practical to perform the study without jeopardizing the benefits to be obtained by the study.
For example, the human body has an activity of Bq — a value which may seem high but is in reality very small. It corresponds a few microcuries. Seeing activities written down in becquerels often gives the impression that such activities are exceptionally high and thus very dangerous. This is mainly due to the small value of a Becquerel, and substances are rarely that dangerous.
The Becquerel is like the Deutschmark used by the Weimar republic in the s when a wheelbarrow full of which was needed to buy a croissant. In the rational and cartesian countries lof the western world, it was logical to define the basic unit of activity as one disintegration per second.
But men of science could be awkward psychologists. The choice of the becquerel has revealed itself to be a public relations disaster. The tiniest levels of activity expressed in becquerels are represented by tremendously high numbers, which feed the insecurity of the public.
Access to page in french. A sealed microcurie source could be safely handled. Improve this question. Community Bot 1. Jonathan Lam Jonathan Lam 1 1 gold badge 6 6 silver badges 20 20 bronze badges. Add a comment. Active Oldest Votes. Improve this answer. Thanks for the explanation!
You told me the effects if you stand so close- but what could have a similar effect? Except at very high levels, radiation exposure isn't immediately noticeable. If we're talking about. I could only speculate what that exposure actually feels like.
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