55th SSRMP Annual Meeting

Session

Session I: QA, Dosimetry, Treatment Planning

27 Oct 2022, 10:15

Lachensaal & Foyer (Kultur- und Kongresszentrum Thun)

5. A Comparison of Two Approaches for Checking the Source Positioning Accuracy in Brachytherapy

Michael Baumgartl

27/10/2022, 10:15

Radiation Therapy

Oral

Purpose:
In brachytherapy remote afterloaders are used to transfer a radioactive source via transfer tubes to applicators or interstitial needles with submillimetre accuracy. Predefined dwell positions and dwell times of the source define the dose distribution to aim for interior/superficial target volumes. A high dose is delivered over a small amount of fractions and a large offset of the...

36. Comparing dry-run and delivery modes for dynamic trajectory radiotherapy

Paul-Henry Mackeprang

27/10/2022, 10:25

Radiation Therapy

Oral

Purpose
Dynamic trajectory radiotherapy (DTRT) extends VMAT with dynamic table and collimator rotations during beam-on. Dry-runs are needed for safety purposes, as for example to check treatment plans for potential collisions. This study investigates if DTRT dry-runs accurately simulate the machine motion of DTRT via log-file analysis.

Methods
Eight DTRT treatment plans for...

22. Development of a collision prediction tool using Blender for non-coplanar radiotherapy on a C-arm linear accelerator

Gian Guyer (Division of Medical Radiation Physics, Inselspital)

27/10/2022, 10:35

Radiation Therapy

Oral

Purpose: Non-coplanar treatment techniques on a C-arm linear accelerator have the potential to improve treatment plan quality in comparison to conventional coplanar volumetric modulated arc therapy (VMAT). During treatment planning of dynamic trajectory radiotherapy (DTRT), which extends VMAT by dynamic couch rotation, it is essential to know the gantry and table angle combinations leading to...

33. CyberKnife Preliminary Commissioning Model for a Twinned Beam

Valery Taranenko (Accuray)

27/10/2022, 10:45

Radiation Therapy

Oral

Purpose
To establish a beam twinning procedure and develop a model for accelerated TPS commissioning for all three collimators of CyberKnife M6 & S7 models.

Methods
Beam twinning was performed in two phases: initially with PTW Octavius 1000 SRS 2D panel with real-time feedback, then in 3D water tank with PTW SemiFlex 3D 0.3 cc chamber for cone-60 (0-300 mm PDD, 50 mm profiles) and the...

41. Calculation of dosimetric parameters in paediatric phantoms using Monte Carlo techniques for 18F-FDG and the new TIAC

Ms Carlos Vinícius Gomes Ferreira (Universidade Federal de Minas Gerais)

27/10/2022, 10:55

Nuclear Medicine

Oral

Purpose: In nuclear medicine, one of the most used radiopharmaceutical is $^{18}$F-FDG, administered in paediatric and adult patients considering the same time-integrated activity coefficient (TIAC). Although, the IAEA recommends specific paediatric dosimetry. The objective of this work was to estimate the absorbed dose per injected activity and effective dose per injected activity for the...

39. Assessing the robustness of normal tissue complication probability of head and neck treatment plans to contouring uncertainties

Mrs Lisa Stefanie Fankhauser (1) Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland 2) Institute for Biomedical Engineering, ETH Zürich and PSI, Villigen, Switzerland.)

27/10/2022, 11:05

Radiation Therapy

Oral

Purpose
To assess the robustness of normal-tissue complication probability (NTCP) scores for xerostomia and dysphagia in treatment plans for head and neck squamous cell carcinoma (HNSCC) using volumetric modulated arc therapy (VMAT) and dynamic trajectory radiotherapy (DTRT) to contouring uncertainties.

Methods
In order to assess robustness of NTCP scores, an in-house developed...

4. Clinical implementation of machine learning autoplanning for breast treatments: the CHUV recipe

Michele Zeverino (CHUV)

27/10/2022, 11:15

Radiation Therapy

Oral

Purpose: To report a general framework for the clinical implementation of a machine learning (ML) autoplanning model in RayStation (RS) TPS.
Methods: ML autoplanning was developed for left-sided breast patients under deep-inspiration breath-hold treated with a double-arc VMAT technique. Different ML models (M) were built for two SIB prescriptions, 60/50Gy (M1) and 48/42.4Gy (M2),...

16. Development of a lexicographic automatic intensity optimization process

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, 11:25

Radiation Therapy

Oral

Purpose: To develop an automatic intensity optimization (AIO) process for volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT), using the Eclipse scripting API (ESAPI).

Methods: A multi-round and multi-group lexicographic optimization process is developed interfacing the Eclipse treatment planning system via ESAPI.

The input of the AIO process is...