Interaction Mechanism
Broadly speaking, there are two categories of radiation: "ionizing" and "non-ionizing" radiation. Ionizing means the radiation is energetic enough that when it comes into contact with an atom, it can remove an electron from it, thereby ionizing it (giving it a charge). Ionizing radiation can also break chemical bonds, or even damage the nucleus of an atom with enough energy.
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| http://www.arpansa.gov.au/radiationprotection/basics/ion_nonion.cfm |
In terms of biology, ionizing radiation entering a cell may cause harm directly, by smashing into or being absorbed by "macromolecules", e.g. DNA strands, proteins, enzymes.. Damage may also be caused indirectly, through interactions with water creating "free radicals" (ionized atoms) that can go on to damage the macro-molecules [1].
Radiation Treatment of Cancer
So, why is it we use radiation to treat cancer, if it is also a cause of cancer? The answer is primarily that we have no better way, in many cases. Some cancers may be inaccessible to surgeons, or the patient may not be in healthy enough to withstand a surgery.
And how does it work? The same way that radiation damages healthy cells, it can also damaged cancerous cells. The same mechanisms (direct and indirect damage) still apply, and the idea is simply to focus as much radiation on the tumor as possible for a long enough time to destroy all the cells causing the cancerous tumor.
And how does it work? The same way that radiation damages healthy cells, it can also damaged cancerous cells. The same mechanisms (direct and indirect damage) still apply, and the idea is simply to focus as much radiation on the tumor as possible for a long enough time to destroy all the cells causing the cancerous tumor.
Unfortunately, while we have methodologies to make the maximum energy (radiation damage) be deposited in the tumor site, the radiation must also damage healthy cells in its path. This may cause a sunburn-like reddening of the skin at the entrance and exit of the radiation area, or, if the treatment is intensive enough, overall radiation sickness may occur. Radiation sickness is what many picture when they think of radiation treatment, and involves fatigue, nausea, hair loss and other symptoms.
Additionally, there is always a random (stochastic) chance that the healthy cells damaged along the way to healing the cancerous tumor may also eventually develop into cancerous cells themselves.
[1] http://www.ehs.msu.edu/radiation/programs_guidelines/radmanual/14rm_bioeffects.htm
Elaborating on what you've presented concerning why we use radiation in a clinical setting to treat cancer: Although radiation therapy is the only available treatment for most types of cancer, there are studies that show selective attack by wasp venom on cancer cells. The intriguing aside is that no normal cells are harmed as a result of injection. Drugs that attack the lipid composition of the cell membrane may be a new means by which we combat the tragedy that is cancer.
ReplyDeletehttp://phys.org/news/2015-09-brazilian-wasp-venom-cancer-cells.html
That's actually really cool. About time a positive thing was found about wasps. They still scare me, though. Did you know there is a wasp that lays its eggs in a live spider? It hatches and eats the live spider inside out. Sorry for that image.
DeleteI digress. The article is cool, and I don't understand cellular biology enough to know what they're talking about when they describe the difference between cancerous vs healthy cellular membranes. The "phospholipids" face inwards instead of outwards and so the venom can act on them?