Radiation and human health

In summary: Since they have no charge, they don't ionize much until they slam into an electron. High LET radiation such as alpha particles cause a lot of ionization and if they have enough energy have a large RBE. If this is all wrong I hope that somebody will come along and set us both straight!In summary, the different forms of radiation have varying levels of ionizing and penetrating power. However, when considering the damage they can do to human cells, the type of radiation received and the dose are also important factors. Alpha radiation
  • #1
joeyjo100
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Just been revising radiation for an upcoming exam, and was wondering which form of radiation, [tex]\alpha[/tex], [tex]\beta[/tex] or [tex]\gamma[/tex] is the worst to be exposed to?

Ionising power decreases from alpha to gamma, but penetrating power increases from alpha to gamma. Which is more important when considering how much damage each form can do to human cells?
 
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  • #2
What is exactly being held constant here? Typically, for a given dose (energy deposited per unit mass) the gammas and electrons will have the approximately the same biological response, while the alpha will tend to be more damaging.
 
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  • #3
Your question is too open. You need to have some specifics about how the doses were recieved. If you have alpha or beta radiation striking your skin, its pretty much harmless.
 
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  • #4
Shalis said:
It is short but good efforts that you mention the effect of the Radiation on human body.
But the recent study realize that If you touch your head with Earth These Radiation transfer to earth, just like Muslims do in prayer.

References please. See PF rules.
 
  • #5
Hi there,

Drakkith said:
Your question is too open. You need to have some specifics about how the doses were recieved. If you have alpha or beta radiation striking your skin, its pretty much harmless.

As Drakktih said, the harmfulness of radiation on the human body depends if you are talking about external or internal radiation.

If you are standing next to a radioactive sources, the only real danger comes from the gamma radiation. The alpha and the beta are stopped pretty much by the first layers of skin.

If you inhale or ingest some radioactive materials, then the alpha can start causing serious damage. Although, never neglecting the effects of beta and gamma, the alpha radiation will probably be the most harmful for the body.

Cheers
 
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  • #6
The weighting factors for x-rays, gamma rays, electrons, positrons and muons is 1.
Neutrons range from 2 to 20 depending on their energy.
Alpha particles are 20!

Consequently, alpha radiation is far more dangerous to human health.

X-rays, gamma rays and electrons generally form diffused ions when they strike human cells. Normal healthy cells are well equipped to easily repair such ions.
Alpha radiation on the other hand is between 10 to 1000 times more concentrated and likely to cause chromosome damage; especially if injected or inhaled.

Radon gas (alpha radiation) is the 2nd leading cause of lung cancer while electrons and x-rays can be used to cure a wide variety of cancers.
 
  • #7
Xnn said:
Radon gas (alpha radiation) is the 2nd leading cause of lung cancer while electrons and x-rays can be used to cure a wide variety of cancers.

This statement is very misleading. The rest of your post is fine.Alphas can also be used in radiation therapy. It is exactly the higher ionization that makes it effective.
 
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  • #8
Hi there,

Xnn said:
The weighting factors for x-rays, gamma rays, electrons, positrons and muons is 1.
Neutrons range from 2 to 20 depending on their energy.
Alpha particles are 20!

Alpha radiation from an external source does not penetrate the first layers of the body. How can it be dangerous if it does not penetrate, even with a weighing factor of 20?

Cheers
 
  • #9
fatra2 said:
Hi there,



Alpha radiation from an external source does not penetrate the first layers of the body. How can it be dangerous if it does not penetrate, even with a weighing factor of 20?

Cheers

I believe everyone here is assuming that by "alpha radiation" one means the alpha particle emitted during radioactive decay. The energy typical of these alphas is about 5 MeV. At 5 MeV, an alpha only travels about .004 cm in water (a proxy for tissue).

The difference is that, at higher energies, the alphas can penetrate much more deeply. For instance, a 1 GeV alpha has a CSDA (continuous slowing down approximation) range of approximately 38 cm.
 
  • #10
fatra2 said:
Hi there,



Alpha radiation from an external source does not penetrate the first layers of the body. How can it be dangerous if it does not penetrate, even with a weighing factor of 20?

Cheers

Norman said:
I believe everyone here is assuming that by "alpha radiation" one means the alpha particle emitted during radioactive decay. The energy typical of these alphas is about 5 MeV. At 5 MeV, an alpha only travels about .004 cm in water (a proxy for tissue).

