Radioisotopes indium

Anderson et al. examined the effect of altering inspiratory flow rate on the regional lung deposition of inert particles and on the pulmonary response to histamine aerosol. In one experiment, six healthy nonsmokers inhaled 6-pm Teflon particles that were labeled with the radioisotope indium 111 (" In) at 0.04 and 0.5 L/s. Tracheobronchial deposition averaged 50% after inhaling at 0.04 L/s, compared to 30% after inhaling at 0.5 L/s. Alveolar deposition increased from 1 to 28% with the lower inspiratory rate (69). 

Imura and Suzuki36 have prepared labelled organotin compounds from artificial tin isotopes produced in a cyclotron. The carrier-free tin-113 radioisotope was produced by irradiating indium-115 oxide with 40-MeV protons (equation 33). 

Radioactive labels are -emitters selected on the basis of half-lives, the energies emitted, decay products, ease of labeling, availability and expense. Iodine isotopes 121,123, and 124, Indium 111, and Technetium 99 are the labels most widely used. The short half-lives of these labels (hours to days) means that radioimaging reagents are prepared immediately prior to treatment. Radioimaging of diseased tissue also provides useful information on the design of therapies that localize radioisotopes or toxins at tumor sites for therapy. 

Table III is a compilation of the parameters in a typical Cd-109 production run. A sealed stainless steel tube containing 105.8 g of indium was positioned in the proton beam for 56 days. Since the beam was not on continuously for this 56-day period, the integrated exposure of the target was not available. A total of 1553 mCi of Cd-109 was produced with 1427 mCi recovered giving a 92% recovery. The only other radioisotope found was 117 mCi of Cd-115m which cannot be separated.

The half-life of indium-111, a radioisotope used in studying the distribution of white blood cells, is h/2 = 2.805 days. What is the decay constant of11 in ... 

The most useful radioisotope of indium is indium-ill. which is produced in a cyclotron by proton bombardment of a cadmium metal target by a Cd(p.2n)" nuclear reaction. 

Thallium sulfate used to be used to kill ants and rats, but the extremely high toxicity levels of T1 compounds are now well recognized and aU Tl-containing species must be treated with caution. The world production of thalhum (15 000 kg in 2001) is far less than that of galhum (Figure 12.3) and indium. Important uses of T1 are in semiconducting materials in selenium rectifiers, in Tl-activated NaCl and Nal crystals in 7-radiation detectors, and in IR radiation detection and transmission equipment. The radioisotope T1 h = 12.2d) is used for cardiovascular imaging. 

Radiolabeled Compounds of Biomedical Interest Containing Radioisotopes of Gallium and Indium... 

Indium Symbol In. A soft silvery element belonging to group 13 (formerly IIIB) of the periodic table a.n. 49 r.a.m. 114.82 r.d. 7.31 (20°C) m.p. 156.6°C b.p. 2080 2°C. It occurs in zinc blende and some iron ores and is obtained from zinc flue dust in total quantities of about 40 tonnes per annum. Naturally occurring indium consists of 4.23% indium-1 13 (stable) and 95.77% indium-115 (half-life 6x10 years). There are a further five short-lived radioisotopes. The uses of the metal are small - some special-purpose electroplates and some special fusible alloys. Several semiconductor compounds are used, such as InAs, InP, and InSb. With only three electrons in its valency shell, indium is an electron acceptor and is used to dope pure germanium and silicon it forms stable in-dium(I), indium(II), and indium(III) compounds. The element was discovered in 1863 by Ferdinand Reich (1799-1882) and Hieronymus Richter (1824-90). 

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