### energy | radiation:

Internal radiation
* involves implanting radioactive materials in the part of the body to be treated.
* uses radioactive pellets placed directly into the prostate gland.

### energy | radiation:

Ionizing radiation
* appears to be a poor point mutagen.
* can be electromagnetic radiation or subatomic particles.
* can cause changes in the chemical balance of cells
  - extensive damage to biological tissues
  - genetic defects
  - change the chemical composition of many things, including living tissue
  - destroy molecules by breaking the bonds which hold the atoms together
  - penetrate cells and create ions in the cell contents
* causes atoms and molecules to become ionized or excited
  - biochemical oxidation of free radicals in cells
  - damage to hereditary structures
  - the formation of free radicals in the body
* comes from natural sources such as radioactive elements in soil or bedrock.
* consists of gamma particles which strip electrons from atoms.
* emitted by californium on bone and in the liver can cause cancer.
* frequent cause, but some chemicals produce breaks as well.
* has enough energy to change normal cellular functioning
  - remove an electron from an atom
  - the potential to damage living tissue
* induces expression of immediate early genes in the rat brain
  - gene mutations in a wide variety of cellular systems
  - mitochondrial gene expression and activity
* is and always has been a natural part of our environment
  - directly proportional to effective dose equiva-lent
  - emitted, including beta and gamma radiation
  - good treatment for nonsurgical candidates with facial tumors
  - harmful
  - hypothesized to kill cancer cells by breaking DNA bonds
  - known to cause cancer and other adverse human health effects
  - located in space
  - necessary to penetrate solid or light-absorbing materials
  - one of the mainstays of modern oncology
  - produced by unstable atoms
  - ubiquitous in our everyday lives
  - very effective for sterilization and decontamination
* is, in fact, the only well-established cause of brain tumors.
* kills blood cells.
* known cause of cancer and other adverse effects
* modulates the spread of an apathogenic rabies virus in mouse brain.
* passes through food in the form of radiant energy, without leaving any residue.
* proven cause of human cancer.
* safe and effective food preservation tool.
* well known human and animals teratogen.
* well-established risk factor for brain tumors.
* works by damaging the DNA of exposed tissue thus killing it.
+ Radiation therapy: Cancer treatment
  * Radiation therapy is used on tumors because of its ability to control cell growth. Ionizing radiation works by damaging the DNA of exposed tissue thus killing it. Besides the tumor itself, the target for the radiation may also include the lymph nodes that drain the area. Doctors include the lymph nodes if they are clinically or radiologically involved with tumor, or if there is thought to be a risk of that individual cancer cells will spread. It is impossible to aim the radiation beam exactly because the tumor moves as the patient breathes. So, doctors also expect to include some heathly tissue around the tumor to make sure that the entire turmor is hit by radiation.

Laser radiation
* can cause injury to the eyes and the skin.
* has a correcting effect on lipid exchange.
* is coherent and confined to a very narrow beam.