Comparison of Volumetric Quantitative PET Parameters Before and After a CT-Based Elastic Deformation on Dual-Time 18FDG-PET/CT Images: A Feasibility Study in a Perspective of Radiotherapy Planning in Head and Neck Cancer

Frontiers in Medicine

article

Meriem Maajem¹  Jean-Christophe Leclère²  David Bourhis¹  Valentin Tissot⁴  Nicolas Icard⁵  Laëtitia Arnaud⁵  Romain Le Pennec¹  Gurvan Dissaux⁶  Dorothy M. Gujral⁷  Pierre-Yves Salaün¹  Ulrike Schick⁶  Ronan Abgral¹ 

[1] Department of Nuclear Medicine, Brest University Hospital;Department of Oto-Rhino-Laryngology, Brest University Hospital;European University of Brittany;Department of Radiology, Brest University Hospital;Department of Nuclear Medicine, Saint-Brieuc Regional Hospital;Department of Radiotherapy, Brest University Hospital;Clinical Oncology Department, Imperial College Healthcare National Health Service ,(NHS) Trust, Charing Cross Hospital;Department of Cancer and Surgery, Imperial College London

关键词: elastic registration;    dual time 18FDG-PET/CT images;    radiotherapy planning;    head neck cancer;    gradient based method;   

DOI  :  10.3389/fmed.2022.831457

学科分类：社会科学、人文和艺术（综合）

来源: Frontiers

【 摘 要 】

Background The use of 18FDG-PET/CT for delineating a gross tumor volume (GTV, also called MTV metabolic tumor volume) in radiotherapy (RT) planning of head neck squamous cell carcinomas (HNSCC) is not included in current recommendations, although its interest for the radiotherapist is of evidence. Because pre-RT PET scans are rarely done simultaneously with dosimetry CT, the validation of a robust image registration tool and of a reproducible MTV delineation method is still required. Objective Our objective was to study a CT-based elastic registration method on dual-time pre-RT 18FDG-PET/CT images to assess the feasibility of PET-based RT planning in patients with HNSCC. Methods Dual-time 18FDG-PET/CT [whole-body examination (wbPET) + 1 dedicated step (headPET)] were selected to simulate a 2-times scenario of pre-RT PET images deformation on dosimetry CT. ER-headPET and RR-headPET images were, respectively, reconstructed after CT-to-CT rigid (RR) and elastic (ER) registrations of the headPET on the wbPET. The MTVs delineation was performed using two methods (40%SUVmax, PET-Edge). The percentage variations of several PET parameters (SUVmax, SUVmean, SUVpeak, MTV, TLG) were calculated between wbPET, ER-headPET, and RR-headPET. Correlation between MTV values was calculated (Deming linear regression). MTVs intersections were assessed by two indices (OF, DICE) and compared together (Wilcoxon test). Additional per-volume analysis was evaluated (Mann-Whitney test). Inter- and intra-observer reproducibilities were evaluated (ICC = intra-class coefficient). Results 36 patients (30M/6F; median age = 65 y) were retrospectively included. The changes in SUVmax, SUVmean and SUVpeak values between ER-headPET and RR-headPET images were 0.99). The ER-headPET MTVs had significant higher mean OF and DICE with the wbPET MTVs, for both delineation methods ( p ≤ 0.002); and also when lesions had a volume > 5cc (excellent OF = 0.80 with 40%SUVmax). The inter- and intra-observer reproducibilities for MTV delineation were excellent (ICC ≥ 0.8, close to 1 with PET-Edge). Conclusion Our study demonstrated no significant changes in MTV after an elastic deformation of pre-RT 18FDG-PET/CT images acquired in dual-time mode. This opens possibilities for HNSCC radiotherapy planning improvement by transferring GTV-PET on dosimetry CT.

【 授权许可】

CC BY