Dosimetric impact of bolus thickness and immobilization mask use in postmastectomy radiotherapy: a chest wall thickness–based analysis

Both thermoplastic masks and bolus significantly affect PMRT dosimetry. Bolus provides improved PTV coverage and lung sparing at the cost of higher skin dose, while thermoplastic masks act as unintended compensators. Chest wall thickness strongly influences these effects, supporting individualized selection of bolus and mask use, particularly for patients with thinner chest walls.