to their ionic charge, cannot exit from the cell. This results in intense radiolabeling of tissues with high glucose uptake, such as the normal brain, liver, kidneys, and most cancers, which have a higher glucose uptake than most normal tissue due to the Warburg effect. As a result, FDG-PET can be used for diagnosis, staging, and monitoring treatment of cancers, particularly in Hodgkin lymphoma, non-Hodgkin lymphoma, and lung cancer. A 2020 review of research on the use of PET for Hodgkin lymphoma found evidence that negative findings in interim PET scans are linked to higher overall survival and progression-free survival; however, the certainty of the available evidence was moderate for survival, and very low for progression-free survival. A few other isotopes and radiotracers are slowly being introduced into oncology for specific purposes. For example, 11C-labelled metomidate (11C-metomidate) has been used to detect tumors of adrenocortical origin. Also, FDOPA PET/CT (or F-18-DOPA PET/CT) has proven to be a more sensitive alternative to finding and also localizing pheochromocytoma than the MIBG scan. Neuroimaging Neurology PET imaging with oxygen-15 indirectly measures blood flow to the brain. In this method, increased radioactivity signal indicates increased blood flow which is assumed to correlate with increased brain activity. Because of its 2-minute half-life, 15O must be piped directly from a medical cyclotron for such uses, which is difficult. PET imaging with 18F-FDG takes advantage of the fact that the brain is normally a rapid user of glucose. Standard 18F-FDG PET of the brain measures regional glucose use and can be used in neuropathological diagnosis. Brain pathologies such as Alzheimer's disease greatly decrease brain metabolism of both glucose and oxygen in tandem. Therefore 18F-FDG PET of the brain may also be used to successfully differentiate Alzheimer's disease from other dementing processes, and also to make early diagnoses of Alzheimer's disease. The advantage of 18F-FDG PET for these uses is its much wider availability. Some 18F based radioactive tracers used for Alzheimer's include florbetapir, flutemetamol, PiB and florbetaben, which are all used to detect amyloid-beta plaques (a potential biomarker for Alzheimer's) in the brain. PET imaging with FDG can also be used for localization of seizure focus. A seizure focus will appear as hypometabolic during an interictal scan. Several radiotracers (i.e. radioligands) have been developed for PET that are ligands for specific neuroreceptor subtypes such as [11C] raclopride, [18F] fallypride and [18F] desmethoxyfallypride for dopamine D2/D3 receptors, [11C]