In this paper, I propose a data-based query expansion technique to support scenario specific retrieval in the medical domain. A data-based query expansion technique takes advantage of the UMLS (Unified Medical Language System) data source to append the original query with additional terms that are specifically relevant to the query’s scenario, thus improving upon traditional query expansion approaches. I compare this technique with cross-search method that only refer to the encyclopedia and expand terms that are not necessarily scenario specific. The study on the clinical notes shows that the data based techniques that results in scenario-based expansion outperformed over the cross-search and automatic query expansion method on average in all categories of scenarios.