Radioisotopic Labelling
To Study the Function of Internal Organs
What is an Isotope?
- An isotope is 2 or more elements with the same amount of protons, but different amount of neutrons
- For ex. Carbon 12 and Carbon 13 are both isotopes of carbon, one with 6 neutrons and one with 7 neutrons
- Isotopes do not emit rays that can be seen through a machine
- They are short lived because of their half lives
What is a Radioisotope?
- A Radioactive Isotope is an unstable isotope
- They are radioactive and emit alpha, beta and gamma rays
- They help diagnose deformities in organs by showing the shape of the organ, as well as detecting heat in the organ
- Can be used as a poison which can kill (In 2006 Britain witnessed the apparent murder of one of its newer citizens, a former Russian intelligence official, by poisoning with radioactive polonium. His death was slow and excruciating.)
Alpha Rays
- Very fast, large particles that are emitted during the decay of radioactive substances
- Has a low penetrating power, so can be stopped with a sheet of paper
- Has the same weight as an electron
- Very light particle
- Has a medium penetrating power, takes a aluminum to stop it
- Is a wave and burst of energy, not a particle
- Has a high penetrating power
- Takes a thicker sheet of metal to reduce (ex; lead or concrete)
Most Common Radioisotope: Radionuclide/Radioactive Nuclide
- An atom with an unstable nucleus, characterized by excess energy
- Emit nuclear energy; specifically gamma rays
- When a radionuclide decays its presence can be detected by the radiation it emits, thus assisting in radiotherapy
- Technetium-99m(Tc) [used to identify impeded blood flow to the heart or spread of cancer to the bones]
- Cadmium-109(Cd) [used to detect cancer]
- Europium-155(Eu) [osteoporosis detection]
- There are numerous radioisotopes
Advantages
- Travels fast through the body, some as fast as the speed of light
- A quick way to find a serious problem in the body
- Elements have a huge amount of energy inside, so don't use up quickly
- Detect cancer (one of the leading causes of death)
- Radiotherapy can weaken or destroy particular cells in diseases like cancer
Disadvantages
- Very dangerous
- Can cause infertility
- Radioisotopes can cause cancer if exposed in high doses, therefore shouldn't be exposed in high doses
Positron Emission Tomography (P.E.T)
- A more precise and sophisticated technology that uses isotopes produced in a cyclotron [a type of compact particle accelerator used to produce quantities of radioactive isotopes called positron emitters]
- A radionuclide is introduced as it accumulates in the target tissue
- It then decays and emits a positron [a subatomic particle with the same mass as an electron and a numerically equal but positive charge]
- This process makes it easy to detect the presence or absence of radioactive materials even when in low concentration