ESTRO 2020 Abstract book

S1136 ESTRO 2020

1 USL Toscana Centro, Radiotherapy, Prato, Italy ; 2 A.O.U. Careggi, Radiotherapy, Florence, Italy Purpose or Objective FMECA (Failure Modes, Effects and Criticality Analysis) is a prevention tool with a proactive approach that allows for the identification and subsequent prevention of diverse process risk phases. This study reports the results obtained from FMECA analysis applied to VMAT (Volumetric Modulated Arc Therapy) of patients undergoing radiotherapy treatments at Santo Stefano Hospital in Prato, Italy. Material and Methods A multidisciplinary team was composed of 8 health care professionals; the team leader was the Department Manager. VMAT prostate treatments was divided into 7 steps: Step 1: Admission and medical examination, Step 2: Programming, Step 3: Simulation CT scan, Step 4: RT Treatment and Planning, Step 5: First RT treatment session, Step 6: Daily RT session, and the final step (No. 7): final RT session. Each phase was divided into several processes for a total of 109 steps. For each step, the following factors were rated, using a scale of parameters ranging from 1 to 10, and each of the individual parameters was discussed by the group: occurrence, severity, detectability. The sum of these three values represents the Risk Priority Number (RPN) parameter. Three different types of processes have been distinguished, based on the RPN values: • RPN <61: Low risk process • 61 91: High-risk process For all high-risk processes, a corrective action had been proposed, while for moderate-risk processes, careful and meticulous monitoring strategy was chosen. No interventions were performed for low-risk processes except that of monitorization. The workflow of the entire RT process was monitored using the quality checklists present in the system Record&Verify (MOSAIQ version 2.64.278, Elekta healthcare). Results 96 low-risk processes (RPN <61), 9 moderate-risk processes (61 91) were detected. (Figure 1) The box diagram summarizes the process trend for each phase in terms of RPN values reported in Figure 2. The process with the highest RPN (125) refers to Step 1 (admission and medical examination). Simulation CT seems to be the RT step in which different processes have high RPN value (2 moderate risk and 2 high risk processes).

(Figure 2)

Conclusion 60 percent of moderate and high-risk processes were related to correct patient preparation upon the patient’s arrival for Radiotherapy (Example: empty bowel and full bladder), that are difficult to standardize for all patients. At the end of FMECA, analytical actions to improve the method were evaluated and implemented for the 4 processes with RPN > 91. To evaluate the effects of these actions further FMECA study is in the planning phase. The corrective actions noted in the study will be evaluated at 6 month and 12 month intervals. PO-1945 Practical test of proton plan before first treatment P.O. Haslund 1 , U. Ingerslev 1 , M. Giortz 1 , S. Frost 1 1 Aarhus University Hospital, Danish Center for particle therapy, Aarhus, Denmark Purpose or Objective The workflow when treating with protons differs from conventional radiotherapy. The reasons are mainly that the gantry and the couch are two separate units and the risk of collision is present. Furthermore the proton gantry has a snout, which I moving very close to the patient during treatment. It's not possible to test the risk of collision when preparing the treatment plan. A practical test at the gantry is necessary with the following aims: To maintain patient safety To minimize the time at the patients first treatment Quality assurance of the treatment instructions in the clinic To let the RTT's practice the specific workflow To obtain practical experiences to the treatment planners Material and Methods A systematic test of the workflow was conducted on 10 treatment plans before the first treatment to identify technical and practical issues. In the clinic the test was called 'Dry run'. The following were tested: Are the planned gantry angles possible? Planning of the optimal field order? Test the risk of collision between the gantry and the couch? Test the risk of collision with the patient? Planning of the optimal angle to begin the CBCT scan? Planning of the optimal angles for kV images? Test if it's possible to deliver all spots during treatment? When the treatment plan was tested in the dry run the evaluation was documented in a worksheet. Results By conducting the dry runs we decided the optimal field order and directions to move the gantry. Furthermore we identified if the treatment plan wasn't possible to deliver because of collision.

(Figure 1)