Misplaced Pages

#747252

76-449: EDTA Is widely used in industry. It also has applications in food preservation, medicine, cosmetics, water softening, in laboratories, and other fields. EDTA is mainly used to sequester (bind or confine) metal ions in aqueous solution. In the textile industry , it prevents metal ion impurities from modifying colours of dyed products. In the pulp and paper industry , EDTA inhibits the ability of metal ions, especially Mn , from catalysing

152-470: A Patlak plot . Radionuclide therapy can be used to treat conditions such as hyperthyroidism , thyroid cancer , skin cancer and blood disorders. In nuclear medicine therapy, the radiation treatment dose is administered internally (e.g. intravenous or oral routes) or externally direct above the area to treat in form of a compound (e.g. in case of skin cancer). The radiopharmaceuticals used in nuclear medicine therapy emit ionizing radiation that travels only

228-534: A masking agent to sequester metal ions that would interfere with the analyses. EDTA finds many specialised uses in the biomedical labs, such as in veterinary ophthalmology as an anticollagenase to prevent the worsening of corneal ulcers in animals . In tissue culture , EDTA is used as a chelating agent that binds to calcium and prevents joining of cadherins between cells, preventing clumping of cells grown in liquid suspension, or detaching adherent cells for passaging . In histopathology , EDTA can be used as

304-523: A radionuclide into the body by intravenous injection in liquid or aggregate form, ingestion while combined with food, inhalation as a gas or aerosol, or rarely, injection of a radionuclide that has undergone micro-encapsulation . Some studies require the labeling of a patient's own blood cells with a radionuclide ( leukocyte scintigraphy and red blood cell scintigraphy). Most diagnostic radionuclides emit gamma rays either directly from their decay or indirectly through electron–positron annihilation , while

380-413: A values of free EDTA are 0, 1.5, 2, 2.66 ( deprotonation of the four carboxyl groups ) and 6.16, 10.24 (deprotonation of the two amino groups ). EDTA is in such widespread use that questions have been raised whether it is a persistent organic pollutant . While EDTA serves many positive functions in different industrial, pharmaceutical and other avenues, the longevity of EDTA can pose serious issues in

456-486: A decalcifying agent making it possible to cut sections using a microtome once the tissue sample is demineralised. EDTA is also known to inhibit a range of metallopeptidases , the method of inhibition occurs via the chelation of the metal ion required for catalytic activity. EDTA can also be used to test for bioavailability of heavy metals in sediments . However, it may influence the bioavailability of metals in solution, which may pose concerns regarding its effects in

532-443: A high affinity for metal cations: Written in this way, the equilibrium quotient shows that metal ions compete with protons for binding to EDTA. Because metal ions are extensively enveloped by EDTA, their catalytic properties are often suppressed. Finally, since complexes of EDTA are anionic , they tend to be highly soluble in water. For this reason, EDTA is able to dissolve deposits of metal oxides and carbonates . The p K

608-435: A higher Rem or Sv value, due to its much higher Relative Biological Effectiveness (RBE). Alpha emitters are nowadays rarely used in nuclear medicine, but were used extensively before the advent of nuclear reactor and accelerator produced radionuclides. The concepts involved in radiation exposure to humans are covered by the field of Health Physics ; the development and practice of safe and effective nuclear medicinal techniques

684-457: A lower toxicity after chelation, IDS is degraded by Agrobacterium tumefaciens (BY6), which can be harvested on a large scale. The enzymes involved, IDS epimerase and C−N lyase , do not require any cofactors . Polyaspartic acid , like IDS, binds to calcium and other heavy metal ions. It has many practical applications including corrosion inhibitors, wastewater additives, and agricultural polymers. A Polyaspartic acid-based laundry detergent

760-418: A nuclear medicine procedure will receive a radiation dose . Under present international guidelines it is assumed that any radiation dose, however small, presents a risk. The radiation dose delivered to a patient in a nuclear medicine investigation, though unproven, is generally accepted to present a very small risk of inducing cancer. In this respect it is similar to the risk from X-ray investigations except that

