The study presents cases of accidents that occurred during radiation therapy and discusses associated publicly available post-market surveillance data. Based on this data it recommends how to use post-market surveillance data from adverse event and recall databases for risk management. The ISO 14971 and IEC 62304 standards as well as FDA guidance documents require medical device manufacturers to periodically analyze post-market information about their own and similar devices following their production and software delivery. This post-market information is reviewed as part of the post-production requirement as stated in ISO 14971. Major sources of post-market surveillance data are adverse event and recall databases maintained by several competent authorities. However, a guideline on how to capture and use this data is missing in the existing literature because the database content and structures are not harmonized. This study is based on the databases of the Competent Authorities in the U.S. (FDA) and Germany (BfArM), and compares the valid reporting regulations for medical device users and manufacturers. Focus of this study is on risks enabled by inadequate software in radiation therapy systems.