Evaluation of the prostate cancer and its metastases in the [68Ga]Ga-PSMA PET/CT images: deep learning method vs. conventional PET/CT processing

Purpose This study demonstrates the feasibility and benefits of using a deep learning-based approach for attenuation correction in [Ga-68]Ga-PSMA PET scans. Methods A dataset of 700 prostate cancer patients (mean age: 67.6 +/- 5.9 years, range: 45-85 years) who underwent [Ga-68]Ga-PSMA PET/computed tomography was collected. A deep learning model was trained to perform attenuation correction on these images. Quantitative accuracy was assessed using clinical data from 92 patients, comparing the deep learning-based attenuation correction (DLAC) to computed tomography-based PET attenuation correction (PET-CTAC) using mean error, mean absolute error, and root mean square error based on standard uptake value. Clinical evaluation was conducted by three specialists who performed a blinded assessment of lesion detectability and overall image quality in a subset of 50 subjects, comparing DLAC and PET-CTAC images. Results The DLAC model yielded mean error, mean absolute error, and root mean square error values of -0.007 +/- 0.032, 0.08 +/- 0.033, and 0.252 +/- 125 standard uptake value, respectively. Regarding lesion detection and image quality, DLAC showed superior performance in 16 of the 50 cases, while in 56% of the cases, the images generated by DLAC and PET-CTAC were found to have closely comparable quality and lesion detectability. Conclusion This study highlights significant improvements in image quality and lesion detection capabilities through the integration of DLAC in [Ga-68]Ga-PSMA PET imaging. This innovative approach not only addresses challenges such as bladder radioactivity but also represents a promising method to minimize patient radiation exposure by integrating low-dose computed tomography and DLAC, ultimately improving diagnostic accuracy and patient outcomes.