Baiyun International Airport in South China's Guangzhou has strengthened its border control by installing nuclear radiation detection devices, Nanfang Daily reports.

Since the installation two months ago the detection tool has identified two sources of nuclear radiation, a female American Chinese and a male foreigner. Both were cancer patients with radionuclide implanted inside their bodies during surgery as an anti-cancer agent.

The two passengers were green lighted to enter Guangzhou since their radioactive elements posed no threat to public security.

The detection device is said to be able to check radionuclide energy forms such as gamma rays and neutrons, which exist on objects and human bodies.