Evaluation of 99mTc‐L‐methionine brain SPECT for detection of recurrent brain tumor: a pilot study with radiological and pathological correlation

Abstract

Purpose: To evaluate technetium labeled l‐methionine for imaging recurrent brain tumors. Material and Methods: Brain SPECT with 99mTc‐l‐methionine was performed to evaluate tumor viability in 42 patients with primary brain tumor. Findings of SPECT were correlated with radiological and histopathological findings as reference. Results:99mTc‐l‐methionine showed localized increased uptake in 40 patients with tumor recurrence, whereas 2 patients with post‐radiation gliosis did not show tracer accumulation. A low differential uptake rate (DUR) 2.43±0.74 and methionine retention (MR) index 0.93±0.03 was seen in cases of post‐radiation gliosis. A high DUR (36.20±10.31) and MR index (4.87±2.37) was seen in cases of recurrent tumor. Mean DUR in high‐grade tumors (44.01±8.46) was significantly higher ( P<0.001) than in low‐grade tumors (30.42±7.38), and mean MR index in high‐grade tumors (7.03±2.05) was significantly higher than in low‐grade tumors (3.27±0.82) ( P<0.001). Conclusion:99mTc‐l‐methionine can be used as a SPECT tracer to differentiate tumor recurrence from post‐radiation gliosis.