Molecular imaging: what can be used today

Abstract

Biochemical cellular targets and more general metabolic processes in cancer cells can be visualised. Extensive data are available on molecular imaging in preclinical models. However, innovative tracers move slowly to the clinic. This review provides information on the currently available methods of metabolic imaging, especially using PET in humans. The uptake mechanisms of tracer methods and a brief discussion of the more 'molecular' targeted methods are presented. The main focus is on the different classes of tracers and their application in various types of cancer within each class of tracers, based on the current literature and our own experience. Studies with [ 18 F]FDG (energy metabolism), radiolabelled amino acids (protein metabolism), [ 18 F]FLT (DNA metabolism), [ 11 C]choline (cell membrane metabolism) as general metabolic tracer methods and [ 18 F]DOPA (biogenic amine metabolism) as a more specific tracer method are discussed. As an example, molecular imaging methods that target the HER2 receptor and somatostatin receptor are described.

Clinical role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in post-operative follow up of gastric cancer: Initial results

“…Modern cancer care is critically dependent on imaging technologies, which are used to detect early tumors and guide their therapy or surgery [17,18] . Molecular imaging technologies provide information about the functional or metabolic characteristics of malignancies, tumor stage and therapeutical response, and tumor recurrence; whereas conventional imaging technologies predominantly assess anatomical or morphologic features of the tumor including its size, density, shape, etc [19,20] . There are now various indications for 18 F-FDG PET and PET/CT imaging in gastrointestinal malignancies [21] .…”

Specific biomarkers of receptors, pathways of inhibition and targeted therapies: clinical applications

“…It has long been known that tumours contain large quantities of lactic acid, because they rely on anaerobic glycolysis for a major part of their energy consumption [21]. However, this is a relatively inefficient process, since anaerobic glycolysis generates only a limited amount of energy (adenosine triphosphate) per molecule of glucose.…”

“…This intracellular trapping, in combination with the relatively high resolution of PET cameras, leads to adequate detection properties of metabolically active tumours and metastases. glucose metabolism to assist in the evaluation of malignancy in patients with known or suspected abnormalities found by other testing modalities, or in patients with an existing diagnosis of cancer [21]. The European Organization for Research and Treatment of Cancer PET Group has established response assessment guidelines for PET [24].…”

Interrogating Tumor Metabolism and Tumor Microenvironments Using Molecular Positron Emission Tomography Imaging. Theranostic Approaches to Improve Therapeutics

“…Nuclear medicine approaches to cancer imaging can be divided into three main domains: 1) imaging metabolic processes, which is generally called "metabolic imaging"; 2) "functional imaging" that measures blood flow, oxygen consumption, and other functionalities (Gil-da-Costa et al, 2006); and 3) "molecular imaging" methods aimed at more specific biochemical targets (Jager et al, 2005).…”