It is believed an outbreak of TB in north London in January 2000 caused about 184 infections, Sir Liam revealed. "We need to utilise new technology such as mobile x-ray machines and genetically fingerprinting the disease to cut the number of infections," he said. The x-ray machines, which will cost about ?400,000 each, will be used to monitor high-risk patients such as recent arrivals from abroad, prisoners and the homeless.