|Lung and Sinus Tumours in Rats After Inhalation or Topical Injection of Ce-144 and Treatment with Different Cofactors
|Published: Open access to everyone
|Dr. Michele Morin
|BIOLOGICAL SAMPLE AVAILABLE
|Purpose: To determine the cancer risks from beta-emitters after inhalation or, to simulate uptake from wounds, after injection of radioactive particles into the leg, the sinus or the maxillary bone and to compare the results with those obtained from alpha-emitters, in some experiments, also in the presence of cofactors.
Status: 1975 - 1978 terminated; data in ERAD
Treatment: Inhalation in a single session, intramuscular injection or injection into the maxillary, the sinus or the tooth of Ce-144 trichloride (or Ce-141 oxide or trichloride adjusted to pH 5 for inhalation).
Dosimetry: Mean initial activity inhaled or injected, measurement of lung burden 3 days after exposure, determination of organ activities at autopsies; dose calculated from these data
Endpoints: Life-span study (spontaneous death) with macroscopic/microscopic pathology.
Animal: Male Sprague-Dawley SPF rats aged 3 months (one group 5 days); controls see 02.01
Results: Inhalation of Ce-144 chloride at doses from 3 to 62 Gy caused a dose-dependent reduction in survival and an increase in lung cancers. When stable Ce was added to retard the dissolving of the Ce hydroxide in the alveoli, the number of lung cancers increased significantly after doses from 15-54 Gy. The cancers observed were mainly of the epidermoid type, but 1 osteosarcoma and 6 angiosarcoma were also observed.
Inhalation of the oxide Ce-141 (a -emitter of much lower energy than Ce-144 and the oxide of which is very insoluble in lung) caused lung cancers and sarcoma in the dose range of 0.1-22 Gy. One third of the lung cancers were of the epidermoid type or adenocarcinomas, two third were bronchiolo-alveolar carcinomas. These experiments demonstrated the (possibly synergistic) relation between radioactivity and masse and, especially, the influence of the spatio-temporal distribution of the exposure on the histological type of lung cancers.
Local administration was performed to study the induction of osteosarcomas, the time of appearance of tumors and the efficiency of therapeutic methods used in man. The method used allowed to determine exactly the begin of the tumor development because the site of injection of the insoluble radioactive solution was known. It was found that the incidence of metastasis, occurring mainly in lung, was comparable to that seen in man.
|Link to data and details in ERA
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