Depends on how gung ho you are.
Mettlers Essentials of Nuclear medicine OR Nuclear Medicine: the requisites, by thrall is excellent. Both are very readable.
These books are about 450pp, but just focus on the chapters related to the bread and butter stuff: V/Q scans, Bone Scans, Renal, Thyroid. Read a little about PET and the physics behind nucs.
While Squires is a good book for the basics of radiology, I don't know if the depth of coverage of nucs is adequate for a one month rotation.