55th SSRMP Annual Meeting

Session

Session II: Radiobiology, Radiomics, Adaptive RT

27 Oct 2022, 13:45

Lachensaal & Foyer (Kultur- und Kongresszentrum Thun)

35. Dose guidance in daily adaptive proton therapy: Predicting the cumulative treatment dose

Evangelia Choulilitsa (PSI - Paul Scherrer Institut)

27/10/2022, 13:45

Radiation Therapy

Oral

Purpose: The prescribed treatment dose, routinely calculated on the planning CT and approved by the radio-oncologist, is assumed as the dose applied for the whole treatment (ApprovedTD). However, in online daily adaptive proton therapy (DAPT), the plan is optimized on the daily CT to correct for anatomical daily changes, while the patient is lying on the treatment table. Intrinsically, both...

17. Dosimetric accuracy verification of treatment plans generated during online adaptive radiotherapy

Daniel Schmidhalter (Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.)

27/10/2022, 13:55

Radiation Therapy

Oral

Purpose

When performing online adaptive radiation therapy (ART), dosimetric measurements of the treatment plan of the day with the aid of a phantom before applying the dose to the patient is not possible. Typically, a dose recalculation with an independent system is done in this situation. In order to verify the accuracy of the dose distributions delivered by these online ART plans, for a...

11. MET-targeting CAR T cells enhance tumor cell killing and cytokines release in glioma models when combined with radiation therapy

Lusine Hovhannisyan (University of Bern, University Hospital Bern)

27/10/2022, 14:05

Radiobiology

Oral

Glioblastoma (GBM) is the most frequent primary brain tumor with dismal prognosis after radiation therapy, a standard treatment option for this disease. Recently, RT has been investigated as a mediator of effects of T cell-based therapies in the context of immunosuppressive GBM microenvironment. The MET receptor is an oncogene involved in radiation resistance, and stem-like properties of GBM....

10. Fractionated radiation therapy increases Siglec-7 and -9 ligands expression in cancer cells

Lusine Hovhannisyan (University of Bern, University Hospital Bern)

27/10/2022, 14:15

Radiobiology

Oral

Purpose: Radiation therapy is a standard therapy option in many cancer types. Recently, improved effects were observed when radiation therapy was combined with immunotherapy such as immune checkpoint inhibitors. Indeed, radiation therapy has a systemic immunomodulatory effect by stimulating cancer immunity cycle through the release of cancer antigens and improving immune infiltration. Besides,...

40. Influence of Image Resolution and Extraction Software on the Stability of Radiomic Features

Lars Widmer (Universität Zürich)

27/10/2022, 14:25

Miscellaneous

Oral

Purpose

Before the extraction of radiomic features, images are usually interpolated to a common resolution. Furthermore, a number of different radiomic feature extraction software exist. Here, we investiage how choice of interpolation resolution and feature extraction software affects stability of radiomic features.

Methods

Following work quantifies this influence on the radiomic...

30. Magnetic Resonance Imaging Radiomic Features Stability in Brain Metastases

Zahra Khodabakhshi (University of Zurich)

27/10/2022, 14:35

Diagnostics

Oral

Purpose:
In radiomic studies, robustness of models can be challenging due to variations in feature values caused by different scanners and imaging protocols. This problem is most prominent in magnetic resonance imaging (MRI) due its high sensitivity to imaging parameters. This study aims to assess the impact of image preprocessing, and image-normalization on the stability of MRI-based...

32. PET/CT radiomics for prediction of hyperprogression in metastatic melanoma patients treated with immune checkpoint inhibitors

Hubert Gabrys (University Hospital of Zürich)

27/10/2022, 14:45

Miscellaneous

Oral

Purpose: This study evaluated pretreatment FDG-PET/CT-based radiomic signatures for prediction of hyperprogression in metastatic melanoma patients treated with immune checkpoint inhibition (ICI).

Material and method: 56 consecutive metastatic melanoma patients treated with ICI and available imaging were included in our study and 330 metastatic lesions were individually segmented on...

20. Feasibility and mechanical accuracy of gated dynamic trajectory radiotherapy

Mr Hannes Anton Loebner (Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland)

27/10/2022, 14:55

Radiation Therapy

Oral

Purpose: To experimentally assess the technical feasibility and quantify the mechanical accuracy of respiratory gating during dynamic trajectory radiotherapy (DTRT) plan delivery. DTRT extends VMAT by dynamic table and collimator rotation during beam-on.

Methods: An HexaMotion motion stage positioned on the treatment table of a TrueBeam system is used to reproduce four different...

13. Influence of two-level quality assurance methodology on safety margins size and planning target volumes in frameless mask-based image-guided stereotactic intracranial radiosurgery and radiotherapy.

Dr Sergejs Popovs (Institute for Radiotherapy, Radiotherapie Hirslanden AG)

27/10/2022, 15:05

Radiation Therapy

Oral

Purpose
To estimate influence of adding tolerance levels (TL) to ultimate action levels (AL) in quality control (QC) of equipment geometrical precision in stereotactic radiotherapy on size of safety margins (SMs) and, consequentially, planning target volumes (PTVs) in frameless image-guided stereotactic intracranial radiosurgery and radiotherapy (SRS/SRT) delivered with the Accuray...