Radiotoxicity

1.3.4 Radiotoxicity

Radiotoxic effects are reported from the old generation of glass and resin
microspheres, by leaching of the radioisotope from the particles, which can result in
pancytopenia [63]. The new generation of spheres showed no such leaching. These
spheres were used for the first time in the well-known dog experiments by Wollner et
al. [64], showing that the animals survived a liver dose of up to 350 Gy. However, at
such exceedingly high (and clinically unrealistic) doses, sequelae related to cirrhosis
would be likely to become a significant problem. Even 800 Gy to the whole liver of
rabbits was tolerated [65]. These experiments showed that internal radiotherapy using
non-leaking microspheres can be performed safely with high doses. In patients in
which doses up to 100 Gy were directed to the liver, the hepatic toxicity of the
treatment appears to be low, as is shown by the liver enzyme levels [2].
Gastroduodenal ulceration has been reported as a complication of intra-hepatic arterial
glass microsphere therapy, and this may be related to migration of microspheres to
organs outside the liver, caused by the high density of the spheres [15,29,66,67].
Radiation pneumonitis was documented in a patient in which the lung dose was
greater than 30 Gy, whereas most patients received a lung dose of less than 20 Gy
[11,68].