After giving the radioactive product,the brain emits gamma rays which were measure with the help of geiger counter.the measurement were done one hour after the injection and after 24 this difference in the measurement is useful in diagnosing the brain tumors.
When injected into your blood radioisotopes will illuminate your blood vessels under an X-ray. This is what allows doctors to see blockages and deformities in the blood vessels. Because tumors are typically highly vascular, meaning they contain a lot of blood vessels, I expect that radioisotopes can help brain surgeons see tumors in the brain just as they could to see a blockage in the heart from the lack of radioisotope in one area of the heart.

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