Abstract Background Proton beam therapy is promising for the treatment of head and neck cancer (HNC). but it is sensitive to uncertainties in patient positioning and particle range. Studies have shown that the planning target volume (PTV) concept may not be sufficient to ensure robustness of the target coverage. A few planning studies have considered irradiation of unilateral HNC targ... https://mabelandfoxs.shop/product-category/stacking-toy/