836-468: A particular section of the body (e.g.: chest X-ray, abdomen/pelvis CT scan, head CT scan, etc.). In addition, there are nuclear medicine studies that allow imaging of the whole body based on certain cellular receptors or functions. Examples are whole body PET scans or PET/CT scans, gallium scans , indium white blood cell scans , MIBG and octreotide scans . While the ability of nuclear metabolism to image disease processes from differences in metabolism

SECTION 10

#1732780821748

912-558: A rotating gamma-camera are reconstructed to produce an image of a "slice" through the patient at a particular position. A collection of parallel slices form a slice-stack, a three-dimensional representation of the distribution of radionuclide in the patient. The nuclear medicine computer may require millions of lines of source code to provide quantitative analysis packages for each of the specific imaging techniques available in nuclear medicine. Time sequences can be further analysed using kinetic models such as multi-compartment models or

988-423: A selective inhibitor against dNTP hydrolyzing enzymes ( Taq polymerase , dUTPase , MutT), liver arginase and horseradish peroxidase independently of metal ion chelation . These findings urge the rethinking of the utilisation of EDTA as a biochemically inactive metal ion scavenger in enzymatic experiments. In analytical chemistry, EDTA is used in complexometric titrations and analysis of water hardness or as

1064-706: A short distance, thereby minimizing unwanted side effects and damage to noninvolved organs or nearby structures. Most nuclear medicine therapies can be performed as outpatient procedures since there are few side effects from the treatment and the radiation exposure to the general public can be kept within a safe limit. In some centers the nuclear medicine department may also use implanted capsules of isotopes ( brachytherapy ) to treat cancer. The history of nuclear medicine contains contributions from scientists across different disciplines in physics, chemistry, engineering, and medicine. The multidisciplinary nature of nuclear medicine makes it difficult for medical historians to determine

1140-449: A similar manner, EDTA is added to some food as a preservative or stabiliser to prevent catalytic oxidative decolouration, which is catalysed by metal ions. The reduction of water hardness in laundry applications and the dissolution of scale in boilers both rely on EDTA and related complexants to bind Ca , Mg , as well as other metal ions. Once bound to EDTA, these metal complexes are less likely to form precipitates or to interfere with

1216-472: A sufficient amount of the procedure to achieve a diagnosis, then it would be inappropriate to proceed with injecting the patient with the radioactive tracer. When the benefit does justify the procedure, then the radiation exposure (the amount of radiation given to the patient) should also be kept "ALARP". This means that the images produced in nuclear medicine should never be better than required for confident diagnosis. Giving larger radiation exposures can reduce

1292-420: A type of preservative . The name comes from Latin and means "to withdraw from use" . Common sequestrants are: Sodium and calcium salts of EDTA are also commonly used in many foods and beverages. This food ingredient article is a stub . You can help Misplaced Pages by expanding it . Nuclear medicine Nuclear medicine ( nuclear radiology , nucleology ), is a medical specialty involving

1368-435: A viable alternative due to these features as well as biocompatibility , and biodegradability . A structural isomer of EDTA, ethylenediamine- N , N ′-disuccinic acid (EDDS) is readily biodegradable at high rate in its S , S form. Trisodium dicarboxymethyl alaninate , also known as methylglycinediacetic acid (MGDA), has a high rate of biodegradation at over 68%, but unlike many other chelating agents can degrade without

1444-701: Is a key focus of Medical Physics . Different countries around the world maintain regulatory frameworks that are responsible for the management and use of radionuclides in different medical settings. For example, in the US, the Nuclear Regulatory Commission (NRC) and the Food and Drug Administration (FDA) have guidelines in place for hospitals to follow. With the NRC, if radioactive materials aren't involved, like X-rays for example, they are not regulated by

1520-509: Is disease or pathology present. The radionuclide introduced into the body is often chemically bound to a complex that acts characteristically within the body; this is commonly known as a tracer . In the presence of disease, a tracer will often be distributed around the body and/or processed differently. For example, the ligand methylene-diphosphonate ( MDP ) can be preferentially taken up by bone. By chemically attaching technetium-99m to MDP, radioactivity can be transported and attached to bone via

