In vivo determination of the lutetium texaphyrin concentration in canine using fluorescence technique

Presents a simple method to quantitatively estimate the concentration of photodynamic therapy (PDT) photosensitizer Lutetium texaphyrin (Lutrin (R)) in vivo. The technique is relative and does not require difficult absolute measurements of fluorescence. The method quantitatively relates the area of the normalized fluorescence peak of Lutrin (R) at 740 nm to the drug concentration in mg/kg. The relation is used to estimate Lutrin (R) concentration in vivo. The method has been verified by detecting concentration of Lutrin (R) during intraperitoneal photodynamic therapy (IF PDT) in canine. The authors demonstrated that the procedure is very sensitive, and reliably detects presence of the photosensitizer, giving an order of magnitude estimate of its concentration. The relative distribution of Lutrin (R) among different organs (kidney, liver, mesentery, bowel and prostate) was evaluated as well. The presented method can be used in human trials in vivo without further modifications