Introduktion: De nødvendige informationer til visitation afCT-skanning er lokaliseret i heterogene patientadministrative,kliniske, og parakliniske informationssystemer. Studietsformål er at understøtte visitationen ved at genanvende relevantedata på tværs af disse informationssystemer. Detteudføres ved mapping til referenceterminologien SNOMEDCT.Metode: Visitatorernes informationbehov blev afdækketgennem observationer og fremgangsmåder til mapping blevafdækket vha. systematisk litteratursøgning. Observationerneblev analyseret ved brug af tematisk analyse, og for hvertrelevant tema, blev der identificeret kildebegreber, der kunneudtrykke dette. Mapping af kildebegreberne til SNOMEDCT blev udført i en iterativ proces, hvor der blev udviklet enguideline til konsekvent udførelse af mapping. Afslutningsvisblev en brugergrænseflade udviklet mhp. at evaluere degenanvendte datas understøttelse af visitationen.Resultater: Gennem observationerne blev ni temaer identificeret,som resulterede i 93 kildebegreber. Der blev udvikleten guideline for mapping til SNOMED CT gennem tre iterationer.98% af kildebegreberne kunne mappes til SNOMEDCT, hvoraf 77% blev mappet som et præcist match. Evalueringenviste, at de genanvendte data understøttede visitationentil CT-skanning.Konklusion: SNOMED CT er et fleksibelt værktøj, der kananvendes til at mappe kildebegreber fra alsidige begrebssamlingerog dermed at genanvende data på tværs af patientadministrative,kliniske, og parakliniske informationssystemer.Introduction: The information necessary to process a CT referralis located in heterogeneous administrative, clinical andparaclinical information systems. The purpose of this studyis to underpin the processing of referrals by reusing relevantdata across information systems. This is performed throughuse of the reference terminology SNOMED CT.Methods: The informational needs, when processing a CTreferral, were investigated through observations and mappingmethods were identified using a systematic literaturesearch. The observations were analyzed using thematic analysis,and for each relevant theme, source terms were identifiedto express these. Mapping of the source terms to SNOMEDCT was performed through an iterative process wherea guideline was developed, to ensure consistent execution ofthe mapping. Finally, a user interface was developed to evaluate,whether the reused data, was able to underpin processingof referrals.Analysis: Through analysis of the observations, nine themeswere identified, which resulted in 93 source terms. A guidelinefor mapping to SNOMED CT was developed throughthree iterations. 98% of the source terms could be mappedto SNOMED CT, of which 77% were mapped as an exactmatch. The evaluation showed that the reused data, was ableto underpin processing of referrals.Conclusion: SNOMED CT is a flexible tool which can beused to map source terms from versatile collections of termsand can therefore be applied to reuse data across administrative,clinical and paraclinical information systems.