assessment of dose distribution and organ-at-risk exposure in vmat versus 3d-crt for right breast cancer

Introduction: breast cancer is one of the most common malignant tumors worldwide, and radiotherapy plays a crucial role in its treatment. this study compares volumetric modulated arc therapy (vmat) and three-dimensional conformal radiotherapy (3d-crt) for right-sided breast cancer treatment, focusing on dosimetric parameters.material and methods: this retrospective study included 20 patients with right breast cancer treated at the international hospital of khouribga (mean age 52.4 ± 4.9 years; mean body mass index (bmi) 27.2 ± 1.1 kg/m²). for each patient, two treatment plans were generated: vmat with dual coplanar arc configuration and 3d-crt with opposed tangential beams. analyzed parameters included target volume coverage and doses to organs at risk. results: vmat provided superior target coverage and dose conformity. the mean homogeneity index (hi) was lower with vmat (0.08 ± 0.02) than 3d-crt (0.14 ± 0.02), and the conformity index (ci) was higher (0.99 ± 0.01 vs. 0.96 ± 0.02). mean heart dose was 4.9 ± 0.7 gray (gy) with vmat versus 1.0 ± 0.2 gy with 3d-crt; ipsilateral lung mean dose was 13.7 ± 1.5 gy versus 11.9 ± 0.7 gy, respectively. contralateral organs received higher low-dose exposure with vmat. vmat achieved improved planning target volume (ptv) coverage and conformity, whereas 3d-crt provided better contralateral organ sparing. conclusion: this study demonstrates vmat's dosimetric advantages over 3d-crt for breast cancer treatment, providing institutional validation for technique selection in resource-limited settings.