My father had 'radium needles' inserted into his neck for several days to fight his cancer. And that was way back in 1954, nearly 70 years ago. It worked for him too, at least for about 15 years till his cancer returned.
A few years after his treatment, I had 'radium needles' taped to my large toe to kill off a plantar wart. I remember having to sit in the doctor's waiting room for 3 hours while they 'worked'. I wasn't allowed to do anything else, in case they were lost. I was told they were very, very expensive.
They looked like plain silvery rods about 2-3 mm in diameter and about 1 cm long. I remember thinking they just looked like somebody had cut short bits off some nails.
IIRC the doctor said they were hollow stainless steel containers and the radium was filled into the cavity. I suppose my dad's were pretty similar in appearance to mine.