I've had brain tumor surgery and 28 treatments of radiation since march .i've always ran low bp. in the pass week it's been running high 155/94.is thi?

Depends: It depends on what medications or your stress levels or both. If you are taking medications like steroids(think decadron) it's possible that a medication is causing this. Chemotherapeutics to treat cancers can also cause this. In rare cases a brain bleed can lead to increased blood pressure, and slow heart rates(Cushing's reflex). Nonetheless let your doctors know about this.