Ghostbusters: The Video Game

The way to get this achievement is similar to what the other membesr suggest for the solution, however there are a few steps missing. I'll be as detailed as possible.

In the children's reading room (checkpoint is "Story Hour"), equip your paragoggles and head to the first door on your left. Attempt to open the door, there will be furniture behind it. Equip your proton pack and blast away the blockade, the door should swing open the rest of the way. Re-equip your goggles and head into the far back corner of the room where there is a chair and a teddy bear resting on it. Your PK meter should be going off the scale right now. Once you approach close enough a ghost will vanish from the spot. Look down on the ground with your goggles. There are children footprints. I scanned a few of them just in case. Follow the footprints, you should cross an ectoplasmic children's hopscotch game. Continue to follow the foot steps to the reading corner. Watch the teddybear do its dance, once the child ghost disappears again, the achievement will unlock.

On the library mission you will enter a children's book section. There is a room in the corner with a large window that is blocked from entering behind the door. Break the window and break a table behind that window and everything else in that room behind the window to gain entry. Scan the teddy bear on the chair in the corner with your PKE meter to gain the achievement.

What i did was what Rx861 said but it didn't work. so i was walking back to the barricaded room but i went into the room beside it (after breaking in the room then going to the reading corner, that's when i went into the room with the tv in it) and i got the achievement.