Since 2006, Beijing Jenerator always supply high power grid tube for mecical MRI and PET as RF power amplifier,
which is produced for decades in China. They have stable parameter and muture technolgoy.
The cost of performance is absolutely high.
The electron tube used for medical MRI and PET application is mainly 3CPX1500A7, 3CX10000A7 and 4CX5000A.