Current methods used in Gene Therapy include the introduction of a virus into the body so that it can fight off the virus causing the problem. This method, however can prove dangerous and isn't always effective.
A new method, developed in a joint operation between the Imperial College London and the UK Medical Research Council, uses both microbubbles and ultrasound and has been successfully tested on mice.
When the microbubbles (tiny bubbles of gas) are used in combination with Ultrasound, it causes the bubbles to pop and allows the new DNA into the infected system. This method brings hope to those suffering from diseases such as muscular dystrophy. http://news.bbc.co.uk/2/hi/health/2780325.stm