I read about cancer treatment where the patient would be given radiation to kill cancer cells. How do they make sure that it affects mostly the cancer cells? Moreover how do they manage it so that it kills cancer cells but does not causes more cancer by radiation poisoning.
https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy/radiation-fact-sheet The quick answer is the healthy cells do get radiations (you may read more info on the above link), but they came up with a clever idea on how to minimalize the radiation absorbed by healthy cells but at the same time give a lot of radiation to the cancer cells. Look at this video from 1:44. https://youtu.be/_moypMx05Fw Simply enough, they used computer to analyze 3D picture of your body, then "shoots" the cancer cells from different angles so that the healthy cells get minimum damage. This doesn't relate to the question but maybe you want to know that cancer cells are weaker than normal cells because they are too busy growing and less organized that normal cells which makes them harder to recover from the radiation. That makes things a lot easier. This is link to the proof. http://www.breastcancer.org/treatment/radiation/how_works
It doesn't. They focus the radiation on mostly cancer, from different angles. The radiation only kills cells in the process of splitting ; because the cancer cells are growing faster , they split more often. So the radiation kills a higher proportion of cancer cells than normal cells. The plan is when all the cancer cells have been killed there will not be extensive damage to normal cells and they can recover, sort of. In my case 98% of the beard hair follicles cells were killed so I will never have a beard. A downside is the normal cells that survive now develop fibrosis in reaction to the radiation.