Bismuth retention

There exist no reliable criteria to define Bi absorption, but possible criteria are blood and plasma levels or daily urinary excretion. Blood levels of Bi > 300 pg L are diminished by hemodialysis in vitro, and this may be explained by there being two different forms of bismuth, namely soluble and bound (Allain 1976). Monitoring of Bi treatments should also include the determination of Bi in whole blood as well as in plasma (Rao and Feldman 1990). Bismuth administered subcutaneously to rats as BiClj is deposited in the kidneys, which were found to contain > 50% of the accessible pool of bismuth. Retention in the kidneys was diminished, while levels in liver and 12 other tissues were augmented (Jad-wiga et al. 1979). 

The elimination kinetics of bismuth have been described as a three-compartment model with half-lives of 3.5 minutes, 0.25 hour, and 3.2 hours (Slikkerveer and de Wolff 1989). Biological half-times in human have also been reported whole body retention 5 days, kidney 6 days, liver 15 days, spleen 10 days, and bone 13.3 days (IRCP 1960, Fowler and Wouk 1986). 

Yao Z, Garmestani K, Wong K J, et al. (2001). Comparative cellular catabolism and retention of astatine-, bismuth-, and lead-radiolabeled internalizing monoclonal antibody. /. Nucl. Med. 42 1538-1544. 

Radiopharmaceuticals for use in therapy should have a long retention time and be highly selective. Low-energy beta emitting isotopes are used (e.g., iodine ( I)). Some high-energy beta emitters (yttrium ( °Y), phosphorus ( P)) and alpha emitters (bismuth ( Bi)) are also used. 

Conservative approach was used in the design of SVBR-75/100 (lead-bismuth fast reactor of 75-100 MW equivalent electric power, depending on steam parameters), which provides for the retention of operation parameters of the primary and secondary circuits at the levels that have been already mastered in practice, for the use of qualified fuel and structural materials and proven technical solutions for the equipment components and reactor installation scheme. This approach assures that technological approaches implemented in other reactor installations, first of all, the propulsion reactors of nuclear submarines, have been to the maximum possible extent inherited by the SVBR-75/100 design. Adhering to this approach reduces the terms, scope and costs of necessary R D and investment risk, and secures high reliability and safety of the reactor installation. 

Use of bismuth oxide as an inexpensive additive to the zinc electrodes to improve the capacity retention and the cycle life of the cells. ... 

---