Reflectance feedback control of photocoagulation in vivo.

OBJECTIVE

The objective of this research was to build a real-time feedback system that controlled lesion size. Two-dimensional reflectance images were acquired with a charge-coupled device camera during irradiation, and argon laser exposure was ended when parameters of the image reached prespecified values.

METHODS

The real-time feedback control system was tested by creating lesions at different power levels in pigmented rabbits. Laser exposure time was controlled by monitoring the central reflectance.

RESULTS

Results of feedback-controlled lesions formed in vivo in pigmented rabbits are presented. An ability to produce uniform lesions despite variation in tissue absorption or changes in laser power is demonstrated.

CONCLUSIONS

Reflectance control of photocoagulation is possible; incorporation of feedback during photocoagulation has numerous therapeutic and safety benefits over current ballistic delivery.