if the pdf was generated from the cad package then it is most likely vector data.
in that case :
1) open the pdf file in Adobe illustrator : explode the group and remove the clipping are'as. remove all the crap you don't want.
2) make sure only one layer exists
3) export as DXF with correct scale.
4) import in a PCB CAM tool like camtastic
5) patch up the donuts to pads and set the track widths correct.
6) export gerber
7) decompile into netlist/pcb data

push into Altium PCB editor
yep it can be done . i have done it. but it requires some effort, time, ptience , and a bunch of tools (Illustrator and Altium Designer)