ESTRO 2023 - Abstract Book

S1518

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ESTRO 2023

After applying a Student’s t-test we can confirm with a 95% confidence interval that there are significant differences between the results obtained with OD1600SRS and OD1500 (in favour of the first one), even using double measurement to improve spatial resolution of OD1500:

• OD1600SRS vs OD1500HR: p-value = 4.44 · 10^(-6) • OD1600SRS vs OD1500: p-value = 1.57 · 10^(-8) Table 2: OD1600SRS vs OD1000SRS

Nevertheless, no significant differences can be found between OD1600SRS and OD1000SRS:

• OD1600SRS vs OD1000SRS: p-value = 0.42

Conclusion Differences in gamma results up to 7.3% has been found between OD1500 and OD1600SRS, in favour of OD1600SRS, but we see no significant deviations between the results obtained with OD1600SRS and OD1000SRS in small VMAT volumes.

On the other hand, OD1600SRS achieves significant better results than OD1500 even with double resolution (OD1500 HR)

We conclude that, for patient QA procedure in relatively large and smaller target volumes, OD1600SRS yields the best results regardless of the volumes to be measured.

PO-1795 Energy-dependence of the Exradin W1 scintillator for low and medium-energy x-ray beams

P. Carrasco de Fez 1 , N. Jornet Sala 1 , P. Gallego Franco 1 , J. Pérez-Alija Fernández 1 , C. Ansón Marcos 1 , N. García Apellaniz 1 , N. Tejedor Aguilar 1 , M. Barceló Pagès 1 , H. Vivancos Bargalló 2 , F.M. Leo Martínez 1 , A. Domínguez Perea 1 , A. Ruiz Martínez 1 1 Hospital de la Santa Creu i Sant Pau, Servei de Radiofísica i Radioprotecció, Barcelona, Spain; 2 Hospital de la Santa Creu i Sant Pau, Servei de Radiofísica i Radioprotecció, BArcelona, Spain Purpose or Objective 4. To study the energy dependence of the Exradin W1 scintillator for x-ray beams from a surface therapy treatment unit. 5. To clarify the origin of the dependence.