A study published in the December issue of Clinical Nuclear Medicine found that PET/CT with 18F-FDOPA is superior to both 18F-FLT and 18F-FDG for visualization of primary and recurrent low-grade gliomas.
In the study, 15 patients with newly diagnosed or previously treated low-grade gliomas (WHO grade I or II) including two patients in remission (control subjects) were subjected to 18F-FDOPA, 18F-FDG and 18F-FLT PET/CT studies on consecutive days.
Madhavi Tripathi, MD, and colleagues at the division of PET imaging molecular imaging and research center at the Institute of Nuclear Medicine and Allied Sciences in Delhi, India, analyzed the uptake of all the three tracers visually and quantified using standardized uptake values and tumor to normal (T/N) ratios.
According to the investigators, 18F-FDOPA was positive in all 13 cases of primary and recurrent low grade gliomas and negative in patients in remission, while tumor was positive only in seven of 13 cases with 18F-FDG and in four of 13 cases with 18F-FLT.
“Average tumor standardized uptake values for 18F-FLT (1.8) was lower than that of 18F-FDOPA (5.75) and 18F-FDG (8.5). T/N ratios for 18F-FDOPA (2.3) and 18F-FLT (1.8) were higher than 18F-FDG (1.03), providing good image contrast for tumor detection in positive cases," said Tripathi.
The investigators concluded that 18F-FDOPA scan is superior to both 18F-FLT and 18F-FDG for visualization of primary and recurrent low-grade gliomas and 18F-FLT should not be considered for evaluation of recurrent low-grade gliomas.