Data collected from the clinicaltrials.gov website show different photosensitizers (y-axis) and their respective administration routes (x-axis). Each dot in the plot represents a clinical trial that is Active (not recruiting), Enrolling by invitation, Recruiting, or Not yet recruiting. Our summary indicates a majority of photosensitizers are currently administered intravenously in the clinic, with the exception of 5-ALA. In the plot, clinical trials that are Suspended, Terminated, Completed, Withdrawn, or have Unknown status were not included. Photosensitizers include 5-aminolevulinic acid (5-ALA or Gliolan®), porfimer sodium (Photofrin®), WST-11 (TOOKAD® Soluble), verteporfin-based PS (e.g., Visudyne®, HS-201), ruthenium-based PS (TLD1433), temoporfin (tetra[m-hydroxyphenyl]chlorin, m-THPC, or Foscan®), and 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH or Photochlor®). Routes of administration include intravenous (IV, administration within or into a vein or veins), topical (TOPIC, administration to a particular spot on the outer surface of the body), oral (PO, administration to or by way of the mouth), intratumor (IT, administration within a tumor), and intravesical (I-VESIC, administration within the bladder).