1596-515: Is extracted. The F is then typically used to make FDG . Z = atomic number, the number of protons T 1/2 = half-life decay = mode of decay photons = principal photon energies in kilo-electron volts, keV , (abundance/decay) β = beta maximum energy in kilo-electron volts, keV , (abundance/decay) β = β decay ; β = β decay ; IT = isomeric transition ; ec = electron capture * X-rays from progeny, mercury , Hg A typical nuclear medicine study involves administration of

SECTION 20

#1732780821748

1672-485: Is not on imaging anatomy, but on the function. For such reason, it is called a physiological imaging modality . Single photon emission computed tomography (SPECT) and positron emission tomography (PET) scans are the two most common imaging modalities in nuclear medicine. In nuclear medicine imaging, radiopharmaceuticals are taken internally, for example, through inhalation, intravenously, or orally. Then, external detectors ( gamma cameras ) capture and form images from

1748-541: Is now used only to obtain the highest purities of lanthanides (typically greater than 99.99%). Sodium calcium edetate , an EDTA derivative, is used to bind metal ions in the practice of chelation therapy , such as for treating mercury and lead poisoning . It is used in a similar manner to remove excess iron from the body. This therapy is used to treat the complication of repeated blood transfusions , as would be applied to treat thalassaemia . In medical diagnosis and organ function tests (here, kidney function test),

1824-410: Is selected reaction monitoring capillary electrophoresis mass spectrometry (SRM-CE/MS), which has a detection limit of 7.3 ng/mL in human plasma and a quantitation limit of 15 ng/mL. This method works with sample volumes as small as 7–8 nL. EDTA has also been measured in non-alcoholic beverages using high performance liquid chromatography (HPLC) at a level of 2.0 μg/mL. In

1900-423: Is unsurpassed, it is not unique. Certain techniques such as fMRI image tissues (particularly cerebral tissues) by blood flow and thus show metabolism. Also, contrast-enhancement techniques in both CT and MRI show regions of tissue that are handling pharmaceuticals differently, due to an inflammatory process. Diagnostic tests in nuclear medicine exploit the way that the body handles substances differently when there

1976-691: The Washington University School of Medicine . These innovations led to fusion imaging with SPECT and CT by Bruce Hasegawa from University of California, San Francisco (UCSF), and the first PET/CT prototype by D. W. Townsend from University of Pittsburgh in 1998. PET and PET/CT imaging experienced slower growth in its early years owing to the cost of the modality and the requirement for an on-site or nearby cyclotron. However, an administrative decision to approve medical reimbursement of limited PET and PET/CT applications in oncology has led to phenomenal growth and widespread acceptance over

2052-409: The ammonia coproduct. To describe EDTA and its various protonated forms , chemists distinguish between EDTA, the conjugate base that is the ligand , and H 4 EDTA, the precursor to that ligand. At very low pH (very acidic conditions) the fully protonated H 6 EDTA form predominates, whereas at very high pH or very basic condition, the fully deprotonated EDTA form is prevalent. In this article,

2128-462: The chromium(III) complex [Cr(EDTA)] (as radioactive chromium-51 (Cr)) is administered intravenously and its filtration into the urine is monitored. This method is useful for evaluating glomerular filtration rate (GFR) in nuclear medicine . EDTA is used extensively in the analysis of blood. It is an anticoagulant for blood samples for CBC/FBCs , where the EDTA chelates the calcium present in

2204-507: The disproportionation of hydrogen peroxide , which is used in chlorine-free bleaching . Aqueous [Fe(EDTA)] is used for removing (" scrubbing ") hydrogen sulfide from gas streams. This conversion is achieved by oxidising the hydrogen sulfide to elemental sulfur, which is non-volatile: In this application, the iron(III) centre is reduced to its iron(II) derivative, which can then be reoxidised by air. In similar manner, nitrogen oxides are removed from gas streams using [Fe(EDTA)]. In

