S2955
RTT- RTT operational practice and workflow innovations
ESTRO 2026
Department of Oncology, Copenhagen University Hospital – Herlev and Gentofte, Copenhagen, Denmark
investigate the success rate of the Xsight Lung Tracking method when tumors are < 15 mm and to determine the local control of these small tumors after treatment with Xsight Lung. Material/Methods: In this retrospective study, patients who were treated with the Xsight Lung Tracking method on the CyberKnife system were screened for inclusion between December 2019 and December 2023. The inclusion criteria for this study were: 1) a Lung Optimized Treatment simulation was performed to determine if the CyberKnife system can track the tumor with Xsight Lung, 2) the largest diameter of the gross target volume (GTV) in the axial CT slice was smaller than 15 millimeters on the planning CT in mediastinal window. The medical-ethics committee of Erasmus Medical Center approved this study (MEC- 2023-0357). Results: Of the 465 patients who were screened, 93 patients met the inclusion criteria. Of these 93 patients, only 16 tumors were visible during the Lung Optimized Treatment simulation and were treated with the Xsight Lung Tracking method (17% success rate). The number of 1- and 2-views were 14 (88%) and 2 (12%) respectively. 13 patients had a primary lung tumor and 3 patients had metastases. All patients were irradiated with one of the following schedules: 3x17Gy and 5x11Gy. The median size of the tumors was 12 mm.The actuarial local control of these 16 tumors at 3 years was 94%. One patient experienced a local recurrence after 9 months. The overall survival at 42 months was 46%. The mean overall survival time was 29.0 months. The median follow up of the whole group was 19 months. Conclusion: An excellent actuarial local control of 94% at 3 years was found for tumors <15 mm who were treated with the Xsight Lung Tracking method on the Cyberknife system. However, the success rate of tracking tumors <15mm using the Sight Lung Tracking method is limited to 17%. Keywords: Lung Cancer, Stereotactic, Tumor tracking
Purpose/Objective: Purpose/objective: The standard palliative
radiotherapy (RT) workflow involves long waiting times or multiple clinic visits, which can be burdensome for patients suffering from painful bone metastases. Simulation-free radiotherapy utilizes a recent diagnostic CT (dCT) for target delineation and treatment planning, thereby eliminating the need for a separate planning CT. When combined with CBCT- guided online adaptive radiotherapy (oART), which allows for real-time adjustments to the treatment plan, this approach offers the potential for a more efficient workflow for patients receiving palliative RT.This studyreports the initial experience of implementing a simulation- freeoART workflow and evaluatesitsimpact on treatme nt time and patient experience. Material/Methods: Materials/methods: Patients referred for single- fraction treatment of painful spinal and non-spinal bone metastases were eligible for inclusion, provided they had an available dCT.The dCTwasused for targetdelineation a nd treatmentplanning. The overall treatment time (patiententering and leaving thetreatment room) for simulation-free oART was measured and compared with that of standard IGRT treatments. Additionally, the simulation-free treatments were timed at each of the following step: 1) patient entering the room, 2) CBCT acquisition, 3) contour editing finish, 4) optimization time finish, 5) plan review, 6) start of treatment, 7) end of treatment, and 8) patient leaving the room. An in- house developedquestionnairewasused to assess pati ent satisfaction. Results: Results: 41patients with spinal metastases and four patients with non-spinal metastases were treated using the simulation-freeoART workflow. The median [IQR] overall treatment time for the simulation- free oART treatments was 29.4 minutes [IQR = 26.2; 36.1] compared to an overall treatment time of 23.0 minutes [18.0; 27.0] for 44 IGRT treatments (Figure 1). Figure 2 shows the time consumption for each step in simulation-free adaptive treatments for each patient. Despite the longer treatment times, patients reported high satisfaction, with 100% of the patients indicating they would prefer a simulation-free oART workflow if referred for
Digital Poster 5163
Initial experience of implementing a simulation- free online adaptive radiotherapy workflow for patients receiving palliative radiotherapy Lisette Juul Sten, Anna Mann Nielsen, Laura Ann Rechner, Gitte Fredberg Persson
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