[Therapeutic effect of 125I-103Pd hybrid radioactive seeds on pulmonary carcinomas in BALB/c-nu mice].

Objective: To prepared (125)I-(103)Pd hybrid radioactive seeds and to explore their therapeutic effect on pulmonary carcinomas.

Methods: The (125)I-(103)Pd hybrid radioactive seeds were prepared by a chemical method of step-by-step coat plating. Pulmonary adenocarcinoma of GLC-82 cells and pulmonary large cell carcinoma of H460 cells were cultured in vitro and then were exposed directly to (125)I, (103)Pd and (125)I-(103)Pd seeds for 48 hours to observe the killing effects of radiation. GLC-82 and H460 tumor models were established and 20 mice chosen randomly for each model. For each tumor model, there were 4 groups (n = 5 each). Then (125)I-(103)Pd, (125)I, (103)Pd and nonradioactive seeds were implanted into the tumors. Tumor sizes and weights of mice were measured and recorded every 5 days for a 2-month observation.

Results: The (125)I-(103)Pd hybrid radioactive seeds were prepared successfully. After a 48-hour radiation from radioactive seeds, the GLC-82 cells within one particulate around (125)I, (103)Pd or (125)I-(103)Pd seeds were inhibited so as to become swollen and transfiguring. The H460 cells around (125)I seeds showed no obvious abnormality while those within one particulate around (103)Pd or (125)I-(103)Pd seeds were much fewer. No mouse died during the observation period. The radioactive seeds could inhibit the tumors. The radiotherapeutic effects were similar in two tumor modes: (125)I-(103)Pd seeds > (103)Pd seeds ≈ (125)I seeds > non-radioactive seeds. H460 tumors grew much faster than GLC-82 tumors. Meanwhile the seeds with the same nuclide were much more effective for GLC-82 tumors than for H460 tumors.

Conclusion: The (125)I-(103)Pd hybrid radioactive seeds are clinically applicable due to their effective inhibitions of tumor growth.