Nasal cavity and paranasal sinus cancers are relatively rare and account for about 5% of head and neck cancers. Diagnosis often occurs in the later stages for the majority of patients, given that symptoms and signs tend to be nonspecific or absent during the early phases. In cases of locally advanced nasal cavity and paranasal sinus cancer, the standard treatment involves surgery followed by postoperative radiotherapy or definitive radiotherapy with or without chemotherapy[1].

In locally advanced stage, complete resection may not be possible due to the proximity to critical organs, and postoperative or definitive radiotherapy is needed. Compared to traditional 2D or 3D treatment plans, non-coplanar Intensity-Modulated Radiotherapy (IMRT) or Volumetric Modulated Arc Therapy (VMAT) provides a more sophisticated dose distribution to the target area while minimizing radiation exposure to adjacent critical organs such as the eyes, lenses, optic nerves, optic chiasm, brain stem and pituitary[2]. These advanced treatment modalities overcome the challenges posed by the proximity of critical organs, allowing for optimal dose coverage to the target region and simultaneously reducing the radiation dose to important surrounding structures.

The primary aim of this investigation is to conduct a dosimetric comparison among three distinct techniques: Halcyon Volumetric Modulated Arc Therapy (VMAT), Intensity-Modulated Radiation Therapy (IMRT), and Linac Novalis non-coplanar IMRT.