Each year, over 1 million patients die from pancreatic and liver cancer worldwide. Surgery and transplantation are the only curative modalities for these cancers; however, less than 30% of patients are eligible for surgery. New treatments are needed to convert non-surgical to surgical candidates. Photodynamic therapy (PDT) is an emerging modality for the treatment of pancreatic and liver cancers. Currently, most photosensitizer drugs are being delivered through intravenous injection or oral administration, and low percentages of administered dose reaches the tumor. We have developed a Light-Activatable, Sustained-exposure Ethanol Injection Technology (LASEIT) that can improve the efficacy and safety of PDT for locally advanced, unresectable tumors. We have demonstrated that LASEIT enhances photosensitizer delivery by up to 40X and improves light propagation in the tumor. These features can significantly reduce side effects, shorten operating room turnover time, and improve PDT efficacy.