Abstract
INTRODUCTION: 68Ga-DOTATATE PET imaging has emerged as a promising adjunct tool for evaluating meningiomas due to high affinity for the SSTR-2 receptor, which is highly expressed on meningiomas. A recent consensus paper recommends 68Ga-DOTATATE PET in conjunction with MRI for improved tumor localization, anatomical characterization, radiotherapy planning, and post-treatment assessment to help guide patient management decisions. This study aims to assess treatment response in meningioma patients by examining changes in maximum standardized uptake value (SUV) and normalized SUV ratios to evaluate their dynamics after radiotherapy. METHODS: Patients who underwent 68Ga-DOTATATE PET imaging before and after radiotherapy were retrospectively evaluated. ROIs were placed using Mirada XD3 software to measure maximum SUV for the lesion (SUV_max), pituitary gland (SUV_Pit), and superior sagittal sinus (SUV_SSS). Normalized uptake ratios were calculated as SUVR_SSS (lesion SUV_max/SUV_SSS) and SUVR_Pit (lesion SUV_max/SUV_Pit). Pre- and post-treatment PET data were analyzed using paired t-tests and Spearman’s correlation on IBM SPSS v29. RESULTS: We evaluated 19 patients (mean age 61.2 years; range 34–80; 15 females, 4 males) diagnosed with WHO Grade 1 (n=1), Grade 2 (n=14), and Grade 3 (n=1) meningiomas. No grading was available for 3 patients. Following radiotherapy, mean SUV_max decreased from 20.35 to 15.44 (−25.9%, p=0.0093). SUV_SSS increased from 1.62 to 1.80 (+14.2%, p=0.0082), while SUV_Pit showed no significant difference (14.16 vs. 13.99, p=0.8411). SUVR_SSS decreased from 12.27 to 8.47 (−33.1%, p=0.0018). SUVR_Pit showed no statistically significant difference, and no correlation was observed between baseline SUV_max and percent change (r=0.124, p=0.6131). CONCLUSIONS: Our study identified measurable changes in SUV_max, SUV_SSS, and normalized SUV ratios in post-radiotherapy meningiomas, supporting their potential as response assessment biomarkers. However, the small sample size limits broader conclusions, necessitating further investigation with a larger prospective cohort.