Hematoporphyrin Derivative (HPD) is a medical term used to describe a photosensitizing substance used in photodynamic therapy. However, there are several synonyms for this compound. First off, Photofrin is a commonly used term that refers to HPD. It is the brand name for this photosensitizing agent. In addition, DHE (dihematoporphyrin ether) is another synonym used to describe HPD. This derivative shares similar properties and uses in photodynamic therapy. Finally, Porfimer sodium is yet another term that can be used interchangeably with HPD. These synonyms help facilitate a clearer understanding of the compound and its applications in medical research and treatment.