ViewRay this morning announced that Penn State Health has entered a master agreement to purchase up to four MRIdian systems with the immediate order of one system and the ability to order an additional three systems in the future, Piper Jaffray analyst Matt O'Brien tells investors in a research note. This news follows an announcement last Thursday of an MRIdian order from Stanford Health Care, adds the analyst. He views these orders as "incremental positives" and further evidence of the "unique capabilities" of the MRIdian system. O'Brien reiterates an Overweight rating on ViewRay with a $6 price target.