The Charles University Teaching Hospital in Prague - Motol started to treat patients with retinoblastoma by means of brachytherapy after obtaining the permission to use closed source of ionizing radiation in the beginning of the year 2003. The applicator containing ruthenium (106Ru) emitting mostly the beta radiation was chosen. Half-life is 369 days and the nominal activity of the source is 21.1 MBq. The applicator is placed in pláce for one to several days according to the prominence of the tumor and actual activity of the source. Duration of the application is calculated with a speciál program. In the year 2003, three patients with retinoblastoma were treated. In one čase bilateral involvement was determined, and the brachytherapy was ušed for treatment of both eyes. The next patient was treated twice; one treatment followed the other with different localization of the applicator because of too large basis of the tumor. In 2003, altogether the brachytherapy was ušed for treatment of retinoblastoma fivc times. In all cascs, the combined treatment (chemo reduction, teletherapy, transpupillary thermotherapy, or cryotherapy) was performed. One eyeball was enucleated because of severe post-radiation retinopathy, the second one for persisting tractional retinal detachment. In remaining cases no serious complications or progression of the malignancy were observed.

        Key words: brachytherapy, retinoblastoma, ionizing radiation, radioisotope, ruthenium, closed source of ionizing radiation, ocular applicator