Medicine positron emission tomography

Mysteries such as this attract young people to science. Nuclear physics, however, tends to turn people off Nuclear power plant malfunctions and atomic bombs are frightening. Nevertheless, humankind has greatly benefited from scientific investigations of the nucleus. Science s hard-won knowledge of the atomic nucleus is used extensively in medicine, from imaging procedures such as positron emission tomography (PET) to radiation therapy, which has saved the lives of many cancer patients. 

Nuclear medicine is used chiefly in medical diagnosis. A radiopharmaceutical—a relatively harmless compound with a low dose of radiation— is swallowed or injected into the patient and tracked through the bloodstream by instruments such as a PET (positron emission tomography) camera. The nuclear physician can use the results to create a... 

Eowler JS (1993) The synthesis and application of F-18 compounds in positron emission tomography. In Filler R (eds) Organofluorine compounds in medicinal chemistry and biomedical applications. Elsevier Science Publishers BV, Amsterdam, p 309... 

Stocklin G, Pike VW (eds) (1993) Radiopharmaceuticals for positron emission tomography. Cox PH (series ed) Development in nuclear medicine, vol 24, Klimder Academic Publishers, Dordrecht... 

Positron emission tomography (PET) is a high-resolution, sensitive, functionalimaging technique in nuclear medicine that permits repeated, non-invasive... 

R. Kumar, S. Jana, Positron emission tomography An advanced nuclear medicine imaging technique from research to clinical practice. Methods Enzymol. 385 (2004) 3-19. 

A recent development in nuclear medicine that illustrates how advances in basic research are transformed into practical applications is positron emission tomography or PET. PET creates a three-dimensional image of a body part using positron emitting isotopes. Positrons, positively charged electrons, are a form of antimatter. Antimatter consists of particles that have the same mass as ordinary matter, but differ in charge or some other property. For example, antipro-... 

Three new positron emitting generator systems have been described. The practical availability of these radionuclides could significantly broaden the potential applications of positron emission tomography. The next few years should see human clinical trials undertaken to fully evaluate their utility for nuclear medicine. 

Yiu Timothy J. McCarthy, Sally W. MJI Schwarz, and Michael J. Welch, "Nuclear Medicine and Positron Emission Tomography ... 

To monitor tumor response to capecitabine therapy noninvasively, Zheng and co-workers, from the Indiana University School of Medicine, developed the synthesis of the fluorine- 18-labeled capecitabine as a potential radiotracer for positron emission tomography (PET) imaging of tumors.28 Cytosine (20) was nitrated at the C-5 position with nitric acid in concentrated sulfuric acid at 85°C, followed by neutralization to provide 5-nitrocytosine (27) in moderate yield. This nitro pyrimidine was then carried through the glycosylation and carbamate formation steps, as shown in the Scheme below, to provide the 6/s-protected 5-nitro cytidine 28 in 47% for the three-step process. Precursor 28 was then labeled by nucleophilic substitution with a complex of 18F-labeled potassium fluoride with cryptand Kryptofix 222 in DMSO at 150 °C to provide the fluorine-18-labe led adduct. This intermediate was not isolated, but semi-purified and deprotected with aqueous NaOH in methanol to provide [l8F]-capecitabine in 20-30% radiochemical yield for the 3-mg-scale process. The synthesis time for fluorine-18 labeled capecitabine (including HPLC purification) from end of bombardment to produce KI8F to the final formulation of [18F]-1 for in vivo studies was 60-70 min. 

The use of nanoparticles and other macromolecular delivery vehicles in clinical medicine is not only limited to therapy but also offers novel diagnostic tools. Perhaps, the most promising methodology in this direction is positron emission tomography (PET), which has the capability of enhancing the specificity... 

Hence Eq. (3.6.15) is not merely an academic exercise Indeed, positron emission tomography (PET) is a known analytical technique used in medicine (the annihilation rate is subtly spindependent and varies, depending on the type of human body tissue traversed). When matter and antimatter collide in the universe, they annihilate each other in a cosmic version of Eq. (3.6.15). 

Positron emission tomography has become a widely used diagnostic technique in nuclear medicine. Ultrashort half-live radionuclides are used in these cases, and such radionuclides are mostly obtained in small cyclotrons with high yields and short irradiation times. The overall process will be described further in this chapter when PET radiopharmaceuticals are described. 

Many ft emitters do not eject electrons but positrons (ft partides), as for example 22Na and 65Zn. Short lived positron emitters are used in positron emission tomography (PET) in nuclear medicine studies, particularly of the brain. 

Several positron emitters are of practical importance in nuclear medicine for positron emission tomography (PET). Some are listed in Table 12.6. Protons or deuterons with energies varying between about 10 and 40MeV are available in small cyclotrons ( baby cyclotrons ) and are applied for the production of suitable radionuclides. 

G. Stocklin, V. W. Pike (Eds.), Radiopharmaceuticals for Positron Emission Tomography, Methodological Aspects, Developments in Nuclear Medicine, Vol. 24, Kluwer Academic Publ., Dordrecht, Boston, London, 1993... 

Nowadays, nuclear medicine has become an indispensible section of medical science, and the production of radionuclides and labelled compounds for application in nuclear medicine is an important branch of nuclear and radiochemistry. The development of radionuclide generators made short-lived radionuclides available at any time for medical application. New imaging devices, such as single photon emission tomography (SPET) and positron emission tomography (PET) made it possible to study local biochemical reactions and their kinetics in the living human body. 

The production of short-lived positron emitters has been described in section 12.2. By interaction with electrons, the positrons are annihilated and two y-ray photons of 511 keV each are emitted simultaneously in opposite directions. By measuring these photons by means of a suitable arrangement of detectors, exact localization of the radionuclides in the body is possible. This is the basis of positron emission tomography (PET), which has found broad application in nuclear medicine. The most frequently used positron emitters are listed in Table 19.2. They are preferably produced by small cyclotrons in the hospitals or nearby. 

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