2280-629: The physical properties of the radiopharmaceutical used, its distribution in the body and its rate of clearance from the body. Effective doses can range from 6 μSv (0.006 mSv) for a 3 MBq chromium -51 EDTA measurement of glomerular filtration rate to 11.2 mSv (11,200 μSv) for an 80 MBq thallium -201 myocardial imaging procedure. The common bone scan with 600 MBq of technetium-99m MDP has an effective dose of approximately 2.9 mSv (2,900 μSv). Formerly, units of measurement were: The rad and rem are essentially equivalent for almost all nuclear medicine procedures, and only alpha radiation will produce

2356-844: The root canals in endodontics. This procedure helps prepare root canals for obturation . Furthermore, EDTA solutions with the addition of a surfactant loosen up calcifications inside a root canal and allow instrumentation (canal shaping) and facilitate apical advancement of a file in a tight or calcified root canal towards the apex. It serves as a preservative (usually to enhance the action of another preservative such as benzalkonium chloride or thiomersal ) in ocular preparations and eyedrops . Some alternative practitioners believe EDTA acts as an antioxidant , preventing free radicals from injuring blood vessel walls, therefore reducing atherosclerosis . These ideas are unsupported by scientific studies, and seem to contradict some currently accepted principles. The U.S. FDA has not approved it for

Ethylenediaminetetraacetic acid - Misplaced Pages Continue

2432-565: The tracer principle. Possibly, the genesis of this medical field took place in 1936, when John Lawrence , known as "the father of nuclear medicine", took a leave of absence from his faculty position at Yale Medical School , to visit his brother Ernest Lawrence at his new radiation laboratory (now known as the Lawrence Berkeley National Laboratory ) in Berkeley , California . Later on, John Lawrence made

2508-607: The 1930s. The history of nuclear medicine will not be complete without mentioning these early pioneers. Nuclear medicine gained public recognition as a potential specialty when on May 11, 1946, an article in the Journal of the American Medical Association (JAMA) by Massachusetts General Hospital's Dr. Saul Hertz and Massachusetts Institute of Technology's Dr. Arthur Roberts, described the successful use of treating Graves' Disease with radioactive iodine (RAI)

2584-453: The 1960s became a practical method for medical use. Today, Technetium-99m is the most utilized element in nuclear medicine and is employed in a wide variety of nuclear medicine imaging studies. Widespread clinical use of nuclear medicine began in the early 1950s, as knowledge expanded about radionuclides, detection of radioactivity, and using certain radionuclides to trace biochemical processes. Pioneering works by Benedict Cassen in developing

2660-420: The action of the soaps and detergents . For similar reasons, cleaning solutions often contain EDTA. In a similar manner EDTA is used in the cement industry for the determination of free lime and free magnesia in cement and clinkers . The solubilisation of Fe ions at or below near neutral pH can be accomplished using EDTA. This property is useful in agriculture including hydroponics. However, given

2736-644: The agency and instead are regulated by the individual states. International organizations, such as the International Atomic Energy Agency (IAEA), have regularly published different articles and guidelines for best practices in nuclear medicine as well as reporting on emerging technologies in nuclear medicine. Other factors that are considered in nuclear medicine include a patient's medical history as well as post-treatment management. Groups like International Commission on Radiological Protection have published information on how to manage

2812-458: The anatomy and function, which would otherwise be unavailable or would require a more invasive procedure or surgery. Although the risks of low-level radiation exposures are not well understood, a cautious approach has been universally adopted that all human radiation exposures should be kept As Low As Reasonably Practicable , "ALARP". (Originally, this was known as "As Low As Reasonably Achievable" (ALARA), but this has changed in modern draftings of

2888-561: The appearance of a "cold spot". Many tracer complexes have been developed to image or treat many different organs, glands, and physiological processes. In some centers, the nuclear medicine scans can be superimposed, using software or hybrid cameras, on images from modalities such as CT or MRI to highlight the part of the body in which the radiopharmaceutical is concentrated. This practice is often referred to as image fusion or co-registration, for example SPECT/CT and PET/CT. The fusion imaging technique in nuclear medicine provides information about

