ESTRO 2024 - Abstract Book

S5471

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

Negoro Y, Nagata Y, Aoki T, Mizowaki T, Araki N, Takayama K, Kokubo M, Yano S, Koga S, Sasai K, Shibamoto Y, Hiraoka M. The effectiveness of an immobilization device in conformal radiotherapy for lung tumor: reduction of respiratory tumor movement and evaluation of the daily setup accuracy. Int J Radiat Oncol Biol Phys. 2001 Jul 15;50(4):889-98. doi: 10.1016/s0360-3016(01)01516-4. PMID: 11429216.

NCCN Guidelines Version 3.2022 for Non-Small Cell Lung Cancer

Blandin Knight S, Crosbie PA, Balata H, Chudziak J, Hussell T, Dive C. Progress and prospects of early detection in lung cancer. Open Biol. 2017 Sep;7(9):170070. doi: 10.1098/rsob.170070. PMID: 28878044; PMCID: PMC5627048.

Oates R, Jones D, Foroudi F, Gill S, Ramachandran P, Schneider M, Lim Joon M, Kron T. Geographical miss of the prostate during image-guided radiotherapy with a 6-mm posterior expansion margin. J Med Radiat Sci. 2017 Jun;64(2):97-105. doi: 10.1002/jmrs.186. Epub 2016 Nov 8. PMID: 27860454; PMCID: PMC5454331. Altorki NK, Markowitz GJ, Gao D, Port JL, Saxena A, Stiles B, McGraw T, Mittal V. The lung microenvironment: an important regulator of tumour growth and metastasis. Nat Rev Cancer. 2019 Jan;19(1):9-31. doi: 10.1038/s41568-018 0081-9. PMID: 30532012; PMCID: PMC6749995.

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Digital Poster

Evaluation of stability of intracranial mask systems: Brainlab versus DSPS masks

Sjoerd Y Hoek, Johan P Cuijpers

Amsterdam UMC, Radiotherapy, Amsterdam, Netherlands

Purpose/Objective:

Due to the merge of two radiotherapy departments the use of Brainlab’s double-sided thermoplastic masks (Brainlab AG, Munich, Germany) for intracranial stereotactic treatments was replaced by the Double Shell Positioning System (DSPS, Macromedics holding, Moordrecht, the Netherlands) in order to achieve harmonization in positioning devices. Literature [1,2] suggested comparable sub-millimeter stability for both mask types, this was verified by analyzing the setup data for both types of mask systems.

Material/Methods:

A retrospective analysis was conducted comparing the anterior-posterior (AP), cranio-caudal (CC), left-right (LR), pitch, roll, yaw and 3D vector corrections from online image-guided setup data. 105 Brainlab mask patients with 305 fractions and 78 DSPS mask patients with 444 fractions treated on a Truebeam (Varian Medical Systems, Palo Alto, USA) with a 6 degrees of freedom (6Dof) couch were included. The initial setup consisted of kV-kV imaging followed by a 6Dof couch correction after which online CBCT guided correction was performed to correct for residual setup errors. Optional verification CBCTs before treatment were made when the residual shifts exceeded 0.05 cm or 0.5°. Mid-treatment CBCTs were performed for all single fraction treatments. The range and standard deviation (SD) of all