358672
A multileaf collimator ( MLC ) is a device made up of individual " leaves " of a high atomic numbered material , usually tungsten , that can move independently in and out of the path of a particle beam in order to block it .
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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:  
Answer:
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