Thorotrast

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Thorotrast

Thorotrast and Umbrathor are the trade names for an X-ray contrast medium that was launched on the market in 1929 and is based on a stabilized 25% colloidal suspension of thorium dioxide . It was mainly used as a contrast medium for angiography until it was banned in the mid-1950s . The high atomic number and the high atomic mass of thorium cause a strong absorption of X-rays by this contrast medium. No immediate side effects in patients could be observed with the first applications before the market launch. It was known that thorium is radioactive, but the very long-lived isotope 232 Th - natural thorium consists 100 percent of this isotope with a half-life of 1.405 · 10 10 years - was classified as harmless. This was a fatal error, as it turned out many years later.

toxicology

The colloidal thorium dioxide accumulates in the reticulohistiocytic system and can lead to cancer there due to locally increased radiation exposure . There are clear associations between Thorotrast and bile duct carcinoma , and angiosarcoma or hemangioendothelioma of the liver , otherwise very rare malignant tumors , can be induced by Thorotrast. Carcinomas of the sinuses following administration of Thorotrast have also been described. Typically, the diseases appear 30 to 35 years after exposure . The biological half-life - the time until 50 percent of the administered thorium dioxide is excreted from the body - is about 400 years.

application

In most cases, the contrast medium was injected undiluted intravenously or intraarterially in amounts of approx. 25 ml . The amount of thorium brought into the body was about 5 grams.

Thorotrast in the media

In 2002 the Danish director and surgeon Nils Malmros made a biographical film about his father Richard Malmros under the German title “In Wissen der Truth” (orig. At kende sandheden , English. Facing the Truth ). In the award-winning film, the dilemma of Malmros' father is made clear, either to use Thorotrast, which is ideally suited as a contrast medium for diagnostics - with the long-term side effects known to him - or the only alternative available at the time (Per-Abrodil = diethanolamine-3,5- diiodpyridone-4-acetic acid with iodine as the absorbing component), which showed significant immediate side effects, provided a significantly poorer image contrast and was also difficult to obtain during the Second World War.

Alternatives

Instead of Thorotrast, much improved aromatic iodine derivatives are used today as intravenous or intraarterial X-ray contrast media.

literature

  • John Abbatt: History of the Use and Toxicity of Thorotrast in Environmental Research , 18/1979, pp. 6-12.
  • WE Strole, J. Wittenberg: Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 15-1981. In: N Engl J Med 304, 1981, pp. 893-899.
  • K. Wegener, H. Wesch, H. Kampmann: Investigations into human thorotrastosis. Tissue concentrations of 232-Th and late effects in 13 autopsy cases. In: Virchows Arch A Pathol Anat Histol. 371/1976, pp. 131-143.
  • JL Poggio, DM Nagorney, AG Nascimento et al .: Surgical treatment of adult primary hepatic sarcoma. In: Br J Surg . 87/2000, pp. 1500-1505.
  • A. Spiethoff, H. Wesch, K. Wegener et al: Translocation of Thorotrast in the body. In: Radiat Res. 138/1994, pp. 409-414.
  • T. Mori, C. Kido, K. Fukutomi et al., Summary of entire Japanese thorotrast follow-up study: updated 1998. In: Radiat Res. 152/1999, pp. 84-87.
  • CW Mays: Alpha-particle-induced cancer in humans. In: Health Phys. 55/1988, pp. 637-652.
  • JS da Horta: Late effects of thorotrast on the liver and spleen, and their efferent lymph nodes. In: Ann NY Acad Sci. 145/1967, pp. 676-699.
  • JD Abbatt: History of the use and toxicity of thorotrast. In: Environ Res. 18/1979, pp. 6-12.
  • CF Tessmer, JP Chang: Thorotrast localization by light and electron microscopy. In: Ann NY Acad Sci. 145/1967, pp. 545-575.
  • H. Irie, W. Mori: Long term effects of thorium dioxide (thorotrast) administration on human liver. Ultrastructural localization of thorium dioxide in human liver by analytical electron microscopy. In: Acta Pathol Jpn. 34/1984, pp. 221-228.
  • JA Terzakis, SC Sommers, RW Snyder and others: X-ray microanalysis of hepatic thorium depositions. In: Arch Pathol. 98/1974, pp. 241-242.
  • A. Odegaard, EM Ophus, AM Larsen: Identification of thorium dioxide in human liver cells by electron microscopic X-ray microanalysis. In: J Clin Pathol . 31/1978, pp. 893-896.

Individual evidence

  1. ↑ a b A. M. Krasinskas: Redistribution of thorotrast into a liver allograft several years following transplantation: a case report. In: Modern Pathology . 17/2004, pp. 117-120.
  2. ^ Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 15-1981. In: The New England Journal of Medicine . Volume 304, Number 15, April 1981, pp. 893-899, doi: 10.1056 / NEJM198104093041508 , PMID 6259526 .