The difference is that, at higher energies, the alphas can penetrate much more deeply. For instance, a 1 GeV alpha has a CSDA (continuous slowing down approximation) range of approximately 38 cm.


Remember that the wieght factor of 20 is for damage to biological tissue. If it isn't in your body, then it doesn't even count as exposing yourself to it.
 
  • #11
Hi there,

Norman said:
I believe everyone here is assuming that by "alpha radiation" one means the alpha particle emitted during radioactive decay. The energy typical of these alphas is about 5 MeV. At 5 MeV, an alpha only travels about .004 cm in water (a proxy for tissue).

The difference is that, at higher energies, the alphas can penetrate much more deeply. For instance, a 1 GeV alpha has a CSDA (continuous slowing down approximation) range of approximately 38 cm.

1GEV! Naturally occurring decays rarely decay with that much energy, firstly. Secondly, try to imagine the penetrating power and damage done by a 1GeV photon.

Why not talk about TeV or PeV as a matter of talking. Of course, if you are expose to radiation with this type of energy, it is hard to talk about radiation protection. Their penetrating power is so great that the only was to protect against, is to run a galaxy far, far away.

Cheers
 
  • #12
fatra2 said:
Hi there,



1GEV! Naturally occurring decays rarely decay with that much energy, firstly. Secondly, try to imagine the penetrating power and damage done by a 1GeV photon.

Why not talk about TeV or PeV as a matter of talking. Of course, if you are expose to radiation with this type of energy, it is hard to talk about radiation protection. Their penetrating power is so great that the only was to protect against, is to run a galaxy far, far away.

Cheers

Photons are low LET, that is what makes them so penetrating. But that means at high energies they do not lose as much of their energy per unit track length. So a 1 GeV photon will lose less energy (lower dose) passing through a person than a 1 GeV alpha particle. So the photon penetrates farther, but dose less damage.

A 1 GeV photon still has a weighting factor of 1 compared to 20 for an alpha. So for a given dose, the alpha is much more damaging.

You wanted to know why we would even consider an Alpha having a weighting factor of 20. It can penetrate at high energies. LBNL ran a radiotherapy beam of alphas for 30 years or so. They treated over 2000 patients here. Need weighting factors for radiotherapy. Radiotherapy uses typically uses higher energies than 5 MeV for protons and heavier ions.

In addition, there is a high energy background of heavy ions permeating the solar system called galactic cosmic rays (energies from MeV to TeV are typically considered). This radiation environment interacts with the space station and the shuttles. It contributes to the total dose received by astronauts.
 

1. What is radiation and how does it affect human health?

Radiation is a form of energy that is emitted by various sources, both natural and man-made. It can be classified as ionizing or non-ionizing based on its ability to interact with matter. Ionizing radiation has enough energy to remove electrons from atoms, which can cause damage to cells and DNA. This can lead to various health effects such as cancer, genetic mutations, and radiation sickness. Non-ionizing radiation, on the other hand, has lower energy levels and is less harmful to human health.

2. What are the main sources of radiation that humans are exposed to?

The main sources of radiation that humans are exposed to include cosmic radiation from the sun and outer space, natural sources such as radioactive elements in the earth's crust, and man-made sources such as X-rays, nuclear power plants, and nuclear weapons. Some sources of radiation are more harmful than others, so it is important to understand the levels of exposure and take appropriate safety measures.

3. How does exposure to radiation affect the body?

Exposure to high levels of radiation can cause immediate health effects such as radiation sickness, which can include symptoms like nausea, vomiting, and hair loss. Long-term exposure to lower levels of radiation can increase the risk of developing cancer and other health problems. Radiation can also damage cells and DNA, leading to genetic mutations that can be passed down to future generations.

4. What are the safety guidelines for exposure to radiation?

The safety guidelines for exposure to radiation vary depending on the type and source of radiation. The International Commission on Radiological Protection (ICRP) sets guidelines for exposure limits to protect against harmful effects of radiation. These guidelines are regularly reviewed and updated based on new research and technological advancements. It is important to follow safety protocols and regulations when working with or around sources of radiation.

5. How can we protect ourselves from radiation exposure?

There are several ways to protect ourselves from radiation exposure. These include limiting our exposure time and distance from radiation sources, using protective shielding like lead aprons or barriers, and following safety procedures and regulations. It is also important to regularly monitor and assess radiation levels and take appropriate measures to reduce exposure. In the case of a nuclear accident or emergency, following evacuation and sheltering guidelines can also help protect against exposure.

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