?? What is the specific absorption rate (SAR) of a cell phone
The amount of RF energy absorbed from the phone into the user's body is known as the specific absorption rate (SAR). Different cell phones have different SAR levels. Cell phone makers are required to report the maximum SAR level of their product to the Federal Communications Commission (FCC). This information is sometimes listed inside the battery compartment on the phone. The upper limit of SAR allowed in the United States is 1.6 watts per kilogram (W/kg) of body weight.
But according to the FCC, comparing SAR values between phones may be misleading. The listed SAR value is based only on the phone operating at its highest power, not on what users would typically be exposed to with normal phone use. The actual SAR value during use varies based on a number of factors, so it's possible that a phone with a lower listed SAR value might actually expose a person to more RF energy than one with a higher listed SAR value in some cases.
?? Do cell phones cause tumors
Because cell phones are held near the head when in use, the main concern has been over whether they might cause or contribute to tumors in this area, including:
Malignant (cancerous) brain tumors such as gliomas
Non-cancerous tumors of the brain such as meningiomas
Non-cancerous tumors of the nerve connecting the brain to the ear (acoustic neuromas)
Non-cancerous tumors of the salivary glands
Researchers use 2 main types of studies to try to determine if something might cause cancer.
Lab studies usually expose animals to something like RF energy to see if it causes tumors or other health problems. It's not always clear if the results from these types of studies will apply to humans, but lab studies allow researchers to carefully control for other factors that might affect the results and to answer some basic science questions.
Another type of study looks at cancer rates in different groups of people. Such a study might compare the cancer rate in a group exposed to something like cell phone use versus the rate in a group not exposed to it, or compare it to what the expected cancer rate would be in the general population. But studies in people can sometimes be hard to interpret, because there may be other factors affecting the results that are hard to account for.
In most cases neither type of study provides enough evidence on its own to show if something causes cancer in people, so researchers usually look at both lab-based and human studies.
?? What do lab studies sugges
As noted above, the RF waves given off by cell phones don't have enough energy to damage DNA directly or to heat body tissues. Because of this, many scientists believe that cell phones aren't able to cause cancer. Most studies done in the lab have supported this theory, finding that RF waves do not cause DNA damage.
Some scientists have reported that the RF waves from cell phones produce effects in human cells (in lab dishes) that might possibly help tumors grow. However, several studies in rats and mice have looked at whether RF energy might promote the development of tumors caused by other known carcinogens (cancer-causing agents). These studies did not find evidence of tumor promotion.
A large study now being done by the US National Toxicology Program should help address some of the questions about whether exposure to RF energy could potentially lead to health issues. The study will expose a large group of lab mice and rats to RF energy for several hours a day for up to 2 years and follow the animals from birth to old age.
In the meantime, a recent small study in people has shown that cell phones may have some effects on the brain, although it's not clear if they're harmful at all. The study found that when people had an active cell phone held up to their ear for 50 minutes, brain tissues on the same side of the head as the phone used more glucose than did tissues on the other side of the brain. Glucose is a sugar that normally serves as the brain's fuel. Glucose use goes up in certain parts of the brain when it is in use, such as when we are thinking, speaking, or moving. The possible health effect, if any, from the increase in glucose use from cell phone energy is unknown.
The amount of RF energy absorbed from the phone into the user's body is known as the specific absorption rate (SAR). Different cell phones have different SAR levels. Cell phone makers are required to report the maximum SAR level of their product to the Federal Communications Commission (FCC). This information is sometimes listed inside the battery compartment on the phone. The upper limit of SAR allowed in the United States is 1.6 watts per kilogram (W/kg) of body weight.
But according to the FCC, comparing SAR values between phones may be misleading. The listed SAR value is based only on the phone operating at its highest power, not on what users would typically be exposed to with normal phone use. The actual SAR value during use varies based on a number of factors, so it's possible that a phone with a lower listed SAR value might actually expose a person to more RF energy than one with a higher listed SAR value in some cases.
?? Do cell phones cause tumors
Because cell phones are held near the head when in use, the main concern has been over whether they might cause or contribute to tumors in this area, including:
Malignant (cancerous) brain tumors such as gliomas
Non-cancerous tumors of the brain such as meningiomas
Non-cancerous tumors of the nerve connecting the brain to the ear (acoustic neuromas)
Non-cancerous tumors of the salivary glands
Researchers use 2 main types of studies to try to determine if something might cause cancer.
Lab studies usually expose animals to something like RF energy to see if it causes tumors or other health problems. It's not always clear if the results from these types of studies will apply to humans, but lab studies allow researchers to carefully control for other factors that might affect the results and to answer some basic science questions.
Another type of study looks at cancer rates in different groups of people. Such a study might compare the cancer rate in a group exposed to something like cell phone use versus the rate in a group not exposed to it, or compare it to what the expected cancer rate would be in the general population. But studies in people can sometimes be hard to interpret, because there may be other factors affecting the results that are hard to account for.
In most cases neither type of study provides enough evidence on its own to show if something causes cancer in people, so researchers usually look at both lab-based and human studies.
?? What do lab studies sugges
As noted above, the RF waves given off by cell phones don't have enough energy to damage DNA directly or to heat body tissues. Because of this, many scientists believe that cell phones aren't able to cause cancer. Most studies done in the lab have supported this theory, finding that RF waves do not cause DNA damage.
Some scientists have reported that the RF waves from cell phones produce effects in human cells (in lab dishes) that might possibly help tumors grow. However, several studies in rats and mice have looked at whether RF energy might promote the development of tumors caused by other known carcinogens (cancer-causing agents). These studies did not find evidence of tumor promotion.
A large study now being done by the US National Toxicology Program should help address some of the questions about whether exposure to RF energy could potentially lead to health issues. The study will expose a large group of lab mice and rats to RF energy for several hours a day for up to 2 years and follow the animals from birth to old age.
In the meantime, a recent small study in people has shown that cell phones may have some effects on the brain, although it's not clear if they're harmful at all. The study found that when people had an active cell phone held up to their ear for 50 minutes, brain tissues on the same side of the head as the phone used more glucose than did tissues on the other side of the brain. Glucose is a sugar that normally serves as the brain's fuel. Glucose use goes up in certain parts of the brain when it is in use, such as when we are thinking, speaking, or moving. The possible health effect, if any, from the increase in glucose use from cell phone energy is unknown.
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