Stomach and duodenum
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie in Bailey & Love's Short Practice of Surgery, 2018
Positron emission tomography (PET) is a functional imaging technique which relies on the uptake of a tracer in most cases by metabolically active tumour tissue. Fluorodeoxyglucose (FDG) is the most commonly used tracer. This tracer has a short half-life hence manufacture and use have to be carefully coordinated. To be of value, anatomical and functional information need to be linked, hence PET/CT is now used universally. It is increasingly being used in the preoperative staging of gastro-oesophageal cancer as it will demonstrate occult spread which renders the patient surgically incurable in up to 10% of patients who would otherwise have undergone major resections (Figure63.9). PET/CT may also be used to determine the response to neoadjuvant chemotherapy in oesophagogastric malignancies although this is the subject of ongoing studies.
Treatment planning
Jing Cai, Joe Y. Chang, Fang-Fang Yin in Principles and Practice of Image-Guided Radiation Therapy of Lung Cancer, 2017
18F-fluorodeoxyglucose (18F-FDG) is the most common tracer used in PET scanning. PET images are based on metabolic activity, not anatomy. PET is commonly used to distinguish suspicious lesions, more accurately define tumor volume and lymph node involvement, detect distant metastases, and aid in treatment planning [19–25]. Both CT and PET are part of the standard workup for all newly diagnosed cases of lung cancer (NCCN). While PET is considered a more accurate imaging modality in clinical staging of lung cancer, a combined PET/CT approach leads to an increased accuracy in the staging of lung cancer [26–28]. By using integrated PET/CT scanners, one can obtain information on abnormal uptake and anatomy since they share DICOM coordinates, as seen in Figure 4.6. In a study performed by Ciernik et al. using an integrated PET/CT scanner, 56% of the cases had significantly altered GTV contours based on the PET images [29]. In another 2003 study published in the New England Journal of Medicine, for two years of patients from a tertiary teaching institution in Switzerland diagnosed with NSCLC underwent integrated whole body PET-CT as part of their staging. The PET-CT provided additional information in 41% of patients, leading to improved staging accuracy [30]. However, when PET scans are performed separately from CT scans, image fusion becomes more challenging since the PET images are based on metabolic activity instead of anatomy.
Small Animal Imaging and Therapy
George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos in Handbook of Small Animal Imaging, 2018
Most of the commercially available pharmaceuticals are small molecules whose mechanism of action is typically based on direct interactions as an agonist or antagonist with the target tissue or cells. When labeled with radioactive metals, paramagnetic moieties, or optical molecules, small pharmaceutical compounds become powerful tools to assess the pathophysiology of the disease process, which allows not only the early detection of pathological processes but also the monitoring of the response to the therapeutic intervention. For example, a glucose analogue radiolabeled with fluorine-18 fluorodeoxyglucose is commonly used to measure tissue glucose consumption associated with enhanced metabolism. This phenomenon has been used in several PET imaging applications in neuroscience (activation of certain brain areas), cardiology (myocardial metabolism), and oncology (detection of primary tumors and metastases) (Rudd et al. 2002; Ogawa et al. 2004; Tawakol et al. 2006; Mullani et al. 2008).
Positive association between cerebral grey matter metabolism and dopamine D2/D3 receptor availability in healthy and schizophrenia subjects: An 18F-fluorodeoxyglucose and 18F-fallypride positron emission tomography study
Published in The World Journal of Biological Psychiatry, 2020
Serge A. Mitelman, Monte S. Buchsbaum, Bradley T. Christian, Brian M. Merrill, Bradley R. Buchsbaum, Jogeshwar Mukherjee, Douglas S. Lehrer
FDG images were normalised by dividing each voxel by mean values of the whole brain, masked with MNI brain and using slices above MNI z = −53 (see image alignment in a typical subject with schizophrenia in Figure 1). A restricted vertical range was chosen to minimise errors in the brain extraction routine at low slice levels. These relative 18F-fluorodeoxyglucose metabolic rates were used in all analyses. For analyses of 42 Brodmann areas, gyri, hippocampus, insula, and subcortical structures, FDG uptake and 18F-fallypride BPND values were obtained using AFNI regions of interest (Cox 1996). Subcortical structures included the amygdala, cerebellar subregions (tonsil, culmen, declive, tuber and pyramid of the vermis, dentate and fastigial nuclei), basal ganglia associated structures (head, body and tail of the caudate nucleus, putamen, lateral globus pallidus, medial globus pallidus, red nucleus, substantia nigra, claustrum), hypothalamus and mamillary bodies, thalamic nuclei (pulvinar, ventral anterior, lateral dorsal, ventral lateral, ventral posteromedial, lateral posterior, ventral posterolateral, mediodorsal as well as anterior and midline nuclear groups).
Factors affecting the dynamics and heterogeneity of the EPR effect: pathophysiological and pathoanatomic features, drug formulations and physicochemical factors
Published in Expert Opinion on Drug Delivery, 2022
Rayhanul Islam, Hiroshi Maeda, Jun Fang
Intracellular uptake of drugs released from nanocarriers is also a critical matter for producing the expected cytotoxicity. That is, selection of anticancer drugs with the property of rapid internalization is important for the design of nanomedicines. For example, the derivative THP had a 10- to 60-fold faster intracellular uptake compared with doxorubicin [95]. Thus, THP demonstrates far greater cytotoxicity than doxorubicin, even though both belong to the same anthracycline group of anticancer drugs, the only difference being one additional tetrapyranyl group in THP compared with doxorubicin [96,97]. Many transporter molecules in tumor cells such as the glucose/pyranose transporter are highly upregulated, which seems to be the mechanism related to the more rapid uptake of THP compared with doxorubicin [96,97]. This property is actually widely utilized in positron emission tomography for imaging solid tumors with 19F18-fluorodeoxyglucose, which is taken up much faster by tumor cells than normal cells.
Arginine-lowering enzymes against cancer: a technocommercial analysis through patent landscape
Published in Expert Opinion on Therapeutic Patents, 2018
Rakhi Dhankhar, Pooja Gulati, Sanjay Kumar, Rajeev Kumar Kapoor
Cancer treatment is undergoing a renaissance with the expectation that the cure lies within the tumor. The rapid growth of science and technology has ameliorated our understanding of cancer metabolism and its differences with normal cells. This difference in the metabolism has been harnessed for screening, diagnosis, and treatment of cancer [1]. For example, the knowledge of Warburg effect (high rate of aerobic glycolysis in tumor cells) is utilized for the development of 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG-PET), a powerful imaging tool for the detection of various cancers [2]. The intensive growth of tumor cells elicits elevated nutrient requirements as compared to normal cells. Thus, the cancerous cells become auxotrophic for certain nutrients and rely upon the exogenous supply of these nutrients. Creating a metabolic and nutritional stress in cancerous cells is considered as a novel strategy in cancer treatment. Amino acid deprivation is one such targeted therapy which is characterized by the supply of exogenous enzymes which degrade the amino acids. Depletion of amino acids results in the unbalanced growth of auxotrophic tumor cells, and eventually their apoptosis. The normal cells become quiescent by entering in G0/G1 cell cycle arrest and regain normal proliferation later by synthesizing the amino acid by their usual machinery [3,4]. Thus, these enzymes affect only the auxotrophic cancerous cells, while the normal cells remain unaffected.
Related Knowledge Centers
- Glucose
- Glucose Uptake
- Positron Emission Tomography
- Radionuclide
- Metabolism
- Radiopharmaceutical
- Radioactive Tracer
- Medical Imaging
- Structural Analog
- Fluorine-18