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Cerebral ventriculography is a medical procedure developed by Walter Dandy , and designed to enable visualization of structures inside the skull .
 person: Walter Dandy
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Walter Dandy 
Answer:
 person: Walter Dandy