Head-to-Head Comparison of [Ga]Ga-NOTA-RM26 and [F]FDG PET/CT in Patients with Gastrointestinal Stromal Tumors: A Prospective Study.

Gastrointestinal stromal tumors (GISTs) are the most common stromal tumors in the gastrointestinal tract. This study was designed to evaluate a gastrin-releasing peptide receptor antagonist PET tracer, [Ga]Ga-NOTA-RM26, and compare it with [F]FDG PET/CT in the assessment of patients with GISTs. With institutional review board approval and informed consent, 30 patients with suspected or proven GISTs based on abdominal CT or gastroscopy were recruited. All patients underwent [Ga]Ga-NOTA-RM26 and [F]FDG PET/CT scans. Pathology and other patient information were collected. No radiopharmaceutical-related adverse events were observed in the patients. In total, 18 lesions in 16 patients were diagnosed as GIST, 3 patients were diagnosed with schwannoma, and 4 patients were diagnosed with leiomyoma. In 18 GISTs, the mean SUV of [Ga]Ga-NOTA-RM26 PET was significantly higher than that of [F]FDG PET (17.07 ± 19.57 vs. 2.28 ± 1.65; < 0.01), and [Ga]Ga-NOTA-RM26 PET/CT had a higher tumor detection rate than did [F]FDG PET/CT (88.9% vs. 50%; < 0.01). The uptake of [Ga]Ga-NOTA-RM26 in GISTs was significantly higher than that in 2 other benign tumors (leiomyoma or schwannoma) (17.07 ± 19.57 vs. 4.23 ± 1.77; = 0.014). With the SUV cutoff value of 6.0, the sensitivity of Ga-NOTA-RM26 PET/CT in diagnosing GISTs is 72% and the specificity is 85.7%. Compared with [F]FDG PET/CT, [Ga]Ga-NOTA-RM26 PET/CT is a promising and effective imaging modality for the detection of GISTs.