Radiation

Destroy tumors, cure cancer, relieve symptoms, and prevent tumor growth or spread.

Can damage healthy tissues, may cause side effects during therapy, and increase the risk of secondary cancers later.

There is no safe level of radiation; even small doses may pose risks, with likelihood of harm rising with higher doses.

There is a threshold for effects, which increase in severity with dose, potentially causing cell death and tissue damage.

Radiation directly ionizes DNA or other molecules and damages cells immediately.

Radiation hits water, creating free radicals that attack DNA and other cell structures.

DNA, as it controls cell division and function, leading to mutations, cancer, or cell death.

The amount of radiation energy absorbed by a material, calculated as D=E/m.

The energy deposited per unit length of tissue, with high LET causing more biological damage.

It compares how damaging one type of radiation is relative to a reference, often X-rays.

During mitosis, with G2 being very sensitive and late S being most resistant.

Repair, Reassortment, Repopulation, Reoxygenation.

Normal cell damage is repaired.

Cancer cells shift to a sensitive cell cycle phase.

Normal tissues regrow, but tumors can also regrow if treatment is too slow.

Oxygen levels rise as tumors shrink, making the tumor more sensitive.

Prodromal, Latent, Manifestations, Recovery or death.

Onset of nausea, vomiting, and diarrhea after minutes/hours.

No symptoms after hours/days, but bone marrow suppression starts.

Multiple organ symptoms appear after weeks.

Death often from sepsis, with no recovery after weeks or more.

High-energy radiation that can ionize atoms.

Direct hits atoms directly, while indirect creates free radicals from water.

A helium nucleus consisting of 2 protons and 2 neutrons, with low penetration ability.

High-energy electrons or positrons, with two types: beta-minus and beta-plus.

High-energy photons released when a nucleus drops from a high-energy state to a lower one.

Neutrons.

The number of decays happening per second in Becquerel (Bq).

Electrons are emitted from a heated cathode, accelerated towards a metal anode, and some energy becomes X-ray photons.

A particle and its antiparticle collide, both are destroyed, and their energy becomes two photons (gamma rays).

High-energy particles (mostly protons) from space that travel near the speed of light, originating from the sun, distant galaxies, and supernovae.

To understand how radiation loses energy in matter.

The reduction of radiation as it passes through matter, caused by absorption and scattering.

The probability that a photon will be removed per unit distance.

A photon hits an inner-shell electron, transfers all its energy, and ejects the electron, used in X-ray imaging.

A photon hits a loosely bound outer electron, is scattered, loses energy, and ejects the electron.

A photon interacts with the nucleus and creates an electron and positron, dominant at high energy, happens in PET scans.

They directly ionize matter via Coulomb forces, leading to excitation or ionization.

To measure ionization of gas inside a tube.

Precise dose measurement of radiation.

To detect the presence of radiation.

They detect a light flash (scintillation).

It darkens when exposed to radiation.

Radiation is passed through the body, with dense tissues absorbing more radiation and appearing white, while soft tissues absorb less and appear black or dark.

Cross-sectional (slice) images of the body from X-rays taken at multiple angles.

It detects gamma rays emitted from a radioactive tracer to show an organ's function and structure.

SPECT provides 3D imaging by collecting many 2D images with a rotating gamma camera.

It uses positron-emitting tracers that emit two photons when a positron meets an electron, which are detected together for metabolic activity observation.

It uses sound waves sent and received by a probe with piezoelectric crystals.

A-mode (1D depth), B-mode (2D image), and M-mode (1D animation for moving organs).

It uses a strong magnetic field and radio waves to target hydrogen nuclei in tissues, emitting signals as protons realign.

To treat cancer with radiation from outside the body.

They are low-energy X-rays used for benign diseases and shallow cancers, penetrating only 4-6 cm into tissue.

They accelerate electrons using microwaves to produce high-energy X-rays for deep tumors and electron beams for surface tumors.

A form of internal radiation therapy where small, radioactive seeds are placed inside or near the tumor.

Temporary (removed after a few hours/days) and permanent (left in the body, decays over time).

It targets the thyroid gland and is used in hyperthyroidism and thyroid cancer.

It targets and is used in liver tumors.

They target bones and are used to relieve pain in bone metastases.

Wilhelm Röntgen.

Radioactivity.

Isolated radioactive elements and won Nobel Prizes in Physics and Chemistry.

The 'plum-pudding' atomic model.

The concept of half-life.

E = mc².

The quantum model of the atom, where electron orbits are quantized.

The neutron.

An atom consists of a nucleus and an electron cloud.

A neutral atom has an equal number of protons and electrons.

Protons (positive, in the nucleus), neutrons (neutral, in the nucleus), and electrons (negative, in the electron cloud).

Electrons are in the lowest energy levels, stable, and shown in the periodic table.

Electrons absorb energy and jump to higher energy levels, becoming unstable and temporary.

It states that electrons act like waves.

You cannot know the exact position and momentum of an electron at the same time.

Principal (n), Angular (l), Magnetic (ml), Spin (ms).

No two electrons in an atom have the exact same four quantum numbers.

Z protons and (A-Z) neutrons, where Z is the atomic number and A is the mass number.

A nucleon is a proton or neutron.

The strong nuclear force.

All matter has a wavelength, explaining wave-like behavior of electrons.

An atom that gains an electron and becomes more negative.

An atom that loses an electron and becomes more positive.

Atomic mass units (amu).

The average mass of all naturally occurring isotopes of an element weighted by abundance.

6.02 x 10^23 particles, based on the number of atoms in 12g of carbon-12.

W = charge x voltage (W = q x V).

The energy gained by 1 electron moving across 1 volt; standard energy unit in atomic/nuclear physics.

1 eV = 1.602 x 10^(-19) J.

Coulomb force.

A powerful attraction between nucleons (protons and neutrons).

Because they require interaction with protons to form stable pairs.

The process where a very heavy atom, like uranium, splits on its own, producing smaller atoms and releasing 2-4 neutrons.

By triggering the splitting of heavy atoms like uranium to release heat for electricity generation.

The process where two light atoms combine to form a heavier atom, releasing significantly more energy than fission.

Because it requires extremely high temperatures and pressures.

Electrons released from one split cause the next split, continuing the reaction.