PhotodynamicTherapy (PDT) is a new drug-device combination technology that utilizes photosensitizer and light for disease diagnosis and treatment. When the light of specific wavelength irradiates the photosensitizer absorbed by the lesion tissues, it can be excited, and the photosensitizer in the excited state can transfer the energy to the surrounding oxygen molecules, generating the monomorphic oxygen with strong cytotoxicity, which leads to oxidative damage of cells, resulting in the damage or even death of the lesion cells and tissues. It is a new method of tumor treatment following surgery, radiotherapy and chemotherapy. Photodynamic therapy has the following advantages: ①, targeting – it has selective treatment effect on the tumor and slight damage to the normal tissues around the lesion. For skin cancer, oral cancer, penile cancer, cervical cancer, retinoblastoma and so on, the application of photodynamic therapy can effectively kill cancerous tissues and minimize the damage to epithelial structure and collagen scaffolds of the pathogenic organs, so as to maintain the integrity of organ shape and normal physiological function after wound healing. The wound can maintain the integrity of organ shape and normal physiological function after healing. ③ It can eliminate hidden cancer foci – in some tumors in clinic, there may be scattered tiny cancer nests that are invisible to the naked eye outside the main foci, and photodynamic therapy can eliminate all the tiny lesions that may exist, thus greatly reducing the chances of tumor recurrence. Low toxicity – only when the photodynamic drugs entering the tissues reach a certain concentration and are irradiated by a sufficient amount of light will trigger the phototoxic reaction to kill the tumor cells. The part of human body not irradiated by light does not produce such reaction, and organs and tissues in other parts of human body are not damaged, nor does it affect hematopoietic function. ⑤. Wide anti-cancer spectrum, no drug resistance – Cancer cells are not resistant to photosensitive drugs, and photosensitizers are not selective in their affinity and retention to tumors. Patients will also not have increased toxic reaction due to multiple photodynamic therapy, thus the treatment can be repeated. (6) Palliative treatment – For certain tumor patients (such as tumor patients who cannot accept surgery, radiotherapy or chemotherapy, and patients with advanced tumors), photodynamic therapy is an effective palliative treatment that can reduce pain and prolong life. (7) Improve the curative effect with surgery – For some tumors, surgical resection followed by photodynamic therapy can further eliminate the residual cancer cells, reduce the chance of recurrence and improve the thoroughness of surgery. (8) Shortening of hospitalization time – Due to the slight trauma and low toxic side effects of photodynamic therapy, patients recover rapidly after treatment and hospitalization time is shortened. Indications of photodynamic therapy 1, digestive tract tumors – esophageal cancer, pancreatic cancer, gastric cancer, colon cancer, rectal cancer, liver cancer, etc. 2, Respiratory tract tumors – tracheal and bronchial tumors, malignant mesothelioma. 3.Genitourinary tumors: bladder cancer, prostate cancer, uterine adenocarcinoma, penile cancer, cervical cancer, etc. 4, Superficial tumors – skin cancer and precancerous lesions. 5.Head and neck tumors–nasopharyngeal cancer, oral cancer, tongue cancer, glioma, etc. 6.Palliative treatment, treatment of residual and recurrent tumors or improvement of obstructive symptoms, etc.