False-Positive Findings on Bone Scintigraphy After MRI-Guided Stereotactic Ablative Radiotherapy for Osseous Oligometastasis

Abstract

Positron emission tomography/computed tomography (PET/CT) with ligands of the prostate-specific membrane antigen (PSMA) has been shown to be useful for initial staging of prostate cancer, assessment of biochemical recurrence, and detection of distant metastasis [1, 2]. For the detection of bone metastasis, PSMA PET was reported to have better sensitivity and specificity than bone scintigraphy [3]. Due to the high diagnostic accuracy for bone metastases, PSMA PET/CT plays an important role in the treatment of oligometastatic bone disease [4]. However, it is not known well whether PSMA PET can accurately diagnose the recurrence after radiation therapy for bone metastasis. Here, we report a case of oligometastatic prostate cancer who developed marginal recurrence of bone metastases previously treated with radical radiation therapy, which could not be detected by bone scintigraphy or bone single photon emission computed tomography/computed tomography (SPECT/CT) but could be diagnosed by 68Ga-PSMA PET/CT.