A system for perfusing a localized site within a body includes a catheter assembly having a venous access line that is adapted to deliver perfusate to the localized site, a venous or arterial drainage line adapted to drain perfusate from the localized site, and an occlusion device adapted to prevent some or substantially all physiological blood flow between the localized site and the systemic circulation of the body during and in the course of perfusing and draining perfusate to and from the localized site. The system may include a blood circuit associated with the catheter assembly to facilitate blood conditioning for use as the perfusate, in the course of a controlled perfusion and/or drainage of untreated, treated, or inactivated treated blood to and from the localized site. A delivery machine may control the blood circuit and catheter assembly in order to both deliver perfusate to, and drain some or all perfusate from, the localized site in a manner that provides perfusate to substantially only the localized site.
