Improving patient positioning and posture for breast cancer radiotherapy using DIBH and SGRT techniques - by modifying fixation devices and tightening SGRT tolerances

Q: What was the study’s main aim in breast cancer radiotherapy?

To investigate whether changing patient fixation devices and tightening SGRT tolerances reduces residual errors and interfractional positioning variability during DIBH radiotherapy for breast cancer.

Q: What modifications were made to the fixation devices and SGRT tolerances?

A 10° wedge-shaped foam cushion was introduced under the patient’s back and the knee wedge was rotated to support pelvic positioning more tightly; SGRT tolerance values were tightened from 8/12 mm to 5 mm.

Q: Which outcome showed improvement after the modifications?

Residual errors improved significantly at specific anatomical positions in kV images, and systematic pitch error decreased for both groups.

Sep 29, 2026

Uploaded by ahduag

Background: Surface guided radiotherapy (SGRT) supports accurate patient setup before radiotherapy. This retrospective observational study evaluates whether modifying patient fixation devices and tightening SGRT tolerances decreases residual setup errors and interfractional positioning variability in deep inspiration breath hold radiotherapy for breast cancer. Materials and methods: Fixation was adapted using a 10° wedge foam cushion and a revised knee wedge; SGRT tolerances were tightened to 5 mm. Results showed significant improvements in residual errors across multiple anatomical landmarks in kV images. Conclusions: The modifications improved patient position and pitch.

LanguageEnglish

CategoryHealthcare

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Abstract

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Materials and methods

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© 2025 Greater Poland Cancer Centre. Published by Via Medica. All rights reserved. e-ISSN 2083–4640 ISSN 1507–1367 ISSN: 1507–1367 RESEARCH PAPER Reports of Practical Oncology and Radiotherapy 2025, Volume 30, Number 5, pages: 589–598 DOI: 10.5603/rpor.107871 Submitted: 07.02.2025 Accepted: 31.07.2025 Improving patient positioning and posture for breast cancer radiotherapy using DIBH and SGRT techniques by modifying fixation devices and tightening SGRT tolerances Lauri Järvinen1, 2, Marko Laaksomaa3, Mikko Björkqvist1, 2, Jani Keyriläinen1, 2, 4 1Department of Medical Physics, Turku University Hospital and University of Turku, Turku, Finland 2Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland 3Department of Oncology, Tampere University Hospital, Tampere, Finland 4Department of Physics, Faculty of Science, University of Helsinki, Helsinki, Finland ABSTRACT Background: Surface guided radiotherapy (SGRT) aids to place the patient in the correct position before radiotherapy. The aim of this retrospective observational study was to investigate how modifying patient fixation devices and tightening SGRT tolerances reduces residual errors and interfractional positioning variability in patients’ position and posture for deep inspiration breath hold radiotherapy (RT) of breast cancer. Materials and methods: The patient fixation devices were changed by introducing a 10° wedge-shaped foam cushion under the patients’ back and rotating the previously used knee wedge to support the pelvic position more tightly. Additionally, the SGRT tolerance values were tightened from 8 or 12 mm to 5 mm. Patient Group A (n = 25) had had breast-conserving surgery and Group B (n = 25) mastectomy before RT. Residual errors of bony landmarks, breast outline and indicators of patient posture were retrospectively analyzed in a treatment planning system from 472 and 467 fractions before, and from 571 and 665 fractions after modifications for Groups A and B, respectively. Results: Statistically significant improvements (p < 0.05) in residual errors were found at the positions ofthe shoulder joint, T1 and T2 vertebrae (Group B), and the sternum (Groups A and B), as well as the rib cage (Group B) and the breast outline (Group A) in kV images. Systematic error for patient pitch decreased from 3.7 mm to 2.0 mm (Group A) and from 3.2 mm to 1.8 mm (Group B) (p < 0.05) . Conclusions: The modifications improved patients’ position and pitch. Keywords: surface-guided radiotherapy; breast cancer; deep inspiration breath-hold; radiotherapy; image-guidance Rep Pract Oncol Radiother 2025;30(5):589–598 Introduction Radiotherapy (RT) is a common form of breast cancer treatment due to its reduction of recurrence after surgery of the tumour as well as lymph nodes containing metastases [1] . In the surgery, either the breast tumour is removed with margins conserving the breast, or the entire breast is removed (mastectomy) . In locoregional disease, in addition to the breast or chest wall, supraclavicular lymph node regions are also irradiated. In this case, positioning of the moving shoulder joint and thoracic Address for correspondence: Lauri Järvinen, TYKS Turku University Hospital, Department of Medical Physics and Department of Radiation Oncology, P.O. Box 52 FIN-20521 Turku, Finland; [e-mail: lauri.jarvinen@varha.fi](e-mail: lauri.jarvinen@varha.fi) This article is available in open access under Creative Common Attribution-Non-Commercial-No Derivatives 4.0 International (CC BY-NC-ND 4.0) license, allowing to download articles and share them with others as long as they credit the authors and the publisher, but without permission to change them in any way or use them commercially [https://journals.viamedica.pl/rpor](https://journals.viamedica.pl/rpor) 589 spine must also be taken into account in the patient’s positioning [2]. In left breast RT, the deep inspiration breath hold (DIBH) techniques

FAQs

What was the study’s main aim in breast cancer radiotherapy?

To investigate whether changing patient fixation devices and tightening SGRT tolerances reduces residual errors and interfractional positioning variability during DIBH radiotherapy for breast cancer.

What modifications were made to the fixation devices and SGRT tolerances?

A 10° wedge-shaped foam cushion was introduced under the patient’s back and the knee wedge was rotated to support pelvic positioning more tightly; SGRT tolerance values were tightened from 8/12 mm to 5 mm.

Which outcome showed improvement after the modifications?

Residual errors improved significantly at specific anatomical positions in kV images, and systematic pitch error decreased for both groups.

Sep 29, 2026

Uploaded by ahduag