| IRTIS | Integrated Radiation Therapy Information System |
|---|---|
| IS | ileal segment; immediate sensitivity; immune serum; immunosuppression; impingement syndrome; incenti... |
| ISD | immunosuppressive drug; Information Services Division; inhibited sexual desire; interstimulus distan... |
| ISI | infarct size index; initial slope index; injury severity index; Institute for Scientific Information... |
| ISM | information sources map [of UMLS]; International Society of Microbiologists; intersegmental muscle |