TY - JOUR T1 - A Comparative study between [<sup>18</sup>F]- FDG and [<sup>18</sup>F]-fluoro-ethyl-L-tyrosine PET-CT in diagnosing recurrent brain tumours and grading of tumours using FET preoperatively. JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1689 LP - 1689 VL - 59 IS - supplement 1 AU - Hitesh Aggarwal AU - RAJNISH SHARMA AU - MARIA DSOUZA AU - Sanjiv Saw AU - Santosh Pandey AU - Yachna Solanki AU - Tarakant Kumar Y1 - 2018/05/01 UR - http://jnm.snmjournals.org/content/59/supplement_1/1689.abstract N2 - 1689Objectives: Rationale - 18- fluoro- ethyl- tyrosine (FET) PET-CT is a well established technique for evaluation of tumour for diagnosis and treatment planning in neuro- oncology. FET reflects amino acid transfer and has been shown to be more sensitive than MRI in stereotactic biopsy planning. This study compared FET PET-CT and Fluorodeoxyglucose (FDG) PET-CT in detection of various brain tumours and brain metastasis. An attempt has been made to diagnose tumour grade using FET PET-CT through dynamic scanning. Methodology - 25 subjects of brain tumour treated by surgery, chemo-therapy and radiotherapy were subjected to FDG &amp; FET scan. The lesions were analysed semi-quantitatively using tumour to normal contra-lateral uptake ratio. Dynamic scan was taken for FET PET-CT and an uptake time graph was plotted for the lesions reported as positive on the scan. Diagnosis was confirmed by surgery, stereotactic biopsy, clinical follow up, MRI or CT scan. Key Results - Tumour recurrence was found in only 5 out of 25 patients on FDG scan while FET PET was able to detect recurrence in 20 out of 25 patients. Five patients in which FDG scan was positive were found to have peak tumour uptake at 15 minutes in FET scan and were found to be high grade gliomas in post operative biopsy. The other FET positive cases showed peak tracer uptake at 30 to 40 minutes and were found to be low grade gliomas. No false positive cases were reported in the study. On semi quantitative analysis mean Target /Non- Target (T/NT) ratio was found to be 3.5 +/- 0.94 in lesions positive for tumour recurrence in FET scan . While in FDG scan T/NT ratio was found to be 2.05 +-1.04 in lesions positive for tumour recurrence. Research Highlights - The study highlights that FET PET-CT is superior to FDG PET-CT in detecting recurrent brain tumours . Time of peak uptake value is usefull in determining grade of gliomas non- invasively. Therefore, amino acids like (18)F-FET are the preferred PET tracers for the clinical management of brain tumors. Bibliography- Pöpperl G, Gotz C, Rachinger W, Gildehaus FJ, Tonn JC, Tatsch K. Value of O-(2-[18F]fluoroethyl)-L-tyrosine PET for the diagnosis of recurrent glioma. Eur J Nucl Mol Imaging. 2004;31:1464-1470.Objectives: Pauleit D, Floeth F, Hamacher K, et al. O-(2-[18F]fluoroethyl)-L-tyrosine PET combined with magnetic resonance imaging improves the diagnostic assessment of cerebral gliomas. Brain. 2005;128:678-687.Objectives: Floeth FW, Pauleit D, Wittsack HJ, et al. Multimodal metabolic imaging of cerebral gliomas: positron emission tomography with [18F]fluoroethyl-L-tyrosine and magnetic resonance spectroscopy. J Neurosurg. 2005; 102: 318-327.Objectives: Weckesser M, Langen KJ, Rickert CH, et al. O-(2-[18F]fluoroethyl)-L-tyrosine PET in the clinical evaluation of primary brain tumors. Eur J Nucl Med Mol Imaging.2005;32:422-429.Pauleit D1, Stoffels G, Bachofner A, Floeth FW, Sabel M, Herzog H, Tellmann L, Jansen P, Reifenberger G, Hamacher K, Coenen HH, Langen KJ. Comparison of (18)F-FET and (18)F-FDG PET in brain tumors. Nucl Med Biol. 2009 Oct;36(7):779-87. Kathy Mahdoubi. FET PET points to additional glioma activity compared with MRI. J Nucl Med February 2006 vol. 47 no. 2 256-261. ER -