Introduction Breast radiotherapy in low-and-middle-income countries (LMICs) must balance target coverage, organ-at-risk (OAR) sparing, and workflow efficiency in resource-limited environments. This is pronounced in large or pendulous breasts treated on flattening-filter-free (FFF) linear accelerators (LINACs), where beam characteristics and larger fields can complicate dose homogeneity. This study compared the dosimetric performance and planning efficiency of breast radiotherapy techniques on a Halcyon platform. Materials and methods Thirty patients with large breast anatomy (separation >25 cm) were replanned using 3D conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT) with two- and four fields (IMRT4F), volumetric modulated arc therapy (VMAT), and VMAT with butterfly fields (VMATBF). Corresponding AutoPTV-based plans, generated from 3DCRT isodose contours, were also evaluated. Plans were generated in Eclipse v15.6 using Anisotropic Analytical Algorithm for delivery on a Halcyon 2.0 LINAC (40.05 Gy in 15 fractions). Target coverage, homogeneity, conformity, near-maximum dose and heart and lung OAR metrics were assessed. Planning efficiency and learning effects were evaluated using recorded planning times. Statistical analysis used one-way ANOVA with Tukey post-hoc testing (p 0.05). Conclusion AutoPTV IMRT4F represents a clinically feasible and resource-appropriate approach for large-breasted patients treated on Halcyon systems in LMIC settings, providing robust dosimetric performance with improved workflow efficiency.
Groenewald et al. (Wed,) studied this question.