2964-400: The application of radioactive substances in the diagnosis and treatment of disease . Nuclear imaging is, in a sense, radiology done inside out , because it records radiation emitted from within the body rather than radiation that is transmitted through the body from external sources like X-ray generators . In addition, nuclear medicine scans differ from radiology, as the emphasis

3040-535: The assistance of adapted bacteria. Additionally, unlike EDDS or IDS, MGDA can withstand higher temperatures while maintaining a high stability as well as the entire pH range. MGDA has been shown to be an effective chelating agent, with a capacity for mobilization comparable with that of nitrilotriacetic acid (NTA), with application to water for industrial use and for the removal of calcium oxalate from urine from patients with kidney stones . The most sensitive method of detecting and measuring EDTA in biological samples

3116-619: The backbone and acetyl groups were attacked. Some microorganisms have even been discovered to form nitrates out of EDTA, but they function optimally at moderately alkaline conditions of pH 9.0–9.5. Several bacterial strains isolated from sewage treatment plants efficiently degrade EDTA. Specific strains include Agrobacterium radiobacter ATCC 55002 and the sub-branches of Pseudomonadota like BNC1, BNC2, and strain DSM 9103. The three strains share similar properties of aerobic respiration and are classified as gram-negative bacteria . Unlike photolysis,

Ethylenediaminetetraacetic acid - Misplaced Pages Continue

3192-534: The birthdate of nuclear medicine. This can probably be best placed between the discovery of artificial radioactivity in 1934 and the production of radionuclides by Oak Ridge National Laboratory for medicine-related use, in 1946. The origins of this medical idea date back as far as the mid-1920s in Freiburg , Germany, when George de Hevesy made experiments with radionuclides administered to rats, thus displaying metabolic pathways of these substances and establishing

3268-536: The blood specimen, arresting the coagulation process and preserving blood cell morphology. Tubes containing EDTA are marked with lavender (purple) or pink tops. EDTA is also in tan top tubes for lead testing and can be used in royal blue top tubes for trace metal testing. EDTA is a slime dispersant, and has been found to be highly effective in reducing bacterial growth during implantation of intraocular lenses (IOLs). Dentists and endodontists use EDTA solutions to remove inorganic debris ( smear layer ) and lubricate

3344-778: The cell-damaging properties of beta particles are used in therapeutic applications. Refined radionuclides for use in nuclear medicine are derived from fission or fusion processes in nuclear reactors , which produce radionuclides with longer half-lives, or cyclotrons , which produce radionuclides with shorter half-lives, or take advantage of natural decay processes in dedicated generators, i.e. molybdenum/technetium or strontium/rubidium. The most commonly used intravenous radionuclides are technetium-99m, iodine-123, iodine-131, thallium-201, gallium-67, fluorine-18 fluorodeoxyglucose , and indium-111 labeled leukocytes . The most commonly used gaseous/aerosol radionuclides are xenon-133, krypton-81m, ( aerosolised ) technetium-99m. A patient undergoing

3420-589: The chelated species is not exclusive to iron(III) in order to be degraded. Rather, each strain uniquely consumes varying metal–EDTA complexes through several enzymatic pathways. Agrobacterium radiobacter only degrades Fe(III) EDTA while BNC1 and DSM 9103 are not capable of degrading iron(III) EDTA and are more suited for calcium , barium , magnesium and manganese(II) complexes. EDTA complexes require dissociation before degradation. Interest in environmental safety has raised concerns about biodegradability of aminopolycarboxylates such as EDTA. These concerns incentivize

3496-465: The dose is delivered internally rather than from an external source such as an X-ray machine, and dosage amounts are typically significantly higher than those of X-rays. The radiation dose from a nuclear medicine investigation is expressed as an effective dose with units of sieverts (usually given in millisieverts, mSv). The effective dose resulting from an investigation is influenced by the amount of radioactivity administered in mega becquerels (MBq),

