Radiation

Radiation is energy sometimes produced by materials and sometimes by physical interactions, such as the contact of matter with anti-matter.

Biological effects
Radiation is often harmful or fatal to most life and can cause mutations. Some organisms can withstand large amounts of radiation, such as the Foamasi (DW: The Leisure Hive). Also, Time Lords had the ability to absorb, withstand, and expel large amounts of certain types of radiation, as stated by the Tenth Doctor, they used to play with Röntgen bricks in the nursery. (DW: Smith and Jones) Others could actually absorb and regenerate with it, such as the Kastrians (DW: The Hand of Fear) or beings such as the Daleks on Skaro, whose evolution led (at various points) to them becoming dependent on a constant supply of radiation. (DW: The Daleks) Similarly, an Exxilon fuel pod was left in ancient Earth Incan civilization causing mutations in the populace and leading to Huitzilin gaining massive powers. (NA: The Left-Handed Hummingbird) The Solonians used thaesium radiation to cause the "mutations" that were part of their life cycle. (DW: The Mutants)

Radioactive locations

 * Argolis had a radioactive atmosphere as a result of a nuclear war with the Foamasi. (DW: The Leisure Hive)
 * On the planet Janus Prime, the radiation on the planet made its sand glow blue, it also destroyed a (human) body's lipids, making skin sticky to the touch until it turned into jelly-like in texture. Upon death, the body lost cohesion and collapsed into a porridge-like substance. (EDA: The Janus Conjunction)
 * Romana and The Doctor suffer from radiation on Skaro and Romana, to escape the Daleks clasp, fakes dying due to radiation. (DW: Destiny of the Daleks)
 * Messaline had a relatively high level of radiation; this was however eradicated via terraforming methods. (DW: The Doctor's Daughter)
 * Oseidon had the highest radiation level in the galaxy of Mutter's Spiral. (DW: The Android Invasion)
 * The Petrified Forest of Skaro had a high radiation level as a result of a past nuclear war between the Thals and the ancestors of the Daleks. (DW: The Daleks)
 * The Third Doctor regenerated due to radiation exposure on Metebelis III. (DW: Planet of the Spiders)
 * The Tenth Doctor regenerated due to radiation exposure, taking the place of Wilfred Mott. (DW: The End of Time)