Seeing is believing with the "Atlas of Normal Roentgen Variants That May Simulate Disease", edited by the late Theodore Keats and Mark W. Anderson. Now streamlined into a more concise, portable print format, with a wealth of additional content online, this medical reference book's thousands of images capture the roentgenographic presentation of a full range of normal variants and pseudo-lesions that may resemble pathologic conditions, helping you avoid false positives.
You'd be hard pressed to find a comparable image collection in any one place online.