Photodynamic therapy (PDT) is a new selective treatment technique for (vascular) proliferative tissues, which was introduced in the late 1970s and has been rapidly developed in recent years. With the approval of the first photosensitizer Porfimer Sodium in the United States, Canada, European Union, Japan and Korea from 1993 to 1997, the research, development and application in the field of PDT have been rapidly active. In recent years, with the successful development of new photodynamic therapy drugs and the improvement of laser equipment technology, PDT has again ushered in an unprecedented development peak. Internationally, nearly a dozen new photosensitizers have been approved for marketing or are under clinical study. Meanwhile, PDT is also used for the treatment of non-tumor type diseases, such as acanthosis, psoriasis, erythema, rheumatoid arthritis, fundus macular degeneration, and post-angioplasty restenosis. Photodynamic therapy is a new disease treatment based on the interaction of light, photosensitizers and oxygen, and the research of photosensitizers (photodynamic therapy drugs) is the key to the prospect of photodynamic therapy. Photosensitizers are special chemicals whose basic role is to transfer energy, which can absorb photons and be excited, and quickly transfer the absorbed light energy to another group of molecules, so that they are excited and the photosensitizer itself returns to the ground state. Photosensitizers can be dynamically concentrated in abnormal growth tissues (such as tumors, age-related macular degeneration, macular nevus, acanthosis, etc.), and they can produce reactive oxygen species such as singlet oxygen under the excitation of appropriate wavelengths of light, which can destroy target cells. PDT has been gradually improved with the development of photosensitizer research. What are the indications for photodynamic therapy? 1. Pre-cancerous skin diseases and skin malignancies, gaze keratosis (AKs), Bowen\”s disease (BD), basal cell carcinoma (BCC), squamous carcinoma (SCC). , Kaposi\”s sarcoma (KS), mycosis fungoides (MF). 2, PDT treatment of non-malignant tumor skin diseases, warts, vascular malformations, acne vulgaris, viral skin diseases, sebaceous hyperplasia, photorejuvenation (PDT-IPL, PDT with blue light) The advantages of photodynamic therapy are different from the traditional surgery, radiotherapy and chemotherapy three major means of treatment of tumors, it has selective target tissue and the degree of damage. PDT-IPL (PDT with blue light) has the advantage of being selective to the target tissue and the degree of damage, which can reduce the damage to normal tissue. Compared with conventional treatments such as surgery, chemotherapy and radiotherapy, photodynamic therapy has the following important advantages: (1) minimal trauma: with the help of optical fiber, endoscope and other interventional techniques, laser can be guided deep into the body for treatment, avoiding the trauma and pain caused by open-chest and open-abdomen surgeries. (2) Low toxicity: The photosensitive drug entering the tissue will trigger photodynamic reaction and 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. (3) Good selectivity: The main target of photodynamic therapy is the lesion tissue in the light irradiated area, and the damage to the normal tissue around the lesion is slight, this selective killing effect is difficult to achieve by many other treatments. (4) 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 restricted. (5) Repeatable treatment: Cancer cells are not resistant to photosensitive drugs, and patients will not increase toxic reactions due to multiple photodynamic treatments, so treatment can be repeated. (6) Palliative treatment: For patients with advanced tumors, or tumor patients 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. (7) It can improve the efficacy with surgery: for some tumors, surgical resection first, followed by photodynamic therapy can further destroy residual cancer cells, reduce the chance of recurrence and improve the thoroughness of surgery; for some other tumors, it is possible to do photodynamic therapy first to shrink the tumor before resection, which can expand the indications for surgery and improve the success rate of surgery. (8) Eliminate hidden cancer lesions: clinically, some tumors, such as bladder metastatic cell carcinoma, may have scattered microscopic cancer nests invisible to the naked eye outside the main lesion, and conventional treatment can only remove the main lesion, but it can do nothing for the hidden cancer nests. (9) Protecting appearance and important organ functions: For skin cancer of face, oral cancer, penile cancer, cervical cancer, retinoblastoma, etc., the application of photodynamic therapy may effectively kill cancer tissues while minimizing the damage to epithelial structure and collagen scaffold of the developing organ, so that the appearance will be less affected and the organ shape and normal physiological functions will be kept intact after wound healing. The application of photodynamic therapy is very promising. In recent years, great progress has been made at home and abroad in the application of photodynamic therapy for the treatment of non-tumor diseases, such as acanthosis, nevus, fundus macular degeneration, rheumatoid arthritis, psoriasis, atherosclerotic plaques, and post-angioplasty restenosis. In particular, the new topical photosensitizer’s – Aminoketovaleric acid hydrochloride (Ella, ALA) was marketed and creatively used for the treatment of condyloma acuminata, pushing the photodynamic treatment of condyloma acuminata with Aminoketovaleric acid hydrochloride to clinical research for the first time in the international arena. The results of clinical trials showed that ALA-photodynamic therapy for intra-urethral warts had a 95% wart clearance rate and was well tolerated by patients; for extra-urethral warts, the wart clearance rate was 98.42%. The recurrence rate is only 10.77%. At the same time, the safety is high: no scars, the incidence of adverse reactions is only 7.67%. Experts agree that Ira photodynamic therapy will be the first choice for intra-urethral warts and the first-line treatment for extra-urethral warts. How is photodynamic therapy performed? The photodynamic treatment process is simple, its main operational steps are dressing and light, and the treatment process is painless. 1, first by the health care provider to configure a fresh solution to be used during treatment. 2.Wet dress the affected area with fresh medicine solution for 3 hours and seal the package according to the specific situation. 3, photodynamic irradiation of the lesion local, irradiation time is usually 20 minutes. 4. When the course of treatment is over the warts become flaky and dry and fall off on their own. The Urethral warts ALA-PDT treatment before and after who is suitable to receive photodynamic therapy? 1, special anatomical site treatment: such as warts occurring in the urethral orifice, urethra, vulva around the opening of the glands of patients. 2, sensitive parts of the treatment: such as warts occurring in the mucous membrane parts of the patient. 3. Patients who have relapsed after trying other treatments. 4. Patients who are being treated for the first time. 5. Patients with single or small number of warts, i.e. patients with concentrated latent lesions. 6, after the treatment of other traditional therapies to consolidate the effect of treatment to prevent the recurrence of warts.