Radiation Dose to Critical Cardiac Structures from Three-Dimensional Conformal Radiation Therapy (3D-CRT), Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) Techniques for Left-Sided Breast Cancer

A comparison of the radiation exposure to the left anterior descending artery (LAD) and left ventricle (LV) was performed for twenty-three left breast cancer patients. For each participant, two tangential fields 3D-CRT, two- and seven-field IMRT and two and four partial arcs VMAT plans were created. Dose constraints for CTV, ipsilateral lung and heart were followed. The V_40Gy, V_30Gy, D_av of LAD and V_23Gy, V_5Gy, D_av of LV were calculated and extracted from the plans. Parametric and non-parametric tests were applied to compare the parameters derived from the five treatment techniques. All generated plans fulfilled the dose constraints. The D_av ranges of the LAD and LV from all examined techniques were 11.77-14.73 Gy and 5.37-6.40 Gy, respectively. The V_40Gy and V_30Gy ranges of the LAD were 2.90-12.91% and 10.80-18.51%, respectively. The V_23Gy and V_5Gy of the LV were 4.29-7.43% and 18.24-30.05%, respectively. The VMAT plans and seven-field IMRT significantly reduced the V_40Gy, V_30Gy of LAD and V_23Gy of LV compared with the two-field treatments (p < 0.05). However, 3D-CRT plans provided statistically lower values for V_5Gy of LV over the other techniques (p < 0.05). The presented results provide a detailed dataset of the radiation burden of two critical cardiac structures from five radiotherapy techniques.