-Comparison of the old and recent films

(2)

(4)

(1)

(3)

When using comparison films one should hang old PA(1)to the far left then new PA(2) to the left of the midline then new lateral(3) to the right of the midline followed by old lateral(4).  For PACS many radiologists use two monitors and view the PA and lateral, then compare the new PA to old PA, and finally the new lateral to the old lateral.