Optical phantom materials for near infrared laser photocoagulation studies

Background and Objective: Phantoms were developed that simulate tissue with dynamic and static optical properties with which to study the effects of l aser irradiation. Study Design/Materials and Methods: Albumen, agar, and an absorbing dye (Na phthol Green) were combined to form a phantom with heat sensitive optical p roperties to mimic tissue response. The optical properties of this phantom were measured by using the added absorber technique. A polyacrylamide phant om with static optical properties was designed with the equivalent values o f mu(a) and mu(s)' by combining appropriate concentrations of Naphthol Gree n and Intralipid-10%. Results: The absorption and reduced scattering coefficient of the phantoms were 0.50 +/- 0.04 cm(-1) and 2.67 +/- 0.07 cm(-1) respectively, in the nat ive state at 805 nm. In the coagulated state, the absorption and scattering coefficient were 0.7 +/- 0.1 cm(-1) and 13.1 +/- 0.5 cm(-1) respectively. Conclusion: Two phantoms with dynamic or static optical properties were dev eloped with properties similar to tissue. They may be used in future studie s of opto-thermal effects in tissues. (C) 1999 Wiley-Liss, Inc.