Elsevier

PET Clinics

Volume 9, Issue 3, July 2014, Pages 345-349
PET Clinics

PET/MRI Radiotracer Beyond 18F-FDG

https://doi.org/10.1016/j.cpet.2014.03.010Get rights and content

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Key points

  • The recent development and introduction of new hybrid imaging devices combining positron emission tomography (PET) technology with magnetic resonance imaging (MRI) opens up new perspectives in clinical molecular imaging.

  • Combining MRI and fluorine-18 choline PET would theoretically produce valuable clinical data in a single imaging session, which can be used for staging, prognosis, and assessment of treatment response.

  • Fluorine-18–sodium fluoride (18F-NaF) is a highly sensitive PET tracer used as

Fluorine-18 choline/carbon-11 choline

Choline is an amino acid needed for the synthesis of phospholipids in cell membranes, methyl metabolism, cholinergic neurotransmission, transmembrane signaling, and lipid-cholesterol transport and metabolism. The most important metabolic process for the tumor detection is the aberrant phospholipid metabolism (upregulation of choline kinase), which results in an increased mitotic signaling and plasma membrane biosynthesis.1 Choline is transported inside the cell, phosphorylated, and metabolized

Gallium 68–tetraazacyclododecane tetraacetic acid–octreotate compounds

Gallium 68–tetraazacyclododecane tetraacetic acid–octreotate (68Ga-DOTATATE) is an amide of the acid 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), which binds a derivative of octreotide (Tyr)-octreotate.6 Similar molecules are [68Ga]-DOTA-D Phe1-Tyr3-Octreotide (68Ga-DOTATOC) (DOTA-D-phel-Tyr3-octreotide) and DOTANOC (DOTA-1-NaI-octreotide). The use of these radiotracers has recently increased because of their convenient preparation using a germanium-68/gallium-68 (68Ge/68Ga)

Fluorine-18–sodium fluoride

Fluorine-18–sodium fluoride (18F-NaF) is a highly sensitive PET tracer used for detecting skeletal osteoblastic abnormalities.11, 12 Fluorine-18–sodium fluoride is an analog of the hydroxyl ion in the bone matrix and is rapidly exchanged with high initial extraction fraction in the hydroxyapatite crystals. The uptake of 18F-NaF correlates with blood flow and bone remodeling; therefore, it is not tumor-specific and can be a viable option for studying different benign skeletal processes.13

Fluorine-18–labeled dihydroxyphenylalanine

Dihydroxyphenylalanine (DOPA) is a neutral amino acid analog to the dopamine precursor 3,4-dihydroxy-l-phenylalanine (l-DOPA). It is internalized by the amino acid transport system for large neutral amino acids and enters the catecholamine metabolic pathway of endogenous l-DOPA in the brain and peripheral tissue.17 It was first assembled with 18F for the study of Parkinson disease. Its use has recently been expanded to include imaging of some neuroendocrine tumors, primary brain neoplasias, and

Fluorine-18–flutemetamol

Flutemetamol (2-[4-(methylamino)phenyl]-1,3-benzothiazol-6-ol) is a neutral analog of thioflavin T. Multiple studies have confirmed the capability of this molecule to cross the blood–brain barrier and to reversibly bind fibrillar β-amyloid in the brain.22 Flutemetamol was initially labeled with an 11C isotope, limiting its availability because of the 20-minute half-life of the 11C. 18-Florbetapir is a similar agent, which tracks the amyloid deposits and has shown some promise in assessing the

Fluorine-18–fluoromisonidazole

Fluorine-18–fluoromisonidazole (F-MISO) is one of the most commonly used radiotracer for hypoxia. Misonidazole is a nitroimidazole and thus, after passive diffusion into the cell, is reduced with nitro anion radicals. In the presence of oxygen, the last reaction is reversible and the molecule can leave the cell, but in absence of oxygen, misonidazole is reduced and remains trapped in the cell.

Since the early 1980s, Misonidazole has been known to be not only a useful tracer for identifying

Cardiovascular molecular imaging applications

Positron emission tomography allows an accurate assessment of myocardial perfusion and coronary artery disease (CAD), and remains a valuable tool for the assessing myocardial viability in patients with severe left ventricular dysfunction. Positron emission tomography/computed tomography imaging allows a comprehensive evaluation of the functional and morphologic severity of CAD. Combining the ability of MRI to produce high-resolution anatomic images and the high sensitivity of PET for detecting

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