An Adaptive Thresholding Method for BTV Estimation Incorporating PET Reconstruction Parameters: A Multicenter Study of the Robustness and the Reliability

Abstract

Objective. The aim of this work was to assess robustness and reliability of an adaptive thresholding algorithm for the biological target volume estimation incorporating reconstruction parameters. Method. In a multicenter study, a phantom with spheres of different diameters (6.5–57.4 mm) was filled with 18F-FDG at different target-to-background ratios (TBR: 2.5–70) and scanned for different acquisition periods (2–5 min). Image reconstruction algorithms were used varying number of iterations and postreconstruction transaxial smoothing. Optimal thresholds (TS) for volume estimation were determined as percentage of the maximum intensity in the cross section area of the spheres. Multiple regression techniques were used to identify relevant predictors of TS. Results. The goodness of the model fit was high (R 2: 0.74–0.92). TBR was the most significant predictor of TS. For all scanners, except the Gemini scanners, FWHM was an independent predictor of TS. Significant differences were observed between scanners of different models, but not between different scanners of the same model. The shrinkage on cross validation was small and indicative of excellent reliability of model estimation. Conclusions. Incorporation of postreconstruction filtering FWHM in an adaptive thresholding algorithm for the BTV estimation allows obtaining a robust and reliable method to be applied to a variety of different scanners, without scanner-specific individual calibration.

Correlation of [18F] FDG-PET/CT with dosimetry data: recurrence pattern after radiotherapy for head and neck carcinoma

“…Besides integration of different imaging and clinical data, PET/CT based contouring could also be improved. As shown in Brambilla’s study, radiation oncologists should probably move from visual PET interpretation to an established method for PET volume segmentation and reconstruction algorithms [ 12 ].…”

“…Only primary tumor and local recurrence was considered for MTV contouring, and neck nodes were included only when positive at PET pre . In this regard, ATA contouring method was previously developed and validated on pre-clinical data by Brambilla et al [ 8 , 12 ]. ATA is a standardized image segmentation tool using an objective function that generates a threshold based upon the characteristics of each tumor lesion and the tumor to background signal ratio thus the pixels are labelled as target (MTV) if their intensity is higher than the threshold, whereas those with a lower intensity are considered non-target).…”

The Spatial Relationship between Apparent Diffusion Coefficient and Standardized Uptake Value of 18F-Fluorodeoxyglucose Has a Crucial Influence on the Numeric Correlation of Both Parameters in PET/MRI of Lung Tumors

“…The PET data were evaluated by reader 1 using a commercially available workstation (SyngoVia, Software Version 3.0, Siemens Healthineers, Erlangen, Germany). The lesions were segmented semiautomatically using a dedicated 3D volume of interest (VOI) segmentation tool and an adaptive thresholding method as published by Brambilla et al [ 12 ]. With this approach, their SUV max and SUV mean values were recorded and, in addition, the metabolic tumor volume ( V PET ), the maximum diameter of the lesion in 3 dimensions ( D ), and the coordinates of the SUV max -voxel were measured.…”

Correlation of [18F] FDG-PET/CT with dosimetry data: recurrence pattern after radiotherapy for head and neck carcinoma

“…Only primary tumor and local recurrence was considered for BTV contouring, and neck nodes were included only when conglomerated with the primary tumor. In this regard, ATA contouring method was previously developed and validated on pre-clinical data by Brambilla et al 8,12 . ATA is a standardized image segmentation tool using an objective function that generates a threshold based upon the characteristics of each tumor lesion and the tumor to background signal ratio thus the pixels are labelled as target (BTV) if their intensity is higher than the threshold, whereas those with a lower intensity are considered non-target).…”