The performance of 68Ga-DOTA-IBA PET/CT for detecting bone metastases compared with 99mTc-MDP bone scintigraphy

This study aimed to evaluate the diagnostic efficacy of 68Ga-labeled DOTA-ibandronic acid positron emission tomography/computed tomography (68Ga-DOTA-IBA PET/CT) and 99mTc-labelled methylene diphosphonate (99mTc-MDP) bone scintigraphy (BS) in detecting bone metastases. Patients who underwent both 99mTc-MDP bone scintigraphy and ⁶⁸Ga-DOTA-IBA PET/CT within a one-week interval between March 2022 and April 2024 were retrospectively enrolled in this study. A total of 133 patients (67 males and 66 females; age: 59.98 ± 12.58) were included. The resulting images were subsequently analyzed by seasoned nuclear medicine specialists. Diagnostic efficacy was assessed based on the detection rates of bone metastatic lesions by the two imaging modalities. The maximum standardized uptake values (SUVmax) of metastatic and benign bone lesions identified on ⁶⁸Ga-DOTA-IBA PET/CT were recorded to evaluate the diagnostic performance of ⁶⁸Ga-DOTA-IBA in differentiating malignant from benign bone lesions. A total of 1453 lesions were identified as bone metastases, with 1423 (97.9%) detected using 68Ga-DOTA-IBA PET/CT, and with 1208 lesions (83.1%) identified through optional SPECT-assisted 99mTc-MDP bone scintigraphy (p < 0.001). At the individual patient level, the detection rates of bone metastases using ⁶⁸Ga-DOTA-IBA PET/CT and SPECT-assisted 99mTc-MDP bone scintigraphy were both 132 out of 133 (99.2%), with no statistically significant difference observed. The SUVmax for malignant lesions was markedly higher than that observed in benign lesions (7.18(5.18 ~ 10.59) vs. 2.6(2.0 ~ 3.3), p < 0.001). The area under the curve (AUC) for SUVmax when diagnosing bone metastases with 68Ga-DOTA-IBA PET/CT was 0.958, utilizing a threshold of 4.0 to differentiate between benign and malignant lesions. 68Ga-DOTA-IBA PET/CT has a higher detection rate for skeletal metastases than SPECT-assisted 99mTc-MDP bone scintigraphy. Furthermore, ⁶⁸Ga-DOTA-IBA PET/CT has demonstrated a strong ability to differentiate between benign and malignant bone lesions.