@article{buckley96a, author = {L. A. Buckley and S. A. Prahl and S. L. Jacques}, title = {Method and Apparatus for Determination of Psoralen Concentrations in Biological Tissues}, journal = {United States Patent. No.\ 5,522,868}, year = {1996}, abstract = {Levels of psoralen concentration in a biological detection target are determined so that an appropriate UVA light dose of PUVA therapy can be delivered to a biological treatment target. The appropriate therapy is determined by the product of the UVA light dose and psoralen concentration level. After determination of a baseline optical autofluoresence signal from the detection target, a first dosage of psoralen (preferably 8-methoxypsoralen [8-MOP]) is administered. Thereafter, the detection target is irradiated under the same conditions as the pre-psoralen irradiation. Then, the optical return from the psoralen-treated detection target is analyzed. A computer (86) compares the pre-psoralen optical return and psoralen-treated optical return to calculate a real time determination of the concentration level of psoralen in the treatment target. Then, then knowing the precise psoralen concentration level, a UV dosage level required to achieve the desired PUVA therapy can be precisely determined and applied to the treatment target. In some embodiments, the detection target is the treatment target and in vivo real time psoralen concentration is determined. Various forms of applicators (52, 452, 552, 652, 752) are provided for differing types of targets. Each applicator is mounted on an optical fiber bundle (54). In some embodiments, the same optical fiber bundle (54) is employed to transmit the irradiation and optical return signals in the psoralen concentration determination, as well as to transmit the UVA for the PUVA therapy.}, }