PURPOSE: PET-guided @entity5 tracking is a novel concept of biologically targeted image guidance for radiotherapy. A @entity5 tracking algorithm based on list-mode PET data has been developed and previously tested on dynamic phantom data. In this study, we investigate if @entity5 tracking is clinically feasible by applying the method to @entity2 @entity1 PET data. METHODS: PET-guided @entity5 tracking estimates the target position of a segmented volume in PET images reconstructed continuously from accumulated coincidence events correlated with external respiratory motion, simulating real-time applications, i.e., only data up to the current time point is used to estimate the target position. A target volume is segmented with a 50% threshold, consistently, of the maximum intensity in the predetermined volume of interest. Through this algorithm, the PET-estimated trajectories are quantified from four @entity2 @entity1 who have distinct @entity5 location and size. The accuracy of the PET-estimated trajectories is evaluated by comparing to external respiratory motion because the ground-truth of @entity5 motion is not known in @entity1 ; however, previous phantom studies demonstrated sub-2mm accuracy using clinically derived 3D @entity5 motion. RESULTS: The overall similarity of motion patterns between the PET-estimated trajectories and the external respiratory traces implies that the PET-guided tracking algorithm can provide an acceptable level of targeting accuracy. However, there are variations in the tracking accuracy between @entity5 due to the quality of the segmentation which depends on target-to-background ratio, @entity5 location and size. CONCLUSION: For the first time, a @entity5 tracking algorithm has been applied to @entity2 @entity1 PET data, demonstrating clinical feasibility of real-time @entity5 tracking for integrated PET-linacs. The target-to-background ratio is a significant factor determining accuracy: screening during treatment planning would enable appropriate @entity1 selection for PET-guided @entity5 tracking in radiotherapy.

WE-G-BRF-06: Positron Emission Tomography (PET)-Guided Dynamic Lung Tumor Tracking for Cancer Radiotherapy: First XXXX Simulations.

@entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'dynamic tumor', 'tumors'] @entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung cancer']
@entity1 :: (9606,Species) :: ['Patient']
