TU-F-12A-02: Quantitative Characterization of Normal Bone Marrow Proliferative Activity with FLT PET/CT

Abstract

Purpose: [F-18]FLT PET is a tool for assessing health of bone marrow by evaluating its proliferative activity. This study establishes a baseline quantitative characterization of healthy marrow proliferation to aid in diagnosis of hematological disease. Methods: 31 patients (20 male, 11 female, 41–76 years) being treated for solid cancers with no history of hematological disease, osseous metastatic disease, or radiation therapy received pre-treatment FLT PET/CT scans. Total bone marrow was isolated from whole body FLT PET images by manually removing organs and applying a standardize uptake value (SUV) threshold of 1.0. Because adult marrow is concentrated in the axial skeleton, quantitative total bone marrow analysis (QTBMA) was used to isolate marrow in the lumbar spine, thoracic spine, sacrum, and pelvis for analysis. SUV mean , SUV max , and SUV CV were used to quantify bone marrow proliferation. Correlations were explored between SUV and patient characteristics including age, weight, height, and BMI using the Spearman coefficient (ρ). Results: The population-averaged whole-skeleton SUV mean , SUV max , and SUV CV were 3.0±0.6, 18.4±5.7, and 0.6±0.1, respectively. Uptake values in the axial skeleton were similar to the whole-skeleton demonstrated by SUV mean in the thoracic spine (3.6±0.6), lumbar spine (3.3±0.5), sacrum (3.0±0.6), and pelvis regions (2.8±0.5). Whole-skeleton SUV max correlated with patient weight (ρ=0.47, p<0.01) and BMI (ρ=0.60, p<0.01), suggesting marrow activity is related to the body's burden. SUV measures in the thoracic spine, lumbar spine, sacrum, and pelvis were negatively correlated with age (ρ:−0.41 to −0.46, p≤0.02). These negative correlations reflect the fact that active marrow in the adult skeleton is localized in the axial skeleton and decreases with age. Conclusions: Normal bone marrow characterizations were determined using FLT PET. These results provide a baseline characterization against which proliferative activity of abnormal marrow can be compared.