One problem of radiation and chemotherapy is the ravaging effect it can have on healthy, noncancerous cells. In the last few years, one treatment has gained attention as a viable alternative for some forms of esophageal and early-stage lung cancer: photodynamic therapy. Photodynamic therapy (PDT) involves the use of molecules called photosensitizers, which, when exposed to a light source, transfer energy to surrounding oxygen molecules and produce compounds that damage vital cell components, eventually causing cell death. These compounds tend to accumulate in abnormal or proliferating cells -- particularly the cells of new vessels that feed growing tumors. This enables surgeons to isolate cancer cells and selectively destroy them.