But the pair of studies by the US National Toxicology Program found “clear evidence” that exposure to radiation caused heart tumors in male rats, and found “some evidence” that it caused tumors in the brains of male rats. (Both are positive results; the NTP uses the labels “clear evidence,” “some evidence,” “equivocal evidence” and “no evidence” when making conclusions.)
If you want to use your phone for talking, then the idea is that you keep it flipped over the front of the screen – that way you’re blocking radiation on both the front and back. The speaker still works with the cover on, because there’s a small hole for that. The inevitable drawback of this is that you have to flip the cover open in order to access your keypad.

The FCC provides information about the specific absorption rate (SAR) of cell phones produced and marketed within the last 1 to 2 years. The SAR corresponds with the relative amount of radiofrequency radiation absorbed by the head of a cell phone user (47). Consumers can access this information using the phone’s FCC ID number, which is usually located on the case of the phone, and the FCC’s ID search form.
It isn’t just cell phones. When you get the phantom twitch, it is not from a nervous system reaction to the phone vibrator as many suggest. Why do I say that? One, I rarely experience phone vibration, yet I get the phantom twitch. Two, as I have to use a rental car for work and they always give you two electronic keys (they do NOT vibrate), that is in my pocket with my own car key, bringing the total of non-vibrating keys to three. They do not vibrate, but I still get the phantom twitch.
Instead of more animal and even epidemiological studies, he thinks researchers should focus on finding the mechanisms by which cellphone radiation may affect human health. Since we’ll never have an RCT on cellphones and cancer, he added, studies should measure actual cellphone use and exposure to radio-frequency radiation, instead of estimations of how much people are exposed (which most studies currently do).
First, you must have a proper meter. To check for magnetic field emissions, an AC Gaussmeter will work. Most AC gaussmeters will have an internal probe. Simply position the gaussmeter on the phone. Note carefully where the meter is positioned. Make a call and watch the readings. Notice the highest and lowest readings, and make a mental note of the "average" reading. Now, insert the magnetic shield, and repeat.
As a result, stories about a single nuclear meltdown or possible link between cellphone radiation and cancer will be amplified much more than news about the nine people who probably died today in the US from distracted driving. “This possible health effect from radiation is pretty esoteric at this point. If there is anything there, it seems to me like it’s going to be very, very small,” says Kenneth R. Foster, a bioengineering professor at the University of Pennsylvania who has been investigating whether there are biological effects from radio waves since the 1970s. “Driving and texting, people get killed doing that — but it’s not a very exciting risk to worry about.”
Several nations have advised moderate use of mobile phones for children.[45] A journal by Gandhi et al. in 2006 states that children receive higher levels of Specific Absorption Rate (SAR). When 5- and 10-year olds are compared to adults, they receive about 153% higher SAR levels. Also, with the permittivity of the brain decreasing as one gets older and the higher relative volume of the exposed growing brain in children, radiation penetrates far beyond the mid-brain.[46]
Still think Pong’s SAR testing prove you are safer? Take this for example, the Samsung Galaxy Note 5 SM-920V FCC ID A3LSMN920V (Official FCC Doc) made for Verizon has an FCC measured SAR of only 0.21 W/kg (watts per kilogram) and the Apple iPhone 6 Plus exposes a user’s head to a whopping 1.18 W/kg FCC ID: BCG – E2817 Apple iPhone 6 SAR  (Official Doc Page 138).  That’s a dramatic difference of several hundred percent from highest SAR to lowest SAR on these high-end smartphone devices.

The U.S. government doesn’t seem very troubled, either. The Food and Drug Administration says on its website that research generally doesn’t link cell phones to any health problem. And although the Federal Communications Commission requires manufacturers to include information in user manuals about cell-phone handling, that’s often buried deep in the fine print.

The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.