Radiotherapeutics

Cobalt-60, an artificial isotope, is an important gamma ray source, and is extensively used as a tracer and a radiotherapeutic agent. 

This reaction offers the advantage of a superior neutron yield of in a thermal reactor system. The abiHty to breed fissile from naturally occurring Th allows the world s thorium reserves to be added to its uranium reserves as a potential source of fission power. However, the Th/ U cycle is unlikely to be developed in the 1990s owing both to the more advanced state of the / Pu cycle and to the avadabiHty of uranium. Thorium is also used in the production of the cx-emitting radiotherapeutic agent, Bi, via the production of Th and subsequent decay through Ac (20). 

Reinhoudt et al. also reported water-soluble pseudorotaxane-terminated dendrimers possessing a radio-active metal core for radiotherapeutical applications... 

EGER targeting was also used for systemic delivery of pDNA expressing the sodium iodide symporter (NIS) gene to liver cancer cells, followed by administration of radioactive isotope iodine-131, which accumulates in the tumor by NIS-mediated uptake in radiotherapeutic doses [227]. 

Hartman KB, Hamlin DK, Wilbur DS, Wilson LJ (2007) 211AtCl US-tube nanocapsules a new concept in radiotherapeutic-agent design. Small 3 1496-1499. 

At-MNDP 31-33, 36, 108), whose mechanism of intracellular localization is related to the presence of oncogenically expressed tumor-membrane alkaline phosphatase isoenzymes 42, 108), has been demonstrated strikingly effective in an animal tumor model 33, 34, 38, 39). It has also served as a concomitant analytical probe for identifying the intracellular locus of radiotherapeutic action of this class of drug by a-particle track autoradiography 33,106-109). Phase I and II human therapeutic trials are shortly envisaged 33, 34). 

An extremely ill 51-year-old man with Cushing s syndrome, due to an ACTH-secreting pituitary macroadenoma, which had failed to respond to conventional surgical, medical, and radiotherapeutic approaches, responded dramatically in the short-term and long-term to high-dose mifepristone (up to 25 mg/kg/day) for 18 months. However, she developed severe hypokalemia, attributed to excessive cortisol activation of mineralocor-ticoid receptors it responded to spironolactone. 

Campbell JM, Schulte-Frohlinde D, von Sonntag C (1974) Quantum yields in the UV photolysis of 5-bromo-uracil in the presence of hydrogen donors. Photochem Photobiol 20 465-467 Chapman JD (1984) The cellular basis of radiotherapeutic response. Radiat Phys Chem 24 283-291 Chatterjee M, Mah SC, Tullius TD, Townsend CA (1995) Role of the aryl iodide in the sequence-selective cleavage of DNA by calicheamicin. Importance of thermodynamic binding vs kinetic activation process. J Am Chem Soc 117 8074-8082 Chaudry MA, Weinfeld M (1995) The action of Escherichia coli endonuclease III on multiply damaged sites in DNA. J Mol Biol 249 914-922... 

Laskar SG, Agarwal JP, Srinivas C, Dinshaw KA. Radiotherapeutic management of locally advanced head and neck cancer. Expert Rev Anticancer Ther. 2006 6 405M17. 

Fig. 7.3 Radiotherapeutics (from top) DOTA—tyr3-octreotide, LUTRIN and Lu-177-AMDA...

Maddalena ME et al (2009) Lu-177-AMBA biodistribution, radiotherapeutic efficacy, imaging, and autoradiography in prostate cancer models with low GRP-R expression. J Nucl Med 50 2017-2024... 

Radiotherapeutics attack cancer by causing radiation damage to DNA in cells. The requirements differ from those for drug delivery because the radiotherapeutic can act at a distance and does not have to separate from the delivery particle. Radiotherapeutics can be selected to provide action over a range of distances, from tens of nanometers to hundreds of microns. Three radiotherapy modalities can be identified. Brachytherapy, most often used with beta-emitters, uses tightly enclosed radioactive material that is brought in close proximity to the tumor. A second modality is intravenous injection so that the radiopharmaceutical binds to the outside of the tumor cells or is taken up by the cell and irradiates from within. The third approach uses a carrier loaded with the radiotherapeutic that is transported to the vicinity of the target cells, and then released. 

B. Syntheses of211 At-Labelled Compounds for Radiotherapeutic Uses. . . 498... 

Bismuth (Z = 83) is the heaviest stable element in group 15 (VA) of the periodic table (see Periodic Table Trends in the Properties of the Elements). The Bi isotope, which is 100% abundant, has a 9/2 nuclear spin. Bi, an alpha emitter is used in nuclear medicine as a radiotherapeutic agent. Bismuth has two stable oxidation states Bi(V), corresponding to complete loss of the valence electrons, and Bi(III), a lower oxidation state that retains two valence electrons. Both oxidation states are diamagnetic. The latter is more stable and more common since Bi(V) has a large reduction potential ... 

---