Medical Procedures – Ionizing

– X-Ray– CT Scan (Computed

Tomography)– Nuclear Medicine

Medical Procedures – Non-Ionizing

– Ultrasound– MRI (Magnetic Resonance

Imaging)

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Beneficial Uses of Radiation

- Because the element iodine accumulates in the thyroid, the radioisotope Iodine-131 can be used to diagnose thyroid problems.

- As Iodine-131 atoms are absorbed by the thyroid, their nuclei decay, emitting beta particles and gamma rays.

- The beta particles are absorbed by the surrounding tissues, but the gamma rays penetrate the skin. - The emitted gamma rays can be detected and used to determine whether the thyroid is healthy.

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Beneficial Uses of Radiation

Question:– What is required in order

for a radioisotope to be useful as tracers in nuclear medicine?

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Beneficial Uses of Radiation

Answer:A radioisotope must be important in body processes and accumulate in the organism being studied.

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Beneficial Uses of Radiation

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Museums and archeologists rely on radiation detection to verify the authenticity or age of art objects or archeological findsRadiocarbon decays at a known rate. Paleontologists are able to determine the age of a fossil by measuring the amount of C-14 it contains.

FossilA small piece of the fossil is

burned and converted to carbon dioxide gas.

Unstable C-14

Stable C-12

Nitrogen

Electron

Living organisms absorbC-14 (radiocarbon) during

their lifetimes

A radiation counterrecords the number of electrons emitted

C-14 decaysinto N-14 emitting

an electron

Beneficial Uses of Radiation

Radioactive Half-Life & Radioactive Dating: – Half-lives vary widely

among the radioactive isotopes.

– The half-lives of some radioactive elements are listed in the table.

– The ages of rocks and fossils can be determined using radioactive isotopes and their half-lives.

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Beneficial Uses of Radiation

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Radioactive Half-Life: Some radioisotopes decay to stable atoms in less

than a second. A measure of the time required by the nuclei of an

isotope to decay is called the half-life.•

Beneficial Uses of Radiation