An apparatus, comprising: an in vivo apparatus comprising: a flexible shaft having a proximal end, a distal end, and a length sufficient to access a patient's renal artery relative to a percutaneous access location; and an energy guide apparatus provided at the distal end of the shaft and dimensioned for deployment in a renal artery, the energy guide apparatus configured to generate a rotating energy beacon including a rotating magnetic field and a rotating beam of acoustic energy; an ex vivo apparatus comprising: an arrangement configured to localize the energy guide apparatus within the renal artery; and an energy source configured to direct ablative energy to target tissue located a predetermined distance from the localized energy guide apparatus, the target tissue comprising perivascular renal nerve tissue; wherein the localizing arrangement is configured to: sense the rotating magnetic field at a first location defining a first reference frame; detect the rotating beam of acoustic energy at a second location defining a second reference frame; and localize the energy guide apparatus using at least the sensed rotating magnetic field and the detected rotating beam of acoustic energy. an in vivo apparatus comprising: a flexible shaft having a proximal end, a distal end, and a length sufficient to access a patient's renal artery relative to a percutaneous access location; and an energy guide apparatus provided at the distal end of the shaft and dimensioned for deployment in a renal artery, the energy guide apparatus configured to generate a rotating energy beacon including a rotating magnetic field and a rotating beam of acoustic energy; a flexible shaft having a proximal end, a distal end, and a length sufficient to access a patient's renal artery relative to a percutaneous access location; and an energy guide apparatus provided at the distal end of the shaft and dimensioned for deployment in a renal artery, the energy guide apparatus configured to generate a rotating energy beacon including a rotating magnetic field and a rotating beam of acoustic energy; an ex vivo apparatus comprising: an arrangement configured to localize the energy guide apparatus within the renal artery; and an energy source configured to direct ablative energy to target tissue located a predetermined distance from the localized energy guide apparatus, the target tissue comprising perivascular renal nerve tissue; wherein the localizing arrangement is configured to: sense the rotating magnetic field at a first location defining a first reference frame; detect the rotating beam of acoustic energy at a second location defining a second reference frame; and localize the energy guide apparatus using at least the sensed rotating magnetic field and the detected rotating beam of acoustic energy. an arrangement configured to localize the energy guide apparatus within the renal artery; and an energy source configured to direct ablative energy to target tissue located a predetermined distance from the localized energy guide apparatus, the target tissue comprising perivascular renal nerve tissue; wherein the localizing arrangement is configured to: sense the rotating magnetic field at a first location defining a first reference frame; detect the rotating beam of acoustic energy at a second location defining a second reference frame; and localize the energy guide apparatus using at least the sensed rotating magnetic field and the detected rotating beam of acoustic energy. sense the rotating magnetic field at a first location defining a first reference frame; detect the rotating beam of acoustic energy at a second location defining a second reference frame; and localize the energy guide apparatus using at least the sensed rotating magnetic field and the detected rotating beam of acoustic energy.