ESTRO 2022 - Abstract Book

S406

Abstract book

ESTRO 2022

Results Table 1 displays the best CV HCIs and their corresponding testing HCIs of different models. Compared with previously published works, there were improvements in CV and testing HCIs for both DM and OS. Generally, PET achieved better predictive performance than CT in both CV and testing cohorts. Besides, PET-only outperformed PET with GTV contour (PET-GTV), indicating that GTV segmentation might not be indispensable in PET-based prognosis. Comparatively, GTV contours could be important for CT-based prognosis, since the CT-only testing HCIs were poor. Although higher than the CT-only model, the HCIs of joint PET/CT were not improved compared to the PET-only model. This could be explained by the redundancy over different imaging modalities and might also suggest that multi-channel input is not optimal to exploit multi-modality information. Fig. 1 shows the Kaplan-Meier curves of the PET-only and CT-GTV models (the best choice for each modality), demonstrating the significant stratification capability of the trained models for the testing cohort.

Conclusion DL-based DM and OS time-to-event models showed predictive capability and could benefit personalized RT treatment. The high accuracy of the PET-only model also suggested GTV segmentation might be less relevant for PET-based prognosis. The predictive performance of joint PET/CT could not be directly improved from the PET-only model and remains to be explored in future studies.

Proffered Papers: AI & advanced practice

OC-0461 IGRT practice in the Netherlands: Does the current RTT curriculum need to be adapted?

K. van Engen 1,2 , M. Kamphuis 2 , M. Soumokil-de Bree 2 , L. van Zadelhoff 2

1 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands; 2 Inholland University of Applied Sciences, Faculty of Health, Sports and Social work, Haarlem, The Netherlands Purpose or Objective Image Guided (Adaptive) Radiation Therapy (IG(A)RT) is constantly evolving. For educational institutes it is a continuous process to adapt their curriculum to the actual clinical practice. It is unclear whether the current IGRT curriculum is in line with the actual clinical practice in RT departments in the Netherlands. The aim of this study is to evaluate whether the curriculum suits the current and prospective professional practice in IG(A)RT in the Netherlands. Materials and Methods A survey was performed to evaluate current clinical practice with regard to IG(A)RT. This was sent to all 21 main locations of RT departments in the Netherlands. Several target areas were included in the survey (Figure 1). Questions covered the use of following IGRT techniques: • In-room imaging; 2D kV /2D MV (Portal) Imaging or 3D /4D Cone Beam CT (CBCT). • Image guidance protocols; online (translation/rotation(6D)/Library Of Plans (LOP)/adaptive), offline ((e)NAL/SAL).