18F-Fdg-PET-guided Planning and Re-Planning (Adaptive) Radiotherapy in Head and Neck Cancer: Current State of Art

Purpose The aim of the study was to evaluate the usefulness and accuracy of 18-fluorine-labeled fluorodeoxyglucose (PET) and magnetic resonance imaging (MRI) hybrid in gross tumor volume (GTV) delineation during radiotherapy planning in patients with carcinoma of the tongue. Methods Ten patients with squamous cell carcinoma (SCC) of the tongue underwent computed tomography (CT) and PET/MRI examination. The GTV for primary tumor and lymph nodes (nGTV) were defined on CT (GTV-CT) and compared to GTVs obtained from PET (GTV-PET) and MRI (GTV-MRI) images. Two methods of GTV determination were used: visual interpretation of CT, PET (GTV-PET vis ) and MRI images and quantitative automatic method (Syngovia, Siemens) based on a chosen threshold value (20%, 30%, 40%, 50%) of standardized uptake values (SUV max ) from PET examination (GTV-PET 20% , GTV-PET 30% , etc.). Statistical analysis of differences in GTV values obtained from CT, PET and MRI studies was performed. GTV-CT was used as a reference. Results In all, 80% of GTV-MRI and 40% of GTV-PET vis were larger than GTV-CT. Respectively, 20% of GTV-MRI and 60% of GTV-PET vis were smaller than GTV-CT. Taking into account all threshold measurements, 70% of volumes were smaller than GTV-CT. GTV-PET 30% were the most closely related volumes to GTV-CT from all threshold methods in 50% of patients. GTV-PET vis generated the most similar volumes in relation to GTV-CT from all PET measurements. Statistical analysis confirmed those results. Compared to nGTV-CT, 70% of nGTV-MRI and 20% of nGTV-PET vis were larger. The remaining nGTV-MRI and nGTV-PET vis measurements were smaller than nGTV-CT. Measurements of all thresholds nGTVs were smaller than nGTV-CTV in 52.5% of cases. nGTV-PET 20% were the most closely related volumes to nGTV-CT in 40% of the cases. Statistical analysis showed that nGTV-PET 20% ( p = 0.0468), nGTV-PET vis ( p = 0.0166), and nGTV-PET 50% ( p = 0.0166) diverge significantly from nGTV-CT results. nGTV-MRI ( p = 0.1141), nGTV-PET 30% ( p = 0.2845), and nGTV-PET 40% ( p = 0.5076) were significantly related with nGTV-CT. Conclusion Combination of PET/MRI provides more information during target tumor mass delineation in radiotherapy planning of patients with SCC of the tongue than other standard imaging methods. The most frequently matching threshold value was 30% of SUV ...

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“…Head and neck cancers (HNC) are the sixth most common malignancy in the world [1]. Squamous cell carcinoma (SCC) is the major histology.…”

Section: Introductionmentioning

confidence: 99%

PET/MRI-guided GTV delineation during radiotherapy planning in patients with squamous cell carcinoma of the tongue

Samołyk-Kogaczewska¹,

Sierko

Zuzda

et al. 2019

Strahlenther Onkol

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“…Structure definition can be challenging on CT due to low contrast compared to other imaging modalities such as MRI. Including multiple imaging modalities for contouring can lead to a reduction in inter-observer variability (Caldwell et al 2001 , Farina et al 2017 , Hall et al 2018 ). Though it is common to merge CT with PET, MRI or other images for contouring, the effect of deformable registration errors is not well investigated.…”

Section: Application-specific Dir Uncertaintymentioning

confidence: 99%

Review and recommendations on deformable image registration uncertainties for radiotherapy applications

Nenoff,

Amstutz,

Murr

et al. 2023

Phys. Med. Biol.

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Deformable image registration (DIR) is a versatile tool used in many applications in radiotherapy (RT). DIR algorithms have been implemented in many commercial treatment planning systems providing accessible and easy-to-use solutions. However, the geometric uncertainty of DIR can be large and difficult to quantify, resulting in barriers to clinical practice. Currently, there is no agreement in the RT community on how to quantify these uncertainties and determine thresholds that distinguish a good DIR result from a poor one. This review summarises the current literature on sources of DIR uncertainties and their impact on RT applications. Recommendations are provided on how to handle these uncertainties for patient-specific use, commissioning, and research. Recommendations are also provided for developers and vendors to help users to understand DIR uncertainties and make the application of DIR in RT safer and more reliable.

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“…However, the use of 18FDG-PET/CT for delineating the gross tumor volume (GTV) in radiotherapy (also called metabolic tumor volume MTV) is not included in current recommendations although its interest for the radiotherapist is of clinical relevance (12,13). Some studies have shown that the GTV delineation in PET improved inter-and intra-observer reproducibility compared to CT (14), while having a better concordance with the macroscopic tumor volume.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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BackgroundThe 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.ObjectiveOur 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.MethodsDual-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).Results36 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 <5%. The variations in MTV values between ER-headPET and wbPET images were −6 and −3% with 40%SUVmax and PET Edge, respectively. Their correlations were excellent whatever the delineation method (R2 > 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).ConclusionOur 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.

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18F-Fdg-PET-guided Planning and Re-Planning (Adaptive) Radiotherapy in Head and Neck Cancer: Current State of Art

Cited by 4 publications

References 42 publications

PET/MRI-guided GTV delineation during radiotherapy planning in patients with squamous cell carcinoma of the tongue

PET/MRI-guided GTV delineation during radiotherapy planning in patients with squamous cell carcinoma of the tongue

Review and recommendations on deformable image registration uncertainties for radiotherapy applications

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

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