Dosimetric comparison study of intensity modulated radiotherapy technique (IMRT/VMAT) with three dimensional field-in-field tangents for left breast cancer irradiation

Abstract

Purpose: To retrospectively compare dosimetrically three dimensional field-in-field tangents (3D F-in-F), Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) left breast irradiation plans. Materials and Methods: A total of 30 patients were included in this study. All patients diagnosed with early–stage malignant neoplasm of the breast prior to treatment. Patients were contoured with three main PTV-Chest wall (PTVCW), PTV-Axilla (PTVAX), and PTV-IMC (PTVIMC). Monaco treatment planning system was used to create the plans. For each patient, three treatment plans were created; three dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). The dose coverage of PTVs and the dose constraints of Organ-at-Risks (OARs) were compared and analyzed. Results: The dose objective to cover the PTVs; PTVCW, PTVAX, and PTVIMC were V40.43Gy (95%) ≥ 95%, V38.3Gy (90%) ≥ 95%, and V34.05Gy (80%) ≥ 95% respectively. Comparing the dose coverage of PTVCW between 3D-CRT and VMAT, resulted in a significant difference (P= 0.003) and the VMAT was superior for the coverage of target than 3D-CRT. For PTVAX, the coverage was 45.80±0.55, 45.96±0.73, and 45.58±0.63 for 3D-CRT, IMRT, and VMAT respectively. For PTVIMC, the coverage was 45.80±0.55, 45.96±0.73, and 45.58±0.63 for 3D-CRT, IMRT, and VMAT respectively.