ESTRO 2022 - Abstract Book

S1465

Abstract book

ESTRO 2022

Materials and Methods The process for the bolus production is the following. First, the bolus design is made in Monaco (v.5.51) based on the anatomy of the patient. After that, the file structure created is exported and converted to a .stl file with 3DSlicer (v.4.11). Before it is ready to print, smoothing is needed (Meshmixer, v.3.5). Finally, the file is sent to Ultimaker Cura (v.4.6.1) printer and printed with PLA filament. As this bolus is personalized, it is used by only one patient during all the treatment following medical considerations. A multidisciplinary working group composed of a Radiation Oncologist, Medical Physicists, 3D-printing experts, and the person in charge of regulatory in medical devices from our institution analyzed the risks associated with every stage of the bolus production and its application according to ISO 14971:2019 “Medical devices - Application of risk management to medical devices”. Actions required to minimize the risks were also elaborated. A risk-impact matrix was used to identify potential risks. It provides the impact of the medical devices on patient safety (the probability of occurrence of harm and the consequences of that harm). The multiplication of these two factors gives us a risk priority index (RPI) to establish preventive, corrective, or improvement actions before its use in patients (Table 1).

Results The working group identified 4 stages (Design, Production/Printing, Storage, and Application) and 16 risks in the 3D printing process of radiation therapy boluses, which were analyzed and evaluated (Table 2). The risks were distributed as follows: 3 in the design process, 8 in 3D printing, 1 in storage, and 4 in the application. The critical risks were considered with PRI>5 and special attention was paid to elaborate actions to minimize them. For example, an image registration between the virtual bolus and a CT of the printed bolus is proposed for the risk “Printing another bolus file, not the requested”.