ESTRO 2024 - Abstract Book

S5499

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

ESTRO 2024

3. Mancosu P, Fogliata A, Stravato A, Tomatis S, Cozzi L, Scorsetti M. Accuracy Evaluation of the Optical Surface Monitoring System on EDGE Linear Accelerator in a Phantom Study. Med Dosim (2016) 41(2):173–9. doi:10.1016/j.meddos.2015.12.003

4. Ma Z , Zhang W , Yi S , et al. Optical Surface Management System for Patient Positioning in Interfractional Breast Cancer Radiotherapy[J]. BioMed Research International,2018,(2018-1-9), 2018, 2018:1-8.

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Digital Poster

The treatment quality of SG-DIBH on postmastectomy left breast cancer radiotherapy patients

Bei Kuang, Sufen Deng, Jinhua Zou

Southern Medical University Nanfang Hospital, Radiation Oncology, Guangzhou, China

Purpose/Objective:

The application of SG-DIBH (surface-guided deep inspiration breath hold) on breast intact cancer patients has been widely used due to good surface topography. However, the surface of mastectomy breast cancer patients is rather flat and less topographic. It adds the challenges when it comes to DIBH technique. Hence, we would like to evaluate the DIBH treatment quality of mastectomy patients using surface guided technology.

Material/Methods:

20 postmastectomy left breast cancer patients were selected via internal DIBH coaching program. During setup procedure, radiotherapists applied first ‘Move Couch’ function using SGRT system for free breathing surface (a.k.a baseline) position in 6 degrees of freedom. Second ‘Move couch’ was applied when the patient took a deep breathe in and matched with DIBH surface in vertical direction. The overall positioning accuracy, reproducibility of cardiac position (in 3DoF) and breath hold volumes (spine and sternum position) were analyzed using CBCT images.

Results:

There were total of 165 CBCT images were acquired. The absolute overall positioning accuracy was (0.20±0.15)cm , (0.19±0.15)cm , (0.18±0.15)cm and (0.84±0.76)°, (0.77±0.62)°, (0.95±0.77)° in longitudinal (LNG), lateral (LAT), vertical (VRT), yaw, pitch and roll directions. There was 82.42%, 86.06%, 86.67%, 90.30%, 96.97% and 90.91% in LNG, LAT, VRT, yaw, pitch and roll directions were within 3mm and 2°. The cardiac position accuracy was recorded as (0.18±0.12)cm, (0.17±0.11)cm and (0.19±0.09)cm in LNG, LAT and VRT directions. However, it was discovered that there were 5 CBCT images of 3 patients were significantly difference in terms of cardiac and diaphragm reproducibility compared to CT images and 1 patient was re-CT due to cardiac mismatched. It was suggested highly correlated to patient breathing patterns changed. The vertical differences between spine and sternum indicated the breath hold reproducibility. The mean and standard deviations of breath hold reproducibility were -0.03±0.20 cm and 86.40% was well within 3mm deviations.