Comparison of Ga-68 PSMA positron emission tomography/computerized tomography with Tc-99m MDP bone scan in prostate cancer patients

Background/aim: The aim of our study was to compare Tc-99m MDP bone scan and Ga-68 PSMA PET/CT in terms of detection of bone metastasis in prostate cancer patients. Materials and methods: A total of 28 prostate cancer patients with bone scan and PSMA PET/CT performed within 90 days were retrospectively included in our analysis. All bone lesions were scored as negative (score-0), positive (score-1), or suspicious (score-2) for metastasis by two experienced nuclear medicine physicians. Both patient-based and region-based analyses were made for all osseous lesions.
Results: On per-patient analysis; sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.7%, 52.9%, 50%, 75%, and 60.7%, respectively, for bone scan and 90.9%, 100%, 100%, 94.4%, and 96.4%, respectively, for PSMA PET/CT. On per-region analysis; sensitivity, specificity, PPV, NPV, and accuracy were 76.2%, 80.9%, 57.1%, 91.1%, and 79.8%, respectively, for bone scan and 85.7%, 100%, 100%, 95.5%, and 95.4%, respectively, for PSMA PET/CT.
Conclusion: Ga-68 PSMA PET/CT has higher sensitivity, specificity, and accuracy compared to bone scan in terms of bone metastasis detection in prostate cancer patients. Therefore, it might be the modality of choice for patients with suspicion for metastatic disease, despite negative bone scan and conventional imaging results