Abstract
Background: Positron emission tomography-computed tomography (PET-CT) can be used to detect and stage metastatic lymph nodes in intermediate to high-risk prostate cancer. Improvements to hardware, such as digital technology, and to software, such as reconstruction algorithms, have recently been made. We compared the capability of detecting regional lymph node metastases using conventional and digital silicon photomultiplier (SiPM)-based PET-CT technology for [18F]-fluorocholine (FCH). Extended pelvic lymph node dissection (ePLND) histopathology was used as the reference method.Methods: Retrospectively, a consecutive series of patients with prostate cancer who had undergone staging with FCH PET-CT before ePLND were included. Images were obtained with either a conventional or a SiPM-based PET-CT and compared. FCH uptake in pelvic lymph nodes beyond the uptake in the mediastinal blood pool was considered to be abnormal.Results: One hundred eighty patients with intermediate or high-risk prostate cancer were examined using a conventional Philips Gemini PET-CT (n = 93) between 2015 and 2017 or a digital GE Discovery MI PET-CT (n = 87) from 2017 to 2018. Images that were obtained using the Philips Gemini PET-CT system showed 19 patients (20%) with suspected lymph node metastases compared with 40 patients (46%) using the GE Discovery MI PET-CT. Sensitivity, specificity, and positive and negative predictive value (PPV and NPV) were 0.30, 0.84, 0.47, and 0.72, respectively, for the Philips Gemini and 0.60, 0.58, 0.30, and 0.83, respectively for GE Discovery MI. Area under the curve (AUC) in a receiver operating characteristics (ROC) analysis was similar between the two PET-CT systems (0.58 and 0.58, P = 0.8).Conclusions: A marked difference in sensitivity and specificity was found for the different PET-CT systems, although similar overall diagnostic performance. This is probably due to differences in both hard- and software, including reconstruction algorithms, and should be considered when new technology is introduced.
[18F]fluoroethylcholine-PET/CT imaging for radiation treatment planning of recurrent and primary prostate cancer with dose escalation to PET/CT-positive lymph nodes
