Existing drawbacks of the radionuclide therapy planning may lead to the excessive irradiation of the healthy organs and tissues that is associated with the development of deterministic and stochastic effects. In some cases absorbed dose in region of interest (lesion) can be lower than prescribed therapeutic dose. That reduces the effectiveness of radionuclide therapy and reduces survival rate of patients. These problems are associated with administration of the fixed activity of radionuclide in radiopharmaceutical, or administration of activity normalized per unit of body mass or body surface. That approach does not allow assessing absorbed doses in lesions or healthy tissues for individual patients. Report of International Commission on Radiation Units and Measurements 96 «Dosimetry-guided radiopharmaceutical therapy», published in 2021, presents modern approaches for the dosimetric planning of radionuclide therapy based on the individualized assessment of absorbed doses in organs and tissues. This study was aimed at the analysis of proposed in Report 96 methods of classification of irradiated regions, organs and tissues based on example of radionuclide therapy with ¹⁷⁷Lu-DOTATATE. Proposed terms and definitions are harmonized with previous reports of International Commission on Radiation Units and Measurements on external radiation therapy. Terms and definitions analyzed in the current study will be used in the following studies aimed at the development of the requirements on dosimetric planning of radionuclide therapy.

At the present time three most common approaches are used for the planning of the radionuclide therapy: administration of the fixed activity of radionuclide in radiopharmaceutical, or administration of activity normalized per unit of body mass or body surface. That may lead to significant deviations between the prescribed and real absorbed doses in healthy organs and tissues. These deviations are associated with differences in biodistribution and pharmacokinetics of radiopharmaceutical between models and real patients. That does not allow individual planning of the treatment course for each patient since data on the accumulated activity in source regions and organs at risk is limited and uncertainty is too high for the calculation of absorbed doses. Improvements in the reliability of the absorbed dose calculation can be achieved through the use of different imaging modalities (diagnostic nuclear medicine) for the quantitative assessment of accumulated activity of radionuclides in organs and tissues and distribution of radiopharmaceutical in healthy tissues. Planning of radionuclide therapy should be personalized. The current study was aimed at the analysis of the approaches the dosimetry-based planning of radionuclide therapy presented in the Report of International Commission on Radiation Units and Measurements 96 «Dosimetry-guided radiopharmaceutical therapy», differentiated based on the possibilities of the nuclear medicine departments, including examples of levels of planning for most common radiopharmaceuticals. The results of analysis indicated that most optimal approach for Russian clinical practice is to transit to the requirements of planning level 1: to calculate and report administered activity considering patient body mass, type and stage of disease was well as prescribed clinical task. Requirements of planning level 2 are currently impossible to implement nation-wide, except for several nuclear medicine research facilities. Additionally, it is necessary to focus on the development of the methods of estimation of absorbed doses in major delineable organs.

INTRODUCTION: According to the literature, ⁶⁸Ga-FAPI-04 has receptor specificity for malignant neoplasms with overexpression of the fibroblast activation protein and is used to visualize various types of neoplasms, in particular head and neck cancer, gastrointestinal tract, lung, breast cancer with a high contrast ratio of the tumor to the background, and may possibly become an alternative to ¹⁸F-FDG.

OBJECTIVE: The results of the first experience of using PET/CT with ⁶⁸Ga-FAPI-04 in Russia.

MATERIALS AND METHODS: A comparative analysis of the results of ⁶⁸Ga-FAPI-04 and ¹⁸F-FDG PET/CTs with an interval of 1–3 days was carried out in 13 patients (four women and nine men) with various oncological diseases, examined from February to December 2021 in Granov Russian Research Center of Radiology and Surgical Technologies.

RESULTS: In all 13 patients, it was possible to identify both primary tumors and their metastases with different tracer uptake. ⁶⁸Ga-FAPI PET/CT compared with ¹⁸F-FDG PET/CT revealed more metastatic foci (135 vs 127) predominantly in the liver, peritoneum, mesentery, omentum, and brain due to low background uptake in these organs. In our observation, foci of increased ⁶⁸Ga-FAPI-04 uptake localized in non-enlarged retroperitoneal lymph nodes in two patients. Also, in two patients with bone metastases from bladder cancer and stomach cancer, one false positive and one false negative result was obtained with ⁶⁸Ga-FAPI-04.

DISCUSSION: The high uptake of ⁶⁸Ga-FAPI-04 in the tumor makes it a promising tracer for many types of cancer, especially in cases, where conventional ¹⁸F-FDG PET/CT faces limitations due to its pharmacokinetics. At the same time, PET/CT with ⁶⁸Ga-FAPI-04, aimed at visualizing the tumor microenvironment, may have a higher sensitivity in detecting small lesions due to the predominance of stroma in them. ⁶⁸Ga-FAPI showed better results in detecting both lytic and osteoblastic bone metastases compared to ¹⁸F-FDG.

CONCLUSION: ⁶⁸Ga-FAPI is a promising tracer for molecular imaging of most malignant neoplasms and requires further study. ⁶⁸Ga-FAPI-04 can become an addition or a full-fledged solution when other tracers have limitations.

INTRODUCTION: Follow-up of patients with pancreatic neuroendocrine tumors (p-NETs) remains little studied and relevant. The role of tumor markers as indicators of recurrence, as well as the relationship between the prevalence of the disease in ⁶⁸Ga-DOTATATE PET/CT and levels of tumor markers, has been studied in a few publications.

OBJECTIVE: To determine the significance of markers and visualization methods in the follow-up of patients with p-NETs.

MATERIALS AND METHODS: ⁶⁸Ga-DOTATATE PET/CT was performed in 73 patients diagnosed with pancreatic NET: 57 patients (78%) were previously treated, 16 patients (22%) underwent primary staging. The levels of serotonin and chromogranin-A (CgA) were studied at the time of PET/CT and at the onset of the disease. CT and MRI were performed within 2 months before PET/CT. Statistics: Spearman’s coefficient was used for correlations. To determine the levels of markers at which it is recommended to enroll ⁶⁸Ga-DