Sentence:  A fifth principle and a constant challenge is the blanket proscription by radiologists (and x-ray technicians) to “<WSD>pump and dump</WSD>” breast milk for 24 to 48 hours when radiocontrast agents are used. 
Meaning of the word marked with <WSD> tags:  To use a breast pump and then discard the milk, typically because one has had an infection, or been drinking alcohol.