The only way to tell if your home has an unacceptable level is to test it. If the level is too high, then fans may help. Some new homes are being built with the infrastructure to vent Radon by adding a fan already in place. If this is not true for your home and a fan is needed, it may cost up to a couple of thousand dollars to retrofit the home to vent Radon gas. Yes, the fan can draw Radon away from the house and vent it to the atmosphere.
Radon enters the home through cracks and openings in the foundation.
If the levels are only slightly elevated, simple measures such as caulking and fixing cracks may have the desired effect. Higher levels need more sophisticated remediation measures. This may include ventilating the soil underneath the home's foundation and venting the Radon gas to the atmosphere. This should be done by professionals since if the pressures are not correctly balanced, there is a possibility that fans could actually increase the amount of Radon in the home. Epidemiologic studies try very hard to separate out the causes for the lung cancer.