The use of photodynamic therapy for the treatment of malignant tumors is a new technology in tumor treatment that has emerged and evolved in the last 20 years. Since its introduction in the late 1970s, PDCT has made remarkable achievements in the clinical treatment of tumors. PDCT has unique and irreplaceable advantages compared with other traditional treatments for tumors, such as surgery, chemotherapy and radiotherapy. The so-called PDCT therapy refers to the intravenous injection of photosensitizing compounds such as hematoporphyrin (HP) or other hematoporphyrin derivatives (HPD) into tumor patients as photosensitizing agents, and then irradiating the tumor site with laser of appropriate wavelength within 48-72h after the injection to make the HP and HPD gathered in the tumor site emit fluorescence, so as to complete the diagnosis and localization of malignant tumor, and then using laser of appropriate wavelength to make the HP and HPD emit fluorescence. Then, the appropriate wavelength laser is used to irradiate the HP and HPD to generate oxygen molecules with high oxidation capacity to destroy the tumor cells and cause necrosis of malignant tumor tissues, thus achieving the purpose of tumor treatment. PDCT therapy has the characteristics of relatively selective killing of local primary and recurrent tumor cells, no or less damage to healthy tissues, and less toxic side effects, so it is especially suitable for patients who are old and weak, cannot be operated or need intravenous chemotherapy, especially for those advanced tumor patients whose traditional treatment methods are ineffective or dangerous. Of course, due to the objective conditions, PDCT therapy still has one or more problems. For example, the application of PDCT therapy for deep tumor treatment is limited by the shallow depth of light penetration. In addition, phototoxicity is also a problem that has not been completely solved. Therefore, it is very important to improve the effectiveness of PDCT therapy and reduce the toxic side effects. In 1981, our country developed the domestic HPD photosensitizer which can be used in PDCT therapy for tumor treatment, which played a great role in promoting the research of PDCT therapy for tumor treatment in our country later, so that our country has achieved promising results in this research. Indications: Photodynamic therapy is a new technology for the treatment of many kinds of solid malignant tumors and some benign lesions, which has some important advantages and can precisely compensate for some shortcomings of conventional means. Therefore, by accurately grasping the uniqueness of this technology and integrating it rationally into the overall design of comprehensive tumor treatment, doctors in hospitals with the conditions may be able to obtain better results by taking into account both tumor control and improvement of survival quality. For some patients whose cancers are in early stage but cannot or are not suitable for conventional treatment such as surgery due to the dysfunction of important organs such as heart, lung and kidney, it is more likely to obtain cure through photodynamic therapy. It is mainly used clinically for tumors of the cavity, cavity, body surface and certain abnormal growths. The main indications are: esophageal cancer, cardia cancer, bronchopulmonary cancer, bladder cancer, nasopharyngeal cancer, etc. The indications are: stomach cancer, oral cavity cancer, larynx cancer, bronchus cancer, lung cancer, bile duct cancer, liver cancer, cervical cancer, colorectal cancer, skin cancer, breast cancer, brain cancer, vaginal cancer, penile cancer, brain glioblastoma, etc. Photodynamic therapy is also suitable for the following skin cancers: basal cell carcinoma, squamous epithelial carcinoma, malignant melanoma, Bowen’s disease, eczema-like skin cancer, carcinoma in situ, etc. It is especially suitable for patients who are old or have contraindications to surgery, chemotherapy or radiotherapy, or patients who have relapsed after surgery or radiotherapy. Contraindications: The main adverse effect of photodynamic therapy is photoallergic reaction. For patients using a photosensitizer such as PHOTOFRIN, the patient must avoid direct sunlight or strong light exposure for a month or so after the injection of the photosensitizer to prevent unnecessary skin photoallergic reactions due to the slow clearance process of the residual photosensitizer in the skin. Once a photoallergic reaction occurs, it is manifested by a localized skin rash or blister, which can be quickly relieved by routine treatment. In addition, within a few days after the treatment, patients may have localized temporary reactive edema at the treatment site, which may also cause some discomfort, such as pain in the chest, back or abdomen, dyspnea in patients with bronchial cancer, dysphagia in patients with esophageal cancer, frequent urination and hematuria in patients with bladder cancer, and other possible side effects such as fever and constipation, all of which vary depending on the specific