ESTRO 2024 - Abstract Book

S3966

Physics - Image acquisition and processing

ESTRO 2024

Keywords: CBCT, Gamma Knife, Deep learning

3116

Digital Poster

A Multi-disciplinary engagement to generate guidelines for PET-CT in radiotherapy treatment planning

Susannah Jansen van Rensburg

GenesisCare, Maidstone, Kent, United Kingdom

Purpose/Objective:

PET-CT (Positron-Emission Tomography-Computed Tomography) is being used increasingly in radiotherapy planning, especially in the treatment of metastatic disease where PET-CT modalities are sensitive to demonstrating metabolically active lesions, and hence may be particularly important in Stereotactic Ablative Radiotherapy (SABR) (Hardcastle et al, 2023). The use of PET-CT in radiotherapy is truly multi-disciplinary due to the use of functional imaging alongside morphological planning CT data. To date, there are limited recommendations for how to appropriately use PET-CT during the planning process, to make the most of the modality authentically and in support of target volume delineation for radiotherapy (Pike et al, 2019). The purpose of this work is to identify some recommendations for best practice that may be used for the safe inclusion of previously completed PET-CT in radiotherapy planning, from the perspective of the radiotherapy treatment planning team.

Material/Methods:

This work was qualitative in nature, involving interview of multiple disciplines of professionals to discuss requirements and recommendations for the use of PET-CT in radiotherapy treatment planning:

• A single consultant radiologist in nuclear medicine: discussed factors involved in PET-CT acquisition and post-processing, dataset creation, and how these images are interpreted and reported by the radiologist. Emphasis was placed on elements such as the use of different uptake thresholds according to tracer or diagnosis, or the ability to switch between them depending on interpretation requirements. • 5 clinical oncologists : this group focused on selecting the most clinically relevant dataset (where multiple existed) in terms of the radiotherapy delivery. Opinions were collected as to the optimal way to view PET-CT data in the radiotherapy software to facilitate their contouring, and they placed priority on ensuring image fusion is localised to the relevant treatment area. • 5 radiotherapy physicists: input here focussed on how PET-CT imaging data could be fused with the radiotherapy planning data without compromising the quality of authenticity of either dataset. Different planning systems and image fusion suites were trialled to assess the impact of the display.