May one wear a medical cap that treats cancer with electrical fields on Shabbos?

Rav Yitzchok Zilberstein ruled that the Optune medical cap used to heal glioblastoma (a type of head tumor) may be used on Shabbos because it lengthens patients’ lives, emphasizing that those who avoid its use on Shabbos are mistaken.

As for its battery pack, it can be taken out wherever there is a proper eiruv, he said.

According to the company that produces the device, nearly half the people who used Optune in addition to chemotherapy were alive at two years, compared to only 31 percent of people on chemotherapy alone.