3572-780: The environment, especially given its widespread uses and applications. The oxidising properties of [Fe(EDTA)] are used in photography to solubilise silver particles. EDTA is also used to remove crud (corroded metals) from fuel rods in nuclear reactors. EDTA exhibits low acute toxicity with LD 50 (rat) of 2.0 g/kg to 2.2 g/kg. It has been found to be both cytotoxic and weakly genotoxic in laboratory animals. Oral exposures have been noted to cause reproductive and developmental effects. The same study also found that both dermal exposure to EDTA in most cosmetic formulations and inhalation exposure to EDTA in aerosolised cosmetic formulations would produce exposure levels below those seen to be toxic in oral dosing studies. The compound

3648-475: The environment. The degradation of EDTA is slow. It mainly occurs abiotically in the presence of sunlight. The most important process for the elimination of EDTA from surface waters is direct photolysis at wavelengths below 400 nm. Depending on the light conditions, the photolysis half-lives of iron(III) EDTA in surface waters can range as low as 11.3 minutes up to more than 100 hours. Degradation of FeEDTA, but not EDTA itself, produces iron complexes of

3724-448: The first rectilinear scanner and Hal O. Anger 's scintillation camera ( Anger camera ) broadened the young discipline of nuclear medicine into a full-fledged medical imaging specialty. By the early 1960s, in southern Scandinavia , Niels A. Lassen , David H. Ingvar , and Erik Skinhøj developed techniques that provided the first blood flow maps of the brain, which initially involved xenon-133 inhalation; an intra-arterial equivalent

3800-402: The first application in patients of an artificial radionuclide when he used phosphorus-32 to treat leukemia . Many historians consider the discovery of artificially produced radionuclides by Frédéric Joliot-Curie and Irène Joliot-Curie in 1934 as the most significant milestone in nuclear medicine. In February 1934, they reported the first artificial production of radioactive material in

3876-508: The formation of an additional bond to water, i.e. seven-coordinate complexes, or the displacement of one carboxylate arm by water. The iron(III) complex of EDTA is seven-coordinate. Early work on the development of EDTA was undertaken by Gerold Schwarzenbach in the 1940s. EDTA forms especially strong complexes with Mn(II) , Cu(II) , Fe(III), Pb(II) and Co(III). Several features of EDTA's complexes are relevant to its applications. First, because of its high denticity , this ligand has

SECTION 50

#1732780821748

3952-421: The hydroxyapatite for imaging. Any increased physiological function, such as due to a fracture in the bone, will usually mean increased concentration of the tracer. This often results in the appearance of a "hot spot", which is a focal increase in radio accumulation or a general increase in radio accumulation throughout the physiological system. Some disease processes result in the exclusion of a tracer, resulting in

4028-500: The invention of the first positron emission tomography scanner ( PET ). The concept of emission and transmission tomography, later developed into single photon emission computed tomography (SPECT), was introduced by David E. Kuhl and Roy Edwards in the late 1950s. Their work led to the design and construction of several tomographic instruments at the University of Pennsylvania. Tomographic imaging techniques were further developed at

4104-557: The investigation of alternative aminopolycarboxylates. Candidate chelating agents include nitrilotriacetic acid (NTA), iminodisuccinic acid (IDS), polyaspartic acid , S,S -ethylenediamine- N , N ′-disuccinic acid (EDDS) , methylglycinediacetic acid (MGDA), and L -Glutamic acid N , N -diacetic acid, tetrasodium salt (GLDA). Commercially used since 1998, iminodisuccinic acid (IDS) biodegrades by about 80% after only 7 days. IDS binds to calcium exceptionally well and forms stable compounds with other heavy metal ions. In addition to having

4180-440: The journal Nature , after discovering radioactivity in aluminum foil that was irradiated with a polonium preparation. Their work built upon earlier discoveries by Wilhelm Konrad Roentgen for X-ray, Henri Becquerel for radioactive uranium salts, and Marie Curie (mother of Irène Curie) for radioactive thorium, polonium and coining the term "radioactivity." Taro Takemi studied the application of nuclear physics to medicine in

4256-411: The last few years, which also was facilitated by establishing 18F-labelled tracers for standard procedures, allowing work at non-cyclotron-equipped sites. PET/CT imaging is now an integral part of oncology for diagnosis, staging and treatment monitoring. A fully integrated MRI/PET scanner is on the market from early 2011. Tc is normally supplied to hospitals through a radionuclide generator containing

