Improvement in Coronary Dose Distribution Using Dynamic Swing Arc in Volumetric-modulated Arc Therapy During...

Area of Science:

• Radiation Oncology
• Medical Physics
• Cardiovascular Health

Background:

• Dose to the left anterior descending coronary artery (LAD) correlates with mortality in esophageal cancer (EC) patients receiving radiotherapy.
• Optimizing radiation delivery is crucial for improving outcomes and reducing toxicity.

Purpose of the Study:

• To compare the efficacy of dynamic swing arc in OXRAY (DSA-VMAT) versus conventional coplanar VMAT (Conv-VMAT) in delivering radiation dose to the LAD region.
• To assess the impact of DSA-VMAT on cardiac and pulmonary structures, as well as target volume coverage.

Main Methods:

• Retrospective analysis of 10 EC patients who underwent radiotherapy (60 Gy in 30 fractions).
• Creation of two virtual treatment plans: DSA-VMAT and Conv-VMAT.
• Comparative analysis of dose distributions to the LAD region, heart, lungs, and planning target volume (PTV) using paired t-tests.

Main Results:

• DSA-VMAT significantly reduced the LAD V15 (10.48% vs. 30.28%, p=0.01) and mean heart dose (8.64 Gy vs. 11.23 Gy, p<0.01).
• Significant reductions were also observed in heart V40, lung V20, and lung V5 with DSA-VMAT compared to Conv-VMAT (all p≤0.01).
• No significant differences were found in PTV dose coverage (D95, D50) or conformity index between the two planning techniques.

Conclusions:

• DSA-VMAT offers superior dose distribution to the LAD region and heart compared to Conv-VMAT in EC patients.
• This improved dosimetry is achieved without compromising PTV coverage, suggesting DSA-VMAT can reduce radiation-induced heart disease risk.
• DSA-VMAT represents a promising advancement for esophageal cancer radiotherapy, enhancing safety and efficacy.