[Use of ruthenuim 106 in retinoblastoma treatment]. / Vyuzití Ru106 pro lécbu retinoblastomu.

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 place 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 special program. In the year 2003, three patients with retinoblastoma were treated. In one case bilateral involvement was determined, and the brachytherapy was used 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 used for treatment of retinoblastoma five times. In all cases, the combined treatment (chemoreduction, 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.

In vivo thermoluminescence dosimetry for total body irradiation.

An improvement in the clinical results obtained using total body irradiation (TBI) with photon beams requires precise TBI treatment planning, reproducible irradiation, precise in vivo dosimetry, accurate documentation and careful evaluation. In vivo dosimetry using LiF Harshaw TLD-100 chips was used during the TBI treatments performed in our department. The results of in vivo thermoluminescence dosimetry (TLD) show that using TLD measurements and interactive adjustment of some treatment parameters based on these measurements, like monitor unit calculations, lung shielding thickness and patient positioning, it is possible to achieve high precision in absorbed dose delivery (less than 0.5%) as well as in homogeneity of irradiation (less than 6%).