4332-460: The legislation to add more emphasis on the "Reasonably" and less on the "Achievable".) Working with the ALARP principle, before a patient is exposed for a nuclear medicine examination, the benefit of the examination must be identified. This needs to take into account the particular circumstances of the patient in question, where appropriate. For instance, if a patient is unlikely to be able to tolerate

4408-424: The movie Blade (1998), EDTA is used as a weapon to kill vampires, exploding when in contact with vampire blood. Sequestrant A sequestrant is a food additive which improves the quality and stability of foods. A sequestrant forms chelate complexes with polyvalent metal ions, especially copper , iron and nickel . This can prevent the oxidation of the fats in the food. Sequestrants are therefore

4484-476: The noise in an image and make it more photographically appealing, but if the clinical question can be answered without this level of detail, then this is inappropriate. As a result, the radiation dose from nuclear medicine imaging varies greatly depending on the type of study. The effective radiation dose can be lower than or comparable to or can far exceed the general day-to-day environmental annual background radiation dose. Likewise, it can also be less than, in

4560-417: The nuclear medicine imaging process is a dataset comprising one or more images. In multi-image datasets the array of images may represent a time sequence (i.e. cine or movie) often called a "dynamic" dataset, a cardiac gated time sequence, or a spatial sequence where the gamma-camera is moved relative to the patient. SPECT (single photon emission computed tomography) is the process by which images acquired from

4636-412: The pH dependence of ligand formation, EDTA is not helpful for improving iron solubility in above neutral soils. Otherwise, at near-neutral pH and above, iron(III) forms insoluble salts, which are less bioavailable to susceptible plant species. EDTA was used in separation of the lanthanide metals by ion-exchange chromatography . Perfected by F. H. Spedding et al . in 1954, the method relies on

SECTION 60

#1732780821748

4712-548: The parent radionuclide molybdenum-99 . Mo is typically obtained as a fission product of U in nuclear reactors, however global supply shortages have led to the exploration of other methods of production . About a third of the world's supply, and most of Europe's supply, of medical isotopes is produced at the Petten nuclear reactor in the Netherlands . Another third of the world's supply, and most of North America's supply,

4788-701: The radiation emitted by the radiopharmaceuticals. This process is unlike a diagnostic X-ray, where external radiation is passed through the body to form an image. There are several techniques of diagnostic nuclear medicine. Nuclear medicine tests differ from most other imaging modalities in that nuclear medicine scans primarily show the physiological function of the system being investigated as opposed to traditional anatomical imaging such as CT or MRI. Nuclear medicine imaging studies are generally more organ-, tissue- or disease-specific (e.g.: lungs scan, heart scan, bone scan, brain scan, tumor, infection, Parkinson etc.) than those in conventional radiology imaging, which focus on

4864-408: The range of, or higher than the radiation dose from an abdomen/pelvis CT scan. Some nuclear medicine procedures require special patient preparation before the study to obtain the most accurate result. Pre-imaging preparations may include dietary preparation or the withholding of certain medications. Patients are encouraged to consult with the nuclear medicine department prior to a scan. The result of

4940-436: The steady increase in stability constant of the lanthanide EDTA complexes with atomic number . Using sulfonated polystyrene beads and Cu as a retaining ion, EDTA causes the lanthanides to migrate down the column of resin while separating into bands of pure lanthanides. The lanthanides elute in order of decreasing atomic number. Due to the expense of this method, relative to countercurrent solvent extraction , ion exchange

5016-671: The term EDTA is used to mean H 4− x EDTA, whereas in its complexes EDTA stands for the tetraanion ligand. In coordination chemistry , EDTA is a member of the aminopolycarboxylic acid family of ligands. EDTA usually binds to a metal cation through its two amines and four carboxylates, i.e., it is a hexadentate ("six-toothed") chelating agent . Many of the resulting coordination compounds adopt octahedral geometry . Although of little consequence for its applications, these octahedral complexes are chiral . The cobalt(III) anion [Co(EDTA)] has been resolved into enantiomers . Many complexes of EDTA adopt more complex structures due to either