lesion and condition being treated. All of them vary depending on the specific lesion and condition, but they are generally not serious and of short duration, and can be relieved by conventional treatment. In general, the toxic side effects of photodynamic therapy can be said to be very mild, and photosensitivity of the skin can be prevented by avoiding light, and photodynamic therapy does not impair the function of the hematopoietic and immune systems. All these are very beneficial for the patient’s treatment and life. All in all, the toxic side effects of photodynamic therapy can be said to be minimal, and most importantly, it does not impair the function of the hematopoietic and immune systems, which is something that has to be seriously considered in chemotherapy and radiotherapy. Adverse reactions: The main adverse reaction to photodynamic therapy is photoallergic reaction. For patients using a photosensitizer such as PHOTOFRIN, the patient must avoid direct sunlight or strong light exposure for a month or so after the injection of the photosensitizer to prevent unnecessary skin photoallergic reactions due to the slow clearance process of the residual photosensitizer in the skin. Once a photoallergic reaction occurs, it is manifested by a localized skin rash or blister, which can be quickly relieved by routine treatment. In addition, within a few days after the treatment, patients may have localized temporary reactive edema at the treatment site, which may also cause some discomfort, such as pain in the chest, back or abdomen, dyspnea in patients with bronchial cancer, dysphagia in patients with esophageal cancer, frequent urination and hematuria in patients with bladder cancer, and other possible side effects such as fever and constipation, all of which vary depending on the specific lesion and condition being treated. All of them vary depending on the specific lesion and condition, but they are generally not serious and of short duration, and can be relieved by conventional treatment. In general, the toxic side effects of photodynamic therapy can be said to be very mild, and photosensitivity of the skin can be prevented by avoiding light, and photodynamic therapy does not impair the function of the hematopoietic and immune systems. All these are very beneficial for the patient’s treatment and life. All in all, the toxic side effects of photodynamic therapy can be said to be minimal, and most importantly, it does not damage the function of the hematopoietic and immune systems, which is something that has to be seriously considered in chemotherapy and radiotherapy. Technical route: The local tumor tissue is selectively injected with photosensitizer and stored in it. After subsequent local irradiation with appropriate wavelength light by direct application or indirect endoscopy, the photosensitizer is activated and the photosensitizing effect is produced to achieve the effect of killing tumor cells. Quality control measures: Firstly, the distribution of photosensitizer is managed. In the absence of light, whether used systemically or locally, the toxicity of the photosensitizer in the dark is negligible. The target cells and normal cells target photoreceptor concentration ratio appears to be different, after reaching the action target. The second step is that the light source is directed at the affected location. The duration of action and the energy of the light source must be adjusted according to the depth of the action location, which is sufficient to activate the photoreceptor energy. In the third step, the activation of the photoreceptor stimulates a photochemical reaction that produces reactive oxygen species (ROS) causing a cytotoxic effect. Such an action causes necrosis of the target cells as well as tissue destruction, but not to the extent that normal cells are affected. [1] [2] [5] An effective photodynamic therapy depends on the ability to accumulate photoreceptors in the target cells and to metabolize them rapidly in normal cells. Efficacy criteria and assessment methods: The first is the administration of the photoreceptor distribution. In the absence of light, the toxicity of the photoreceptor in the dark is negligible, whether used systemically or locally. After the target cells and normal cells target photoreceptor concentration ratio appears to be different, after reaching the action target. The second step is that the light source is directed at the affected location. The duration of action and the energy of the light source must be adjusted according to the depth of the action location, which is sufficient to activate the photoreceptor energy. In the third step, the activation of the photoreceptor stimulates a photochemical reaction that produces reactive oxygen species (ROS) causing a cytotoxic effect. Such an action causes necrosis of the target cells as well as tissue destruction, but not to the extent that normal cells are affected. An effective photodynamic therapy depends on the ability to accumulate photoreceptors in the target cells (i.e., tumor cells) and to metabolize them rapidly in normal cells. Comparison with other medical technologies for the treatment of the same disease (in terms of risk, efficacy, cost, course of treatment, etc.) Photodynamic therapy, as a new technology for tumor treatment, has many important advantages compared with conventional means such as surgery, chemotherapy and radiotherapy, and is increasingly showing an important role in the comprehensive treatment of tumors. 