How are scans best used to monitor mets. in bone?

  How can disease that is in bone and on chest wall be best monitored?  What can x-rays show that bone scans don't and vis-versa? Are some tests better at seeing lytic and others at seeing blastic disease? At what point are  tests other than  bone scans and xray reasonable, especially to monitor tumor on chest wall?
   Please explain how a bone scans can show "stable disease" while a comparison of one x-ray to a previous x-ray  over the same 15 months earlier can  show "disease progression" to a radiologist and  "bone healing" to an oncologist.  My doctor says a bone scan is the most sensitive test but I am wondering if bone scans should really be the only test-to-be-believed.  If bone scans sense higher than normal metabolic activity, then how could it have missed the changes in my hip that appeared on x-rays 15 months apart? In what way does bone healing appear different from cancer's progression on an x ray? Are there experts in interpreting dignostic scans to whom one can send  scans and x- ray to for second opinion/ review? I'm dealing with stage 4 (after what was diagnoised as DCIS) with know met. to chest wall and bone (ribs, hip, vertebra, femur, pelvis). I've been on zometa, zoladex, and aramadex for 15 months now.