24.4. Applications of Radioactivity http://www.ck12.org
Figure24.17 shows the accumulation of radioactive compounds that bind to dopamine receptors. The non-addicted
individuals have large numbers of receptors for dopamine. The addicted persons show less binding to these receptors,
indicating that fewer receptors are present.
Lesson Summary
- Everyone is exposed to low amounts of background radiation from medical procedures and naturally occurring
radioactive substances. - Radioactive emissions can alter the structure of DNA, which can sometimes lead to cell death or even cancer.
- Radioisotopes are widely used in medical diagnosis. These isotopes need to have short half-lives so that they
can be administered in very low doses, thus minimizing damage to cells. - Radioactive isotopes are also used in the treatment of certain diseases, such as cancer. These isotopes are
administered to only the diseased tissue, with the goal of destroying the unhealthy cells. - PET scans are very useful in looking at brain structure and chemistry.
Lesson Review Questions
- How are radioactive materials harmful to cells?
- Why are cancer cells so detrimental in the body?
- Why should radioisotopes given to patients have short half-lives?
- Explain how the radioactive isotope of iodine is used to diagnose and treat thyroid cancer.
- How is Tc-99m used to diagnose bone cancer?
- Why is PET scanning so useful in studying the brain?
Further Reading/Supplementary Links
- Radioisotopes in medicine: http://www.world-nuclear.org/info/inf55.html
- Use of radioisotopes in diagnosis and treatment: http://www.rsc.org/images/essay5_tcm18-17767.pdf
- Positron emission tomography: http://www.radiologyinfo.org/en/info.cfm?pg=pet
Points to Consider
- Can you think of any historical events in which people may have been exposed to dangerous amounts of
radioactivity?