Introduction: Clinical processes are meant to restore the patient's health but often show weaknesses regarding their efficiency (e.g. ineffective task distribution for clinicians, long waiting times for patients). In order to improve these processes an assessment of their quality is needed. This assessment is based on adequate process models and proper systematic assessment procedures. Both seem not sufficiently present in the Activity Diagrams of the Unified Modeling Language (UML) or ARIS Event-driven Process Chains (EPC). Objectives: The aim of this paper is to develop and test a process modelling method which explicitly includes all details of clinical processes necessary for a systematic and even semiautomatic quality assessment. Methods: We propose a model which is separated into process model, tool model, organisation model and information model. Its visualisation is based on the extended UML Activity Diagrams.Results: After being defined formally the graphical elements of the proposed model were implemented into a commonly used modelling software. As a first validation step, various versions of the process of ordering a radiological examination were modelled. Discussion: The advantage of our modelling approach is the combination of different aspects (i.e. description of processes, used tools, information objects and actor roles) into an integrated model so that details important for a systematic process assessment are now more explicitly included than in Activity Diagrams or EPC. Further evaluations will help to improve the model and to develop strategies for the semi-automatic analysis.