ESTRO 2022 - Abstract Book

S1342

Abstract book

ESTRO 2022

Results A software termed IS 2 aR ( Interactive Software for Image Segmentation and Registration ) was created. It allows for registration of the patient’s PCT with the ICRP110 phantom. Figure 1 presents a screenshot of the program graphical interface. The results in a chest IV are shown in figure 2.

Figure 1 shows the interface for a pelvis case: patient's CT and ICRP110 (left column), their respective bone segmentations (center column), and the synthetic whole-body CT obtained by registering the subregions, together with their Sørensen- Dice index and transformation matrix (right column).

Figure 2 shows the validation in a coronal and sagittal view of the program, with the overlay of the whole-body CT (yellow) and the synthetic whole-body CT (red) generated by abdomen registration. Conclusion A user-friendly computational tool to generate synthetic patient-specific whole-body CTs was developed. It may be used, for example, for the accurate determination of peripheral dose during radiotherapy using our Periphocal 3D software (see abstract E22-0473). This is an important step towards personalized treatment planning that takes into consideration the probability of second cancer induction.

Acknowledgements:

Fondecyt N1181133 The Free Access Decedent Database funded by the National Institute of Justice grant number 2016-DN-BX-0144 .

PO-1560 An investigation of gamma parameters for VMAT plans treating multiple metastases

L.S. Fog 1 , F. Gagliardi 2

1 The Alfred Hospital, Radiation oncology, Melbourne, Australia; 2 The Alfred Hospital, Radiation Oncology, Melbourne, Australia Purpose or Objective The simultaneous irradiation of multiple metastases represent a particular challenge since the radiation fields may be large but the positional resolution required is high. In this work, we investigate patient-specific quality assurance measurements (PSQAMs ) for such plans with several different measurement systems, and investigate pass rates and failure modes for several different criteria. Materials and Methods Ten patients treated with volumetric modulated arc therapy (VMAT) for multiple metastases (MMs) or hippocampus sparing whole brain radiotherapy (HSWBRT) with VMAT at our clinic were included. Each plan was calculated using Eclipse™ (Varian, Palo Alto), Acuros v 13.6 with a calculation grid size of 1.25 mm. PSQAM were carried out using Octavius/ Verisoft v 7. (O/V, PTW) and Portal Dosimetry (PD, Varian). Additionally, for one particularly complex case, film measurements were