Therapeutic radioisotopes

Wambersie A. International Atomic Energy Agency (IAEA), International Nuclear Data Committee, Nuclear Data for Production of Therapeutic Radioisotopes, INDC (NDS)-432, IAEA Vienna, 2002. 

In addition to studies of classic bone seeking pharmaceuticals with a therapeutic potential, an evaluation was made of the receptor ligand peptide TATE to determine its potential as a diagnostic radiopharmaceutical (chelated by HYNIC and labelled with T) and as a therapeutic one (chelated by DOTA and labelled with therapeutic radioisotopes ( °Y and Lu) and a diagnostic isotope ( 4n)). 

This report is divided into two sections. The first deals with the radio-labeUing, biodistribution and biological studies of bone seeking and tumour specific molecules radiolabelled with Re. The second section deals with the studies of radiolabelled receptor-Ugand conjugates with diagnostic and therapeutic radioisotopes. 

A polyazamacrocyclic-nitrotriazole conjugate for radiolabelling with the therapeutic radioisotope Lu was prepared. The nitroimidazole used for the... 

Radiopharmaceutical, to be prepared and administered only by personnel trained in radiopharmaceuticals premedicate with acetaminophen and antihistamines slow infusion rate or interrupt infusion for infusion reactions medications for treatment of hypersensitivity reactions should be available for immediate use avoid in pregnant females may cause hypothyroidism in fetus two-step administration MoAB and low radioisotope dose is followed after 1-2 weeks by MoAB and therapeutic radioisotope dose renally excreted impaired renal function may increase exposure to radioactive components patients must be trained in precautions to decrease radiation exposure to family, friends, and general public... 

The radioisotopes that are used exclusively for the treatment of various diseases are generally known as therapeutic radioisotopes. The following Table contains the different ranges of therapeutic radioisotopes ... 

Figure 1. Division of nuclear medicine into diagnostic and therapeutic radioisotopes.

Radionuclide production technology at cyclotrons has been well developed, especially for short-lived organic positron emitters, commonly used SPECT radionuclides, and a few therapeutic radioisotopes. In this regard, all components of the technology, i.e., spedal purpose cyclotrons, high current irradiation targets, and automated or remotely controlled chemical processing units can now be purchased. Furthermore, four commonly used cyclotron pro-... 

Radioisotopes behave chemically like nonradioisotopes of the same element and can be used diagnostically and therapeutically. Diagnostically, radioisotopes are used as tracers whose movement or localization in the body can be followed. Therapeutic radioisotopes localize in diseased areas of the body, where their radiation can destroy diseased tissue. 

IEC continues to have numerous applications to the detection and quantification of various inorganic ions.1 1 This is particularly true in water analysis.5-14 Inorganic ions in a variety of other sample types, such as food and beverages,1518 rocks,19-23 biological fluids, (blood, urine, etc.),24-31 pharmaceutical substances,32 33 concentrated acids,34 alcohols,35 and cleanroom air36 have also been analyzed by IEC. IEC has also been employed in isotopic separation of ions,37 including the production of radioisotopes for therapeutic purposes.3839 Typical IEC sample matrices are complex, and may contain substances that interfere with measurement of the ion(s) of interest. The low detection limits required for many IEC separations demand simple extraction procedures and small volumes to avoid over-dilution. Careful choice and manipulation of the eluent(s) may be needed to achieve the desired specificity, especially when multiple ions are to be determined in a single sample. 

If the excess of lanthanide is sufficiently great, overloading of the transport system occurs and colloidal aggregates of large size are formed by hydrolysis. The interstitial or intracavitary formation of immobilized lanthanide colloids labeled with relatively short-lived radioisotopes was the basis for the attempted use of radioactive lanthanides as internal sources of therapeutic radiation (Kyker, 1962a, 1962b). 

The antibody preparations could be administered unaltered or (more commonly) after their conjugation to radioisotopes or toxins. Binding of unaltered monoclonal antibodies to a tumour surface alone should facilitate increased destruction of tumour cells (Figure 13.4). This approach, however, has yielded disappointing results, as the monoclonal antibody preparations used to date have been murine in origin. The Fc region of such mouse antibodies is a very poor activator of human immune function. Technical advances, allowing the production of human/humanized monoclonals (see later) may render this therapeutic approach more attractive in the future. 

Prominent among the elements that provide a selection of radioisotopes with therapeutically useful radiological properties is rhenium. It is attractive for a variety of reasons ... 

Radiophannaceuticals are almost ideal diagnostic tools because radioisotope tracers do not alter body physiology, and they permit external monitoring with minimal instrumentation. Presently, there are three major areas of nuclear medicine (1) physiological function studies, (2) radionuclide imaging procedures, and (3) therapeutic techniques. 

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