...this is Madame Curie killing herself
by discovering RADIUM.
The Big Bang Theory Season 6, Episode 4
Madam Curie's discovery of RADIUM
turned out to have great potential...
The Big Bang Theory Season 1, Episode 2
Don't you worry about the residual RADIUM
from the luminous dials?
The Big Bang Theory Season 2, Episode 1
♪ Of a RADIUM in a lead jar
The Big Bang Theory Season 12, Episode 23
bathed in the glow of their love
and the RADIUM
The Big Bang Theory Season 5, Episode 16