Overview of Radioactivity

The spontaneous emission of nuclear radiation from the nucleus of an atom, usually alpha or beta particles, often accompanied by gamma rays.

Atoms with unstable nuclei that undergo radioactive decay.

The forces holding the nucleus together are weaker than the forces disrupting it.

Alpha particles are made of two protons and two neutrons. Beta particles are high-energy electrons (or positrons). Gamma rays are high-energy photons.

Alpha decay, Beta decay, Gamma decay.

A type of radioactive decay in which a neutron in the nucleus decays into a proton, an electron (beta particle), and an antineutrino.

A particle with no charge and nearly zero mass, emitted during beta decay. It interacts very weakly with matter.

A type of radioactive decay in which an excited nucleus emits a high-energy photon, called a gamma ray, to return to a lower energy state.

An atom with the same atomic number but different energy levels. Often formed after alpha or beta decay.

A high-energy photon emitted during gamma decay, traveling at the speed of light. One of the most energetic forms of electromagnetic radiation.

The process of an unstable nucleus transforming into a stable form by emitting particles or energy. Also known as 'nuclear transformation' or 'radioactive decay'.

An atom with an unstable nucleus that undergoes radioactive disintegration. It's also referred to as a 'radionuclide' or 'radioisotope'.

A type of radioactive decay where an unstable nucleus emits an alpha particle (two protons and two neutrons).

A heavy, slow-moving particle consisting of two protons and two neutrons, emitted during alpha decay.

The resulting nucleus after an alpha decay, which is lighter than the original nucleus.

The nucleus that undergoes radioactive decay, for example, undergoing alpha decay.

High-energy electrons or positrons emitted during beta decay.

A type of radioactive decay where an unstable nucleus captures an inner-shell electron, resulting in the emission of a gamma ray.

High-energy electromagnetic radiation emitted during different types of radioactive decay, including electron capture and gamma decay.

Beta particles are emitted from nuclei that have too many neutrons for stability. This occurs when a neutron in the nucleus decays into a proton and an electron, releasing an electron (beta minus) and a proton which rejoins the nucleus.

Beta particles are emitted from nuclei that have too many protons for stability. This occurs when a proton in the nucleus decays into a neutron and a positron, releasing a positron (beta plus) and a neutron which rejoins the nucleus.

The energy that a particle can deposit in living tissue. It can cause significant damage to cells.

Measure of the radiation energy deposited in living tissue per unit mass. It's the energy absorbed by the tissue.

A measure of the radiation energy deposited per unit mass of a material while considering the specific type of radiation and the biological effectiveness of the radiation.

Radiation that can penetrate a few centimeters of tissue and cause skin reddening or erythema.

The emission of negatively charged beta particles. This occurs when a neutron in the nucleus decays into a proton and an electron.

The process of using a gamma camera to measure the amount of a radioactive substance absorbed in different parts of the body.

Technetium-99m is a common radioactive isotope used in medical imaging, especially bone scans. It has a half-life of 6 hours, which means its radioactivity decreases by half every six hours.

A bone scan often combines the images from a gamma camera with those from a CT scan to provide a more comprehensive picture of bone health.

The effective half-life is the time it takes for the amount of a radioactive substance in the body to reduce by half due to a combination of radioactive decay and biological elimination processes.

Calculating the amount of radioactive substance remaining at a given time is done using the formula A = A0 / (2^N) where A is the activity at a given time, A0 is the initial activity, and N is the number of half-lives that have passed since the initial activity.

The time taken for the activity of a radioactive substance to decrease to half its initial value. It's a constant for each radionuclide.

The number of radioactive decays per unit time. It's how we measure the 'strength' of a radioactive sample.

Activity per unit mass of a radioactive substance. It's a useful way to compare how 'radioactive' different materials are.

The probability that a radioactive nucleus will decay in a given time period. It's a key factor in understanding radioactive decay.

A curve that shows the gradual decrease of radioactivity over time for a specific radionuclide.

A radioactive substance used in nuclear medicine to image the body and analyze physiological processes.

A branch of medicine that uses radioactive substances to diagnose and treat diseases.

A process that involves using radioactive substances to create images of the inside of the body.