Evaluation of spatial correlation of external beam radiotherapy and interstitial brachytherapy with deformable image registration (DIR)-based dose summation in early head and neck squamous cell carcinoma
Year: 2025
Type: article
Abstract: Purpose: Oral cavity squamous cell carcinoma (SCC) is conventionally treated with surgery followed by adjuvant radiation therapy.Multiple studies have demonstrated clinical utility of interstitial brachytherapy (BT) alone or external beam radiotherapy (EBRT) with BT boost for T1-T2N0 cancers of lip and buccal mucosa.In case of combined EBRT and BT, dose summation and optimizing doses received by planning target volume (PTV) and organs at risk (OARs) remains challenging.The aim of this study was to generate and evaluate dosimetric parameters of PTV and OARs as a sum of high-doserate (HDR)-BT boost and EBRT in early T1-T2N0 cancers of lip and buccal mucosa, using deformable image registration (DIR) software (Velocity ® ). 2 Gy equivalent dose (EQD 2 ) calculated manually (EQD 2 -D 90 BT + EQD 2 -D 98 EBRT) was compared with that estimated using DIR.Material and methods: An analysis was performed in patients with histopathologically proven T1-T2N0 SCC of lip and buccal mucosa, who underwent interstitial BT boost followed by EBRT.Planning computed tomography (CT) images and respective treatment plans of both BT and EBRT were imported into Velocity ® software, and DIR was employed to fuse these images for all patients.A synthetic plan incorporating both plans was generated.Dosimetric parameters of both PTV and OAR (mandible) were analyzed.Results: This study included a total of 10 patients (cT1N0: n = 6, and cT2N0: n = 4), with median age of 57 years (range, 30-69 years) and male : female ratio of 7 : 3. The median dose to PTV using HDR-BT was 21 Gy (range, 20-21 Gy), delivered in 5-6 fractions, 3.5-4 Gy per fraction.The median dose to PTV using EBRT was 44 Gy (range, 40-46 Gy), delivered in 20-23 fractions, 1.8-2 Gy per fraction.Conclusions: DIR software-based dose summation provides accurate dose delivery to target and OARs.If performed prospectively, it can potentially enable optimization of limiting the doses to critical OARs, thus, reducing post-RT morbidity.
Authors: Ashutosh Mukherji, Sambit S. Nanda, Shubham Dokania, Sanju Sanju, Ajay K. Choubey, Ninad H. Patil, Kaushik Kashyap, Ajay S. Krishnan, Pritam Mondal, Satyajit Pradhan
Institution: Mahamana Pandit Madan Mohan Malaviya Cancer Centre
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $269
OpenAlex ID: W4410743499