1
2
3
4
5
6
7
Subject (ZB):
“...PET (positron emission tomography)...”
8
Subject (ZB):
“...anthropogenic emissions...”
9
10
11
12
Subject (ZB):
“...emission...”
13
14
15
16
Subject (ZB):
“...emission...”
17
18
Subject (ZB):
“...SPECT (single photon emission computer tomography)...”
19
20