ESTRO 2023 - Abstract Book

S1571

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ESTRO 2023

Results 9. Ambient light of the treatment room: an accuracy lower than 0.3 mm is observed in figure 1 for both cases. A p value of 0.02, 0.018 and 0.3 for vertical, longitudinal and lateral axis respectively was obtained.

• System state: It is observed, in figure 2, that state B (reference) has an accuracy lower than 0.3 mm, better than the other two states (higher than 0.5 mm in vertical and longitudinal axis). P-values lowers than 0.05 were obtained for all axis. • Gain of cameras: For every axis, a p-value over 0.05 was obtained (0.54, 0.71 and 0.45 for lateral, longitudinal and vertical axis respectively). Similar accuracy in all axis was observed (figure 2).

Conclusion It has been observed that the gain can be modified without affecting the positioning under the measure conditions evaluated. In the other two cases, it is noted that there are significant differences when the measurement conditions are changed. Therefore, ED must be operated in warm-up state B and without ambient light, due to their influence to the position achieved by the SGRT system.

PO-1837 Predictive factors of survival and relapse in SBRT of liver metastases

C. De La Pinta 1 , J.D. García 2 , D. Sevillano 3 , A. López 4 , J. Nuño 5 , R. Peromingo 5 , M.R. Ferreiro 6 , R. Fuentes 7 , C. Guillén 7 , I. Martínez 7 , P. Reguera 7 , M. Rodriguez 7 , J. Cobos 8 , A. Olavarria 8 , A. Palomera 8 , R. Romera 8 , J.A. Rojo 9 , A. De Cozar 9 , L.C. Perna 10 , A. Albillos 11 , S. Sancho 9 1 Ramon y Cajal Hospital IRYCIS, Radiation Oncology, Madrid, Spain; 2 Ramón y Cajal Hospital, Medical Physics, Madrid, Spain; 3 Ramon y Cajal Hospital, Medical Physics, Madrid, Spain; 4 Ramón y Cajal Hospital, General Surgery, Madrid, Spain; 5 Ramon y Cajal Hospital, General Surgery, Madrid, Spain; 6 Ramon y Cajal Hospital, Medical Oncology, Madrid, Spain; 7 Ramón y Cajal Hospital, Medical Oncology, Madrid, Spain; 8 Ramón y Cajal Hospital, Radiology, Madrid, Spain; 9 Ramón y Cajal Hospital, Radiation Oncology, Madrid, Spain; 10 Ramón y Cajal Hospital, Pathology, Madrid, Spain; 11 Ramón y Cajal Hospital, Gastroenterology, Madrid, Spain

Purpose or Objective