Indocyanine green (ICG), when in free form in a liquid, can form stable nanoparticle structures or colloidal solution, while changing its spectroscopic properties. In the work, the aggregation degree and the average size of nanoparticles depending on the concentration of a colloidal solution of indocyanine green (ICG NPs) in the form of J-aggregates were investigated by various methods based on light scattering. The size of nanoparticles is an important parameter from the point of view of clinical application, because the technique of intravenous administration of drugs, in order to avoid microvascular thrombosis and embolism, provides dosage forms with inclusions of individual molecules or their clusters, not exceeding 500 nm diameter. In turn, small nanoparticles less than 30 nm lead to prolonged circulation of the drug in the body with an increased possibility of permeation into cells of healthy tissue. In the course of studies, it was found that an increase in the concentration of ICG NPs in the solution leads to an increase in the average size of spontaneously formed J-aggregates, which, in turn, leads to a decrease in the absorption coefficient in the aggregates. Presumably, this phenomenon, i.e. the established nonlinear dependence of the J-aggregate absorption on its size, can be explained by the formation of absorption centers on the J-aggregate surface in the form of mobile surface molecules. The threshold range of ICG molecule concentration was determined, at which there is a transition from aggregation with an increase in size with a slow addition of ICG J-aggregate molecules in height to a rapid addition in width.

Treatment of poorly-pigmented tumors of small sizes can be carried out using photodynamic therapy (PDT). The material for the analysis was data on 112 patients. We used data from the Belarusian Cancer Registry, medical records of patients with clinically diagnosed choroid melanoma (C69.3 according to ICD-10) for the period 2013–2021. The size and level of blood flow in the tumors were assessed using an ultrasound machine with a doppler attachment. PDT was carried out using a «UPL PDT» semiconductor laser (Lemt, Republic of Belarus, λ=661 nm) with a light spot diameter of 1 to 3 mm for 60 s per field with a light dose of 50 J/cm2. The entire surface of the tumor was exposed to the action, with the fields “tiled”, from the periphery to the top of the tumor, with overlapping fields. Tumor pigmentation was assessed visually. To evaluate the treatment outcome, the general group of patients was divided into three subgroups according to thickness and basal diameter. Group I – 40 (35.7%) patients, with an average tumor thickness of 1.4±0.2 mm, basal diameter – 5.8±1.5 mm. II – 51 (45.5%) patients, with an average tumor thickness of 2.3 ± 0.3 mm, basal diameter – 7.9 ± 1.5 mm. III – 21 (18.8%) patients. The mean value of the tumor thickness was 3.8±0.4 mm, the basal diameter was 9.8±1.4 mm. After PDT in the general group (n=112), 29 (25.9%) patients had complete tumor resorption, and 83 (74.1%) patients had stabilization. The eyeball was saved in 107 (95.5%) patients. Continued growth and relapse were recorded in 34 patients: 25 (22.3%) and 9 (8.0%), respectively. In 29 (85.3%) patients, the eyeball was preserved after treatment of relapse and continued growth. 5 (4.5%) enucleations were performed. Adjusted one-year cumulative survival was 100%, 3-year and 5-year 95.8±2.4%, 93.7±3.1%, respectively

Extramammary Paget’s disease (EMPD) is a rare tumor that predominantly affects the skin containing apocrine glands. Due to insufficient data on the effectiveness of different methods, there is no single therapeutic approach to the treatment of patients with EMPD and their subsequent management. The use of surgical methods, laser therapy and local cytotoxic drugs has a number of limitations. The advantages of using photodynamic therapy (PDT) in EMPD are the absence of systemic toxicity, non-invasiveness, selectivity of action, the absence of carcinogenic potential, the possibility of conducting several courses of treatment, and good cosmetic results. In our review, we analyzed those published in 2000-2022 data on the results of PDT treatment of 114 patients with EMPD. As a result of treatment, complete regression of tumor foci was achieved in 40% of patients. Most authors note that PDT is more effective for small areas (up to 4 cm2).

Photodynamic therapy (PDT) is one of the most effective treatments for basal cell skin cancer (BCC). As the incidence rate of BCC is increasing worldwide, interest in developing new methods for diagnosing and treating this disease, taking into account long-term cosmetic results, is growing. The review article presents the results of domestic and foreign studies on the treatment of BCC with PDT. The presented results of studies from various domestic and foreign clinics indicate the high efficiency of independent PDT and a combination of PDT with other treatment methods. PDT is proposed to be used in combination with surgical methods and radiation therapy, immunomodulating and chemotherapeutic agents, and inhibitors of molecules involved in the carcinogenic process. These new strategies open the way to increasing the effectiveness of treatment and prevention of BCC. Moreover, in all studies, the safety of this non-invasive treatment, a low level of adverse reactions during therapy, good tolerance for the patient and excellent cosmetic treatment results are noted. The guidelines currently being developed in Europe and the United States provide consistent expert advice that reflects current published evidence of treatment outcomes for BCC using PDT. Moreover, the recommendations emphasize that the treatment plan for patients with “difficult to treat” BCC should be discussed at an interdisciplinary oncological council.

The article describes a clinical example of timely, safe and effective photodynamic therapy (PDT) in a patient diagnosed with human papillomavirus (HPV) CIN I-associated cervical cancer after ineffective vaccination with 4-valent Gardasil vaccine. Clinical case demonstrates the low effectiveness of HPV vaccination in patients with established HPV infection. In this patient, the lack of adequate treatment for about 1.5 years led to the development of HPV associated CIN I of the cervix. Center for Laser and Photodynamic Diagnostics and Therapy of Tumors and MRI P.A. Herzen, the patient underwent a course of antiviral PDT with the achievement of complete regression of dysplasia and complete eradication of HPV viruses. The patient tolerated the treatment well, without complications. The period of relapse-free follow-up is 19 months.