Quick scientific question (polydimethylsiloxane)

In an article from 2022 I read the following;
"...DaRT seeds were made of 6.5-mm-long stainless steel (316 LVM) tubes with an outer diameter of 0.7 mm and an inner diameter of 0.4 mm, loaded with 224Ra atoms, following an electrostatic collection process similar to that described in (31). To prevent radium detachment from the surface, the seeds were subsequently coated by a 1-mm-thick biocompatible polymer layer made from polydimethylsiloxane (PDMS-silicone adhesive, MED2-4213), which allows 220Rn atoms to be released into the tumor tissue..."

The source:
"Diffusing alpha-emitters radiation therapy in combination with temozolomide or bevacizumab in human glioblastoma multiforme xenografts" https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.888100/full (2022)

Is this polymer coating layer still being used in patient trials? I couldn't find any article so far that mentions the polydimethylsiloxane. Any sources from Alpha Tau that mentions it?