Upload
denis-little
View
217
Download
1
Embed Size (px)
Citation preview
Medical Procedures – Ionizing
– X-Ray– CT Scan (Computed
Tomography)– Nuclear Medicine
Medical Procedures – Non-Ionizing
– Ultrasound– MRI (Magnetic Resonance
Imaging)
1
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.
2
Beneficial Uses of Radiation
Question:– What is required in order
for a radioisotope to be useful as tracers in nuclear medicine?
3
Beneficial Uses of Radiation
Answer:A radioisotope must be important in body processes and accumulate in the organism being studied.
4
Beneficial Uses of Radiation
5
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.
6
Beneficial Uses of Radiation
7
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