Dosimetric and isocentric variations due to patient setup errors in CT-based treatment planning for breast cancer by electronic portal imaging
| Autor: | Kirti Tyagi, Hari Mukundan, Samaresh Sahu, Subhash Ranjan, Deboleena Mukherjee, Sachin Taneja |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Systematic error Reproducibility business.industry medicine.medical_treatment 030106 microbiology General Medicine medicine.disease Radiation therapy Surface distance 03 medical and health sciences 0302 clinical medicine Breast cancer Portal imaging Digitally reconstructed radiographs medicine Original Article 030212 general & internal medicine Nuclear medicine business Radiation treatment planning |
| Zdroj: | Med J Armed Forces India |
| ISSN: | 0377-1237 |
| DOI: | 10.1016/j.mjafi.2018.07.008 |
| Popis: | Background Inaccuracies in treatment setup during radiation therapy for breast cancers may increase risks to surrounding normal tissue toxicities, i.e. organs at risks (OARs), and compromise disease control. This study was planned to evaluate the dosimetric and isocentric variations and determine setup reproducibility and errors using an online electronic portal imaging (EPI) protocol. Methods A total of 360 EPIs in 60 patients receiving breast/chest wall irradiation were evaluated. Cumulative dose–volume histograms (DVHs) were analyzed for mean doses to lung (V20) and heart (V30), setup source to surface distance (SSD) and central lung distance (CLD), and shifts in anterior-posterior (AP), superior-inferior (SI), and medial lateral (ML) directions. Results Random errors ranged from 2 to 3 mm for the breast/chest wall (medial and lateral) tangential treatments and 2–2.5 mm for the anterior supraclavicular nodal field. Systematic errors ranged from 3 to 5 mm in the AP direction for the tangential fields and from 2.5 to 5 mm in the SI and ML direction for the anterior supraclavicular nodal field. For right-sided patients, V20 was 0.69–3.96 Gy, maximum lung dose was 40.5 Gy, V30 was 1.4–3 Gy, and maximum heart dose was 50.5 Gy. Similarly, for left-sided patients, the CLD (treatment planning system) was 25 mm–30 mm, CLD (EPIs) was 30–40 mm, V20 was 0.9–5.9 Gy, maximum lung dose was 45 Gy, V30 was 2.4–4.1 Gy, and maximum heart dose was 55 Gy. Conclusion Online assessment of patient position with matching of EPIs with digitally reconstructed radiographs (DRRs) is a useful method in evaluation of interfraction reproducibility in breast irradiation. |
| Databáze: | OpenAIRE |
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