6492
Tl - 201 uptake ratio of the right ventricle , which represents the ratio of total counts of the right ventricle to counts of the administered dose of Tl - 201 , was higher in COPD , especially in pulmonary emphysema and B type COPD by Burrows classification than in controls .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None