PRECISION OPTIMIZATION OF RADIOTHERAPY PLANNING FOR HEAD AND NECK TUMORS BASED ON THE INTEGRATION OF MULTIPARAMETRIC IMAGING DATA
Keywords:
head and neck tumors, IMRT, VMAT, PET/CT, target delineation, CTV–PTV margin, geometric uncertainty, radiation toxicity, precision radiotherapyAbstract
The aim of the study was to evaluate the clinical effectiveness and safety of multimodal radiotherapy planning for head and neck tumors through the integration of CT, MRI, and PET/CT imaging data. A prospective-retrospective comparative analysis included 22 patients treated with radical IMRT/VMAT (66–70 Gy). Two imaging protocols were compared: CT + MRI (n=15) and CT + MRI + PET/CT (n=7).
The integration of PET/CT reduced the systematic error (Σ) from 3.2 to 1.8 mm and the random error (σ) from 2.1 to 1.2 mm, resulting in a 43% reduction of the calculated CTV–PTV margin (from 9.3 to 5.4 mm). The high-dose volume (70 Gy) decreased by 28% (p<0.05), with significant dose reduction to the brainstem and spinal cord. No increase in severe radiation toxicity was observed. A significant correlation was found between the PTV 66–70 Gy volume and dysphagia (r=0.42; p<0.05), and a threshold relationship was identified between xerostomia and parotid mean dose >26 Gy.
Multimodal imaging-based planning with mathematically justified margin individualization enhances precision in radiotherapy and reduces toxicity without compromising oncological control.
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