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Concept of An Individualized Risk Analysis Automatically Generated by TPS Scripting

M Bach1*, G Spira2 , (1) ,Cologne, NW, (2) ,Cologne, NW,


(Sunday, 7/14/2019)  

Room: ePoster Forums

Purpose: Identification, evaluation, and prioritization of risks are the main aspects of risk management. In order to incorporate such activities into clinical radiation therapy, Huq et al proposed in AAPM’s TG 100 report a case study for intensity modulated radiation therapy (IMRT). Elements of this workflow can be analyzed by scripting the facility’s treatment planning systems to automatically generate patient specific risk values.

Methods: The process map from TG 100 was adopted to local conditions and a subset of risk related aspects was chosen for automated evaluation during the planning process. Numerical values to the parameters occurrence (O), severity (S) and lack of detectability (D) were assigned and according to failure modes and effects analysis (FMEA), an individual risk priority number (RPN=O·S·D) can be calculated by TPS scripting (in our case ARIA/Eclipse v.15.6). This value represents a relative surrogate metric for the risk posed to the patient.

Results: Depending on the patient’s intended treatment and demographics, the script triggers the planning system to calculate or extract various parameters and compares these against reference values. Thus, the calculated volume histograms can be checked against dose prescriptions and target structures on consistency. Improvements resulting from these actions are lower patient specific risk priority numbers by reducing the occurrence of the cause (e.g. by re-visiting the contouring workflow step) and improving the detection of the failure mode (e.g. by performing an independent dose calculation with a second algorithm).

Conclusion: This concept of an individualized risk analysis automatically performed by TPS scripting gives added value/information, is easy to use, and can be extended (especially in combination with additional data from the oncology information system). Before clinical routine, the risk contributor’s occurrence, severity and lack of detectability should be thoughtfully evaluated and further discussions with other institutions and organizations triggered.


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