The substance used for bone scans is taken out of the blood by bone-forming cells, and concentrates especially in areas where the bone cells are very active. In this type of scan, abnormalities show up not as ‘holes’ but as ‘hot spots’—areas where more than the usual amount of radioactive substance collects. This is because bone cells are especially active around abnormalities such as fractures, infections, or cancer deposits. The scan picks up the problem indirectly by showing the bone cell reaction rather than the abnormality itself. The amount of radiation involved in taking a scan of all the bones in the body is actually quite a bit less than if all those bones were X-rayed.
Various radio-isotopic methods can be used to get ‘pictures’ of most organs. For different organs we use different substances, choosing one that will be concentrated in the particular organ we wish to study. In all cases the radioactivity does not stay in the body for long. It is passed out through the urine, faeces or air from our lungs. The amount of radioactivity involved in each test is very small, and doesn’t pose any danger to anyone you go near or touch. If you want exact details, ask the people who are doing the test. They should tell you how long it takes your body to get rid of the particular substance being used and which way it is eliminated.
One drawback with these tests is that you only ‘see’ the parts of the organ that are functioning normally. The ‘holes’ or ‘hot spots’ can be due to any one of many things that interfere with that organ’s function. Cancer is only one of many possible reasons for abnormalities in these scans.
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Tags: Cancer