Optimizing acquisition time and injected dose in ¹⁸F-FDG PET/CT imaging using deep learning: enhancing image protocol...

This study aims to evaluate the effectiveness of deep learning algorithms in simulating standard acquisition time images from shortened acquisition times in ¹⁸F-FDG PET/CT imaging, thereby optimizing both image quality and radiopharmaceutical use.

We evaluated 322 patients who underwent ¹⁸F-FDG PET/CT, simulating half-dose conditions and reconstructing images at acquisition times of 30 s, 45 s, 60 s, 75 s, and 90 s while maintaining identical bed positions and anatomical coverage. Images were reconstructed using a residual U-Net architecture with data augmentation to enhance training. Image quality was assessed using a 5-point Likert scale, inter-reader consistency with Cohen's kappa, and quantitative metrics (PSNR, SSIM, MAE, MSE, RMSE) to compare pre- and post-processing conditions, validating the model's effectiveness. Lesion detectability was specifically assessed by counting detectable lesions before and after processing, evaluated by two senior nuclear medicine physicians to ensure consistency. Statistical analyses employed Wilcoxon signed-rank tests and kappa statistics, considering p-values less than 0.05 as statistically significant.

Deep learning significantly improved image quality scores in the half-dose group from 3.45 ± 0.48 to 4.33 ± 0.55 and enhanced kappa values from 0.76 to 0.82 (p < 0.05). Quantitative metrics demonstrated marked improvements, with SSIM values rising from 0.75 to 0.87 and PSNR from 37.65 dB to 41.37 dB in half-dose scenarios. Similarly, in the 30s model, SSIM increased from 0.73 to 0.84 and PSNR from 35.38 dB to 40.15 dB. Lesion detectability in small lesions improved by up to 16.3% in shortened acquisition conditions, effectively enhancing the detection of critical pathological features.

The application of deep learning models in PET/CT imaging may improve scan efficiency and reduce radiopharmaceutical usage while maintaining image quality without apparent loss of diagnostic information. These findings support the potential of AI-enhanced imaging protocols to reduce patient radiation exposure and improve clinical workflow efficiency.