5092-499: The thyroid gland, quantification of the thyroid function, and therapy for hyperthyroidism. Among the many radionuclides that were discovered for medical-use, none were as important as the discovery and development of Technetium-99m . It was first discovered in 1937 by C. Perrier and E. Segre as an artificial element to fill space number 43 in the Periodic Table. The development of a generator system to produce Technetium-99m in

5168-481: The treatment of atherosclerosis. In shampoos , cleaners, and other personal care products, EDTA salts are used as a sequestering agent to improve their stability in air. In the laboratory, EDTA is widely used for scavenging metal ions: In biochemistry and molecular biology , ion depletion is commonly used to deactivate metal-dependent enzymes , either as an assay for their reactivity or to suppress damage to DNA , proteins , and polysaccharides . EDTA also acts as

5244-458: The triacetate (ED3A), diacetate (EDDA), and monoacetate (EDMA) – 92% of EDDA and EDMA biodegrades in 20 hours while ED3A displays significantly higher resistance. Many environmentally-abundant EDTA species (such as Mg and Ca ) are more persistent. In many industrial wastewater treatment plants, EDTA elimination can be achieved at about 80% using microorganisms . Resulting byproducts are ED3A and iminodiacetic acid (IDA) – suggesting that both

5320-590: Was also used to investigate, e.g., imagined sequential movements, mental calculation and mental spatial navigation. By the 1970s most organs of the body could be visualized using nuclear medicine procedures. In 1971, American Medical Association officially recognized nuclear medicine as a medical specialty. In 1972, the American Board of Nuclear Medicine was established, and in 1974, the American Osteopathic Board of Nuclear Medicine

5396-432: Was developed soon after, enabling measurement of the local distribution of cerebral activity for patients with neuropsychiatric disorders such as schizophrenia. Later versions would have 254 scintillators so a two-dimensional image could be produced on a color monitor. It allowed them to construct images reflecting brain activation from speaking, reading, visual or auditory perception and voluntary movement. The technique

5472-424: Was established, cementing nuclear medicine as a stand-alone medical specialty. In the 1980s, radiopharmaceuticals were designed for use in diagnosis of heart disease. The development of single photon emission computed tomography (SPECT), around the same time, led to three-dimensional reconstruction of the heart and establishment of the field of nuclear cardiology. More recent developments in nuclear medicine include

5548-530: Was first described in 1935 by Ferdinand Münz , who prepared the compound from ethylenediamine and chloroacetic acid . Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde , and sodium cyanide . This route yields the tetrasodium EDTA, which is converted in a subsequent step into the acid forms: This process is used to produce about 80,000 tonnes of EDTA each year. Impurities cogenerated by this route include glycine and nitrilotriacetic acid ; they arise from reactions of

5624-640: Was produced at the Chalk River Laboratories in Chalk River , Ontario , Canada until its permanent shutdown in 2018. The most commonly used radioisotope in PET, F , is not produced in a nuclear reactor, but rather in a circular accelerator called a cyclotron . The cyclotron is used to accelerate protons to bombard the stable heavy isotope of oxygen O . The O constitutes about 0.20% of ordinary oxygen (mostly oxygen-16 ), from which it

5700-436: Was published. Additionally, Sam Seidlin . brought further development in the field describing a successful treatment of a patient with thyroid cancer metastases using radioiodine ( I-131 ). These articles are considered by many historians as the most important articles ever published in nuclear medicine. Although the earliest use of I-131 was devoted to therapy of thyroid cancer, its use was later expanded to include imaging of

5776-530: Was the first laundry detergent in the world to receive the EU flower ecolabel . Calcium binding ability of polyaspartic acid has been exploited for targeting of drug-loaded nanocarriers to bone. Preparation of hydrogels based on polyaspartic acid, in a variety of physical forms ranging from fiber to particle , can potentially enable facile separation of the chelated ions from a solution. Therefore, despite being weaker than EDTA, polyaspartic acid can still be regarded as

#747252