Comparative analysis of [¹⁸f]-fdg pet-ct and contrast-enhanced CT for target volume delineation in radiotherapy planning of head and neck cancers

Background

Target volume delineation in radiotherapy planning (RTP) for head and neck cancers is conventionally based on contrast-enhanced computed tomography (CECT). [¹⁸F]-FDG PET-CT adds functional (metabolic) information to anatomical imaging and may alter both the delineated tumour volume and the clinical stage. The objective is to compare and quantify the gross tumour volume (GTV) delineated on [¹⁸F]-FDG PET-CT with that delineated on CECT in head and neck cancers, and to assess the impact of PET-CT on TNM staging and RT planning. Materials and Methods: In this prospective observational study, 52 patients with biopsy-proven or clinically suspected head and neck carcinoma planned for radiotherapy (15 nasopharyngeal, 23 oropharyngeal/oral cavity, 14 laryngopharyngeal/laryngeal) underwent simulation CECT followed by PET-CT in the treatment position. Primary tumour and nodal volumes were contoured separately on CECT and on PET-CT (qualitative visual method) using a treatment planning system, and GTVs were compared using paired-sample statistics.