1.Oropharyngeal cancer: early oral cancer and nasopharyngeal cancer are 75%-100% efficient; 2.Esophageal cancer: eradicate early cancer; effectively improve the obstruction of progressive esophageal cancer; treat cervical esophageal cancer very effectively; treat submucosal disseminated esophageal cancer; for esophageal cancer that grows into the lumen and has been stented, it can eliminate the tumor in the lumen; 3.Barrett esophagus: not only can effectively eliminate Barrett’s esophageal epithelium, but also treat the epithelium of the esophagus. esophageal epithelium, and can treat early esophageal adenocarcinoma; 4.Lung cancer: for early bronchial cancer, the cure rate is 90%, for progressive obstructive bronchial cancer, the improvement rate is 85%; 5.Gastric cancer: for early gastric cancer, the eradication rate is 85%; effectively improve the symptoms of progressive gastric cancer; 6.Bladder cancer: eradication of carcinoma in situ, the efficiency rate for progressive cancer is 71%; other effective treatment of cancer: colorectal cancer, bile duct cancer It is especially suitable for cholangiocarcinoma of the hilar region, pancreatic cancer and pot belly cancer, abdominal cavity tumor, pleural peritoneal mesothelioma, liver cancer, brain tumor, genitourinary tract cancer; advantages: compared with conventional treatments such as surgery, chemotherapy and radiotherapy, photodynamic therapy has the following important advantages: very little trauma with the help of optical fiber, endoscope and other interventional techniques, the laser can be guided to the deep part of the body for treatment, avoiding the trauma and pain caused by open-heart and open-heart surgery. It avoids the trauma and pain caused by open-heart and open-heart surgery. The photodynamic yao that enters the tissue with low toxicity will trigger phototoxic reaction to kill tumor cells only when it reaches a certain concentration and is irradiated by sufficient amount of light, which is a local treatment method. The part of human body that is not irradiated by light does not produce such reaction, and the organs and tissues in other parts of human body are not damaged, nor does it affect the hematopoietic function, so the toxic side effects of photodynamic therapy are very low. The main target of photodynamic therapy is the diseased tissue in the irradiated area, and the damage to the normal tissues around the lesion is slight, and this selective killing effect is difficult to be achieved by many other treatments. Good applicability Photodynamic therapy is effective for different cell types of cancer tissues and has a wide range of applicability; while the sensitivity of different cell types of cancer tissues to radiotherapy and chemotherapy can vary greatly and the application is limited. Repeatable Cancer cells are not resistant to photosensitive yao, and patients will not increase toxic reactions due to multiple photodynamic treatments, so repeatable treatment is possible. Palliative treatment For patients with advanced tumors or those who cannot receive surgery due to advanced age, cardiopulmonary, hepatic and renal insufficiency or hemophilia, photodynamic therapy is a palliative treatment that can effectively relieve pain, improve quality of life and prolong life. It can improve the efficacy of surgery. For some tumors, surgical resection first and then photodynamic therapy can further destroy the residual cancer cells, reduce the chance of recurrence and improve the thoroughness of surgery; for other tumors, it is possible to do photodynamic therapy first to make the tumor shrink before resection, which can expand the indications for surgery and improve the success rate of surgery. Some tumors, such as bladder metastatic cell carcinoma, may have scattered microscopic cancer nests invisible to the naked eye outside of the main lesion, and conventional treatment can only remove the main lesion, but can do nothing about the hidden cancer nests. For skin cancer of face, oral cancer, penile cancer, cervical cancer, retinoblastoma, etc., the application of photodynamic therapy has the potential to effectively kill cancerous tissues while minimizing damage to the epithelial structure and collagen scaffold of the developing organ, so that the appearance is less affected and the appearance of the organ and normal physiological functions are kept intact after the wound heals. The treatment time is short because the trauma of photodynamic therapy is mild and the toxic side effects are low, the patient recovers quickly after treatment and the hospitalization time is shortened.