Safety and Feasibility Study of Methylene Blue Photodynamic Therapy to Sterilize Deep Tissue Abscess Cavities

Administration of 1 mg/mL methylene blue to the abscess cavity, followed by a 10 minute incubation interval. After this incubation interval, the methylene blue solution will be aspirated from the cavity and flushed twice with sterile saline.

The abscess cavity will be filled with sterile 1% Intralipid solution to gently distend the cavity and, through efficient light scattering, to homogenize the light dose to the walls of the cavity. After laser illumination, the Intralipid will be aspirated from the cavity.

A sterile, FDA-approved optical fiber will be advanced to the approximate center of the abscess cavity via the drainage catheter under image guidance. Following laser illumination, the fiber will be withdrawn.

Laser illumination will be delivered via the optical fiber for a duration of 5 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

Laser illumination will be delivered via the optical fiber for a duration of 10 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

Laser illumination will be delivered via the optical fiber for a duration of 15 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

Laser illumination will be delivered via the optical fiber for a duration of 20 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

Laser illumination will be delivered via the optical fiber for a duration of 25 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

Laser illumination will be delivered via the optical fiber for a duration of 30 minutes. The fluence rate will be set such that the maximum fluence rate at the abscess wall is 20 mW/cm2.

A fiber-optic probe that has undergone high-level disinfection will be advanced through the drainage catheter/needle in order to make gentle contact with the wall of the cavity. Low-intensity white light will be delivered by a tungsten halogen lamp by a single fiber within the probe, and detected by eight other fibers within the probe. Following this, low-power laser light will be delivered by a fiber-coupled laser diode at 640 nm in order to excite methylene blue fluorescence. Emitted fluorescence will similarly be collected by the eight detection fibers contained within the probe. Upon completion of these measurements, the fiber-optic probe will be withdrawn, gently wiped with sterile gauze, and returned to the procedure cart.