Treatment Ontology Framework of Clinical Practice Guidelines Eman Alqaissi and Samir El-Masri College of Computer and Information Sciences King Saud University, Riyadh, Saudi Arabia eman.alqaissi@gmail.com selmasri@gmail.com Abstract The goal of computerizing Clinical Practice Guidelines (CPGs) is to facilitate their use in practice. Many models are presented and used in different Decision Support Systems (DSSs). These models concern about representing CPGs in different ways, but none of them is used as a framework that unifies CPGs development. The problem exists when medical experts whose job focuses on the development of CPGs, try to develop them by using different templates. This paper proposes such an ontology framework; that is especially in treatment recommendations. The framework unifies the representation of CPGs in a machine-readable format by adopting the use of SNOMED CT terminology for all instances. In addition, it meets the reusable, comprehensive, efficiency, flexibility, accuracy, and consistency benefits. Key words: clinical practice guidelines, activity diagram, class diagram, SNOMED CT, ontology, knowledge base, framework, treatment 1. Introduction A Clinical Practice Guideline (CPG) has been defined by the Institute of Medicine (IOM) as "systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific circumstances." [1]. The benefits of CPGs are numerous, they can be used to improve the process and outcomes of health care, to make efficient use of resources, and to improve the quality of clinical decisions; which will improve the patient care quality, reduce medication errors, and minimize the cost of patient treatment. CPGs allow the use of knowledge at the appropriate point of patient care, and also the reuse of knowledge when it is applied to different situations [2]. CPGs are prepared by panels of expertise and they are evidence-based. Many countries concerned about the development and implementation of CPGs such as Australia, Canada, England, United State and Japan [3]. The ontology concept is used for representing CPGs, in literature; many definitions for ontology were introduced. Gruber [4] proposed the most popular definition of ontology as "…a formal, explicit specification of shared conceptualization". SNOMED CT is the most comprehensive reference clinical terminology constantly updated, to support the effective coding, retrieving, and analyzing of clinical data, with the aim of improving patient care. SNOMED CT is used in over 50 countries around the world and is a key terminology standard recommended by Infoway for use in health information and communication technologies in Canada [5]. In addition, the American academy of ophthalmology adopts the use of SNOMED CT [6].