Question: Maryland Subscriber Answer: Regarding version 17.1's retroactive changes to modifier indicators for nuclear medicine edits, the column 1 codes involved all describe radiopharmaceutical therapy. The column 2 codes describe radiopharmaceutical imaging, uptake, and tumor localization, along with patency test code 78291 (Peritoneal-venous shunt patency test [e.g., for LeVeen, Denver shunt]). The change is retroactive to Jan. 1, 2011, so you may resubmit claims denied because of the edits for dates of service between Jan. 1 and March 31.