Two Decades of Brain Tumour Imaging with O-(2-[18F]fluoroethyl)-L-tyrosine PET: The Forschungszentrum Jülich Experience

Abstract

O-(2-[18F]fluoroethyl)-L-tyrosine (FET) is a widely used amino acid tracer for positron emission tomography (PET) imaging of brain tumours. This retrospective study and survey aimed to analyse our extensive database regarding the development of FET PET investigations, indications, and the referring physicians’ rating concerning the role of FET PET in the clinical decision-making process. Between 2006 and 2019, we performed 6534 FET PET scans on 3928 different patients against a backdrop of growing demand for FET PET. In 2019, indications for the use of FET PET were as follows: suspected recurrent glioma (46%), unclear brain lesions (20%), treatment monitoring (19%), and suspected recurrent brain metastasis (13%). The referring physicians were neurosurgeons (60%), neurologists (19%), radiation oncologists (11%), general oncologists (3%), and other physicians (7%). Most patients travelled 50 to 75 km, but 9% travelled more than 200 km. The role of FET PET in decision-making in clinical practice was evaluated by a questionnaire consisting of 30 questions, which was filled out by 23 referring physicians with long experience in FET PET. Fifty to seventy per cent rated FET PET as being important for different aspects of the assessment of newly diagnosed gliomas, including differential diagnosis, delineation of tumour extent for biopsy guidance, and treatment planning such as surgery or radiotherapy, 95% for the diagnosis of recurrent glioma, and 68% for the diagnosis of recurrent brain metastases. Approximately 50% of the referring physicians rated FET PET as necessary for treatment monitoring in patients with glioma or brain metastases. All referring physicians stated that the availability of FET PET is essential and that it should be approved for routine use. Although the present analysis is limited by the fact that only physicians who frequently referred patients for FET PET participated in the survey, the results confirm the high relevance of FET PET in the clinical diagnosis of brain tumours and support the need for its approval for routine use.

Hybrid18F-Fluoroethyltyrosine PET and MRI with Perfusion to Distinguish Disease Progression from Treatment-Related Change in Malignant Brain Tumors: The Quest to Beat the Toughest Cases

“…This study is also susceptible to referral bias, omitting cases in which a prior MRI exam sufficiently established a definitive diagnosis, as evidenced by the low diagnostic performance of contrast-enhanced MRI lesion volume change relative to other investigated parameters ( Table 3 ). However, this implicit focus on challenging case referrals is consistent with other reports in the literature and with the common clinical indications for 18 F-FET PET ( 43 ). Additionally, this study was limited in sample size for stratification by disease type.…”

Radiosynthesis and Analysis of (S)-4-(3-[18F]Fluoropropyl)-L-Glutamic Acid

“…Within oncological PET imaging, 18 F-labelled amino acids (AA) are important radiotracers for the detection of tumour proliferation [1]. Perhaps, the most notable is O-(2-[ 18 F]fluoroethyl)-L-tyrosine [2], although, more recently, 18 F-analogues of glutamine and glutamic acid have become radiotracers of considerable interest. Examples include [ 18 F]-(2S,4R)4-fluoroglutamine [3][4][5][6][7], [ 18 F](2S,4S)-4-(3fluoropropyl)glutamine [8], 4-[ 18 F]fluoroglutamic acid [9],…”

Delineation and agreement of FET PET biological volumes in glioblastoma: results of the nuclear medicine credentialing program from the prospective, multi-centre trial evaluating FET PET In Glioblastoma (FIG) study—TROG 18.06

“…Accurate tumour delineation and interpretation of FET PET are crucial for glioblastoma patient management, which includes assessment of newly diagnosed tumour for biopsy planning and surgical intervention, differential diagnosis at suspected progression, and treatment monitoring. The most frequent indication for FET PET scans being performed is at suspected tumour recurrence [ 35 ]. Although clinical evaluation primarily evaluates qualitative parameters and TBRs, the BTV also plays a role as a prognostic biomarker and for treatment response when comparing previous imaging timepoints [ 36 , 37 ].…”