1425
The authors discussed their experience in investigating 20 patients with maxillary malignant tumors using routine x - ray studies and MR - tomography , and 13 patients , investigated in the same way plus CT .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 None