According to E.A. Zerhouni, MD, former director of the National Institutes of Health has described molecular imaging as having “the potential to define itself as a core interdisciplinary science for extracting spatially and temporally resolved biological information at all physical scales from Angstroms to microns to centimeters in intact biological systems.” (Eugene P. Pendergrass New Horizons Lecture, Radiological Society of North America meeting, 2007)1. Molecular imaging aims at developing imaging instruments, imaging probes, assays, and quantification methods. Imaging can be done using magnetic resonance imaging (MRI), X-ray computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and optical (bioluminescence and fluorescence imaging)etc. The process of imaging can be elucidated as below:
The use of “labels” in imaging has many disadvantages including2, 3, 4, 5:
• Labeling produces undesirable and unanticipated interactions which compromise imaging data and lead to false conclusions.
• In case of cell based labeling assays the use of genetically modified cell lines alters cellular behavior.
• The use of contrast-enhancing labels, or fluorescent dyes damage the cells or interfere with their function.
• Labeling leads to modification of molecule of interest which causes changes in the properties of the specific biomolecule under study.
• Labeling strategies have synthetic challenges, multiple label issues and may exhibit interference with the binding site under study.
• The added fluorophores themselves are subject to photobleaching, limiting imaging time.
Label free detection/imaging techniques unlike label-based detection methods, avoid any tagging of the query...
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...ion with endoscopy.”6
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1. Cited in J Nucl MED; 49:25N-26N, 2008
2. Amy Swinderman Label-free: The way to be? 2011 http://www.ddnnews.com 3. Dr.John Comley, Progress in the Implementation of Label-Free Detection,
Drug Discovery, World Summer2008, http://www.ddw-online.com
4. Ray, S., Mehta, G., Srivastava, S. Label-free detection techniques for protein microarrays: Prospects, merits and challenges. Proteomics 2010, 10, 731-748
5. Freudiger, C.W. et al. Label-free biomedical imaging with high sensitivity by stimulated Raman scattering microscopy.
Science 322, 1857–1861 (2008), and (116, Vol.6 no.2, 2009, nature
Methods- imaging goes label-free).
6. Andrew Downes and Alistair Elfick, Sensors 2010, 10, 1871-1889; doi: 10.3390/s100301871, Raman Spectroscopy and Related Techniques in Biomedicine.
Zhang X., Tang H., Ye C. and Liu M. (2006). Structure-based drug design: NMR-based approach for ligand-protein interactions. Drug Discovery Today: Technologies. 3 (3), pp. 241-245.
During this time, it could only be used in a lab with semi-intense supervision. Now, fast forward a few decades and there are D.I.Y. at home kits. The process of Electrophoresis starts with an electric current being run through a gel containing the molecules of interest. The molecules will then travel through the gel in different directions and speeds, based on their size and charge, allowing them to be separated from each other. Dyes, fluorescent tags, and radioactive labels can all enable the molecules on the gel to be seen after they have been separated. Because of these identification markers, they appear as a band across the top of the gel. Electrophoresis can be used for many different things. It is used to identify and study DNA or DNA fragments, and helps us to better understand the molecular components of both living and deceased organisms. Electrophoresis can also be used to test for genes related to specific diseases and life altering diagnoses such as Multiple Sclerosis, Down’s Syndrome, kidney disease, and some types of cancer. Electrophoresis also plays a major role in the testing of antibiotics. It can be used to determine the purity and concentration of one specific type of antibiotic or several general antibiotics at a time. Electrophoresis is also extremely useful in the creation and testing of
Sequential single-source, multi-scan imaging is our simplest and oldest form of spectral imaging. An example of this method is to, “…simply acquire two scans-one at a low kVp and one at a high kVp setting.”(Steidley 2008). A benefit to this method is it requires nothing other than a standard CT scanner, giving no added cost to the facility. As always there are disadvantages with everything, we find quite a significant one with this method. Lentz states, “…it presents significa...
The description of PET scans in detail requires the understanding of the radioactive substance injected into the subject. First, a small amount of a biochemical substance is tagged with a positron-emitting radioisotope. A positron is an “anti-electron.” Positrons are given off during the decay of the nuclei of the radioisotope. When the positron emitted collides with an electron in the tissue of the subject, both the positron and the electron are annihilated. When this happens, the collision produces two gamma rays having the same energy (511 KeV), but going in opposite directions.
Sophisticated methods of testing are now being applied to human cells in petri dishes. Human volunteers are also being used and micro-dose with samples so small that they do not cause adverse reactions. The argument exists that these alternative testing methods are not only more cost effective but also more relevant because they are conducted using human cells and specimens; a method that isn’t hindered by species differences. In addition, computer generated models are being used to produce virtual reconstructions in order to test toxicity.
...tance, which creates contrast, and having a Magnetic Resonance Imaging scan, Computed Tomography (CT) scan, or a fluoroscopic X-ray.
3. Corey, E. J., Barbara Czako, and Laszlo Kurti. Molecules and medicine. New Jersey: John
When labeling food, it is critical to do it in a way that everybody can understand the actual content of food. Therefore, people will be able to choose the healthiest option.
Nuclear medicine has been used for more than 5 decades and has been very successful in diagnosing and treating a variety of diseases including brain tumors and many types of cancers. Molecular imaging is used in conjunction with nuclear medicine to provide images of the inside of your body on a molecular and cellular level, so that a diagnosis can be made as early as possible.
...blic knowledge. It will enable consumers to make conscious decisions on the food they are serving to themselves and their families. Using labels that include scientific names of additives, but no additional information is confusing to consumers. Additives like BVO or GMO’s can have the potential for health problems for some individuals. If the FDA required proper labeling of these ingredients, people could make the choice themselves. It is misleading to not include any ingredient in a product.
2). As a result, this scientific experiment changed the relationship of humankind and nature by foreseeing the modification of DNA of bacteria, yeast, plants, and animals to discover new medicines and to provide solutions for inherited diseases (Le Vine, 1999, p. 2).
Two major examples of phenomena used to image in the cancer field are the positron emission tomography (PET) and the single photon emission computed tomography (SPECT). The way that the “PET” works is that it creates computerized images of chemical changes, such as sugar in the metabolism, that take place in tissue. The radioactive sugar can help in the search to locating a tumor in a person’s body. Due to the reason that cancer cells take up or absorb sugar more avidly than other tissues in the body this is how the tomography is able to appear. If a tumor is present, the radioactive sugar will accumulate in the tumor. A computer translates this information into the images that are interpreted by a radiol...
d) Beyer T, Freudenberg L, Townsend D, Czernin J (2010). The future of hybrid imaging—part 1: Hybrid imaging technologies and SPECT/CT. Insights Into Imaging: 1-9. [PMC free article]. URL http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3288981/
Disadvantages of using antibody are that the binding capacity is strongly dependent on assay conditions such as pH level and temperature and this assay’s interaction between the antigen...
...created by injecting cancer cells into mice—can now be produced using DNA that’s made in a laboratory or taken from human cells.