ESTRO 2024 - Abstract Book

S5454

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

ESTRO 2024

133

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Breathing Amplitude Variations in Left Breast Radiotherapy using Surface-Guided DIBH Technique.

Abid Ali Mirza aman, Amna abdullah Al-Ajmi, Nadeem Pervez

Sultan Qaboos comprehensive cancer care and research centre, Radiation Oncology, Muscat, Oman

Purpose/Objective:

Radiation therapy is vital for managing left breast and chest wall cancers. Precise radiation delivery, while minimizing healthy tissue exposure, is crucial. The Deep Inspiration Breath Hold (DIBH) technique, combined with Surface Guided Radiation Therapy (SGRT), is used. DIBH involves breath-holding in deep inspiration, increasing target-to-heart distance and reducing heart dose. SGRT monitors breathing amplitude, the chest wall's expansion during breath hold, crucial for maintaining target positioning. This study examines breathing amplitude variations during DIBH and SGRT for left breast patients across pre-simulation, CT-simulation, and treatment phases. Assessing reproducibility aids treatment optimization. Insights could refine protocols, enhance accuracy, and improve patient outcomes. DIBH, guided by SGRT, ensures effective treatment for left breast cancer patients.

Material/Methods:

A retrospective study examined 32 left breast/chest wall cancer patients in the Radiotherapy department. Patients were trained in Deep Inspiration Breath Hold (DIBH) before CT-SIM, with breathing amplitude monitored using SGRT Live Monitoring. PSE, CT-SIM, and on-treatment amplitudes were recorded from September 2022 to April 2023. Statistical analysis yielded amplitude ranges: PSE Education (0.63 cm to 1.51 cm), At CT-Sim (0.61 cm to 1.55 cm), and Daily RT (0.21 cm to 0.912 cm). The average standard deviation during RT was 0.409 cm, with a range of 0.06-0.63.

Results:

The analysis of amplitude variation from Pre-CT Training to the Treatment phase yielded an average standard deviation of 0.409 cm. This value surpasses the departmental threshold of 0.3 cm, indicating a notable level of variability beyond the acceptable limits.

Conclusion:

Currently, we are in the process of standardizing the Region of Interest (ROI) structure set and position of ROI in CT Education, CT-SIM, and treatment using the SGRT system. This standardization will improve our surface tracking. However, we have a limitation in pre-CT education and CT-SIM, as the dimensions of the tracker are 5x5. For ongoing RT treatment, the dimensions are user-dependent.

Keywords: SGRT,DIBH,Amplitude Variation