Photodynamic therapy (PDT) is a new treatment technique that selectively destroys lesions through photodynamic reactions by combining photosensitizers and corresponding light sources, and is another new treatment being researched and developed after traditional tumor therapies such as surgery, radiotherapy, chemotherapy and immunotherapy. Since the trial of PDT with 5-aminoketovaleric acid in 1990, it has been widely used in the field of dermatology to treat skin tumors such as actinic keratosis, basal cell carcinoma, squamous cell carcinoma, Bowen’s disease and other benign proliferative diseases with satisfactory results. Its unique advantages such as safety and high efficiency have made it one of the popular fields of research, development and application in China and abroad. First, the process of ALA photodynamic therapy fresh ALA for fresh preparation, prepared into a solution or cream for the affected area, put on the affected area and wait for a certain period of time for laser light, and finally the lesion is cleared. Second, ALA treatment of condyloma acuminata The pathogen of condyloma acuminata is HPV, 08 years German Heidelberg University Professor Ruschhoff therefore won the Nobel Prize in medicine, due to his discovery to make human cervical cancer a preventable disease, but also the first preventable tumor in human history, he found that the vast majority of women’s cervical cancer is caused by high-risk HPV infection. (a) HPV classification HPV is divided into two categories, low-risk HPV and high-risk HPV, low-risk HPV is represented by HPV6 and HPV11, which mainly cause condyloma acuminata in the external genital area (as shown on the figure), high-risk HPV is represented by HPV16 and HPV18, which mainly cause cervical cancer and VIN, it is a relatively high carcinogenic virus. (The traditional treatment of condyloma acuminata includes freezing, laser, electrocautery, microwave and surgical excision. These treatments have some drawbacks, such as the treatment of urethral condyloma acuminata it can cause urethral stricture and recurrence, the recurrence rate is very high, because the urethral lesions are difficult to fully exposed, traditional treatment methods are difficult to reach, so the recurrence rate is very high, repeated treatment can cause adhesions, scars, adhesion ulcers, for the treatment of condyloma acuminata bring a lot of inconvenience. (C) case study A new treatment method is needed clinically, and ALA-PDT is used to treat urethral condyloma acuminata with good results. It has treated thousands of patients from the beginning to now, with a recurrence rate of about 6% and an effective rate (complete healing rate) of more than 95%. Its side effects are pain, especially when illuminated, and generally no anesthetic but local anesthesia is available. There is no scarring, necrosis or urethral stricture. The acromegaly of the urethra, after three photodynamic treatments, the urethral orifice becomes smooth and the urethral mucosa can be seen through the urethroscope are smooth. It shows that ALA-PDT is a simple, effective, relatively safe, low recurrence rate and efficacious method for the treatment of acromegaly. Some patients have very narrow urethral orifices, so it is difficult to insert cotton swabs for medication, and it is also difficult to put in fiber optics, so photodynamic therapy has really solved a big clinical problem. The actual fact is that you can find a lot of people who have been in the business for more than a year, and then you have to do a urethroscopic examination to check the depth of the urethra and the depth of the warts, and if you can use the medication, you need to locate the medication, and you need to locate the fiber optic irradiation, so as to ensure the effectiveness of the treatment and reduce the recurrence rate. The deepest part of the patient’s warts is at the inner urethra, the junction of the urethra and the bladder. The warts are found in the center of the urethroscope i.e. the center of the urethral orifice after urethroscopic examination, in case of water the warts float in the center, this is rare, so for patients with more than one year of disease are recommended to do urethroscopic examination first to make sure there are no warts inside before treatment. The actual fact is that you can find a number of things that you can do to help you to get the most out of your time. The actual fact is that there is no drug that can directly kill the HPV virus, but there are some other methods to make the warts and viruses necrotic and fall off with the necrosis of the cells, which requires the participation of the immunity of the human body to be able to completely remove the HPV. The study on the treatment mechanism of photodynamic therapy is really effective, the patient after photodynamic therapy, i.e. warts after ALA-PDT, different time points to take material for histopathological examination and ultramicroscopic examination (electron microscopic observation). It was found that before treatment, it had a lot of keratin-forming cells with excavated cells, which are signs of HPV virus infection. After 1 hour of treatment a large infiltration of neutrophils can be seen, followed by neutrophil lymphocytes wandering toward the epidermis, and at 3 hours epidermal degeneration and necrosis can be seen, and at 5 hours structural destruction, degeneration and necrosis of cells in the place of HPV infection can be seen. Ultramicro-pathological changes, observed under transmission electron microscopy, can be seen in HPV-infected cells before treatment as double nucleoli, and double nucleoli means that the cells are metabolizing vigorously. At 1 hour of treatment, the first site of involvement was the mitochondria, which disappeared, some of which were crinkled, some disappeared, and some swollen with tennis racket-like changes. at 3 hours, apoptotic changes could be seen, and the wreath-like structure was typical of apoptotic changes. at 5 hours, the entire tissue structure of the cells disappeared, degenerated, and necrosed. After the study, it was concluded that ALA-PDT is effective in the treatment of condyloma acuminatum through both apoptosis and necrosis.