at once???..... Why ? why not? Will new cells regenerate from where the cells were killed? why? why not? how?
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No, it doesn't really work that way. X-rays and CT scans (which use X-rays) damage DNA. The actual amount of X-rays is pretty low, so any damage they cause is easily repaired by our cells. The amount of damage that is caused by the environment is larger than that of a single medical X-ray (and I don't just mean from pollution - the planet has been bombarded by radiation from space since before even the first life appeared).
If you were to receive a much higher dose of X-rays, then it might cause more damage than your body can handle. The thing is, it's most dangerous to cells that are either dividing or just about to divide. The mechanisms that sense DNA damage are tightly linked to the cell cycle - if the cell is copying its DNA, and it detects a big enough problem, it will either halt the cell cycle to give time to repair, or it will self-destruct. While this is bad for rapidly-dividing cells like skin cells or blood cells, it also makes rapidly-dividing cancer cells vulnerable. It doesn't kill newborn cells, though - only ones that are dividing a lot (of which there are actually fewer cells than you might think).
Provided that it isn't a truly massive dose of radiation (i.e. a fatal dose), then the surviving cells will regenerate the lost ones. It may take a while, and you might temporarily lose your hair, develop sores, and suffer from weakness, but you can recover.
If you were to receive a much higher dose of X-rays, then it might cause more damage than your body can handle. The thing is, it's most dangerous to cells that are either dividing or just about to divide. The mechanisms that sense DNA damage are tightly linked to the cell cycle - if the cell is copying its DNA, and it detects a big enough problem, it will either halt the cell cycle to give time to repair, or it will self-destruct. While this is bad for rapidly-dividing cells like skin cells or blood cells, it also makes rapidly-dividing cancer cells vulnerable. It doesn't kill newborn cells, though - only ones that are dividing a lot (of which there are actually fewer cells than you might think).
Provided that it isn't a truly massive dose of radiation (i.e. a fatal dose), then the surviving cells will regenerate the lost ones. It may take a while, and you might temporarily lose your hair, develop sores, and suffer from weakness, but you can recover.
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The high energy waves, x-rays, could damage the cells but they can also damage the DNA which causes mutations during cell division.
Whereas MRI scans use low energy radio waves, and ultrasounds use very high frequency sound waves, both of which have been deemed safe by medical professionals
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Whereas MRI scans use low energy radio waves, and ultrasounds use very high frequency sound waves, both of which have been deemed safe by medical professionals
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