CyberKnife is non-invasive, painless radiosurgery for treating cancer. Even cancers that are difficult to treat with conventional surgery can be removed without damaging surrounding tissue by applying low-dose X-rays at different angles. One treatment takes just 30 minutes and doesn't require a hospital stay. The technology originated in the US and was improved by a Japanese doctor. The number of patients he has treated with it is among the highest in the world.