Prospective Comparison of 68Ga-DOTA-IBA, 99mTc-MDP Scintigraphy, and Multidetector CT for Skeletal Metastases

Objective : This prospective study was to evaluate the diagnostic efficacy of ⁶⁸ Ga-labeled DOTA-ibandronic acid positron emission tomography/computed tomography ( ⁶⁸ Ga-DOTA-IBA PET/CT), ^99m Tc-labelled methylene diphosphonate( ^99m Tc-MDP) bone scintigraphy, and multidetector computed tomography (CT) in detecting bone metastases. Patients and Methods : This ongoing prospective trial, conducted between March 2022 and April 2024, enrolled 138 oncology patients (70 men and 68 women, aged 27 to 92 years). These individuals had either been diagnosed with or were under suspicion of having bone metastases. Each participant underwent ⁶⁸ Ga-DOTA-IBA PET/CT, ^99m Tc-MDP bone scintigraphy, and CT scans within one week. The resulting images were subsequently analyzed on an individual basis by seasoned radiologists and nuclear medicine specialists. Result: A total of 1628 lesions were identified as malignant, with 1521 (93.4%) detected using ⁶⁸ Ga-DOTA-IBA PET/CT, with 1245 lesions (76.5%) identified through ^99m Tc-MDP bone scintigraphy, and with 1350 lesions (82.9%) revealed by CT scanning. On an individual patient basis, the detection rate of bone metastases was 98.6% (136/138) for ⁶⁸ Ga-DOTA-IBA PET/CT, 97.8% (135/138) for ^99m Tc-MDP bone scintigraphy, and 95.7% (132/138) for CT. The maximum standardized uptake value (SUVmax) for malignant lesions was markedly higher than that observed in benign lesions (p<0.001). The area under the curve (AUC) for SUVmax, when diagnosing bone metastases with ⁶⁸ Ga-DOTA-IBA PET/CT, was 0.969, utilizing a threshold of 4.6 to differentiate between benign and malignant lesions. Conclusion: ⁶⁸ Ga-DOTA-IBA PET/CT has a higher detection rate for skeletal metastases than conventional bone scintigraphy or CT. The detection of occult bone metastases with ⁶⁸ Ga-DOTA-IBA PET/CT is crucial for precise tumor staging and the formulation of therapeutic strategies.