Selective incorporation of111In-labeled PHOTOFRIN? by glioma tissuein vivo

Publisher Website
Google Scholar
Abstract
The use of PHOTOFRIN™ for photodynamic therapy of human gliomas has been studied by i.v. administration and laser photosensitization. Defining the uptake of PHOTOFRIN™ in the patient's tumor in comparison with the surrounding normal brain tissue is highly desirable for patient selection and study ofin vivo kinetics. We utilized a non-invasive approach to the detection of PHOTOFRIN™ uptake in brain tumors with111In-oxine radiolabeled PHOTOFRIN™ and external imaging and quantitation using a gamma camera. Biodistribution of111In-labeled PHOTOFRIN™ in 13 organs was determined in four dogs and 15 mice with gliomas.99mTc-DTPA was used as a control for nonspecific uptake. The greatest concentration of111In-PHOTOFRIN™ in the brain tumor occurred at 24 hours post i.v. administration. The brain tumor PHOTOFRIN™ uptake was seven times greater than that of normal brain. The decreased blood background at 72 hours made this the optimum time for imaging. Specific tumor tissue uptake of111In-PHOTOFRIN™ occurred, well beyond that resulting from blood-brain-barrier (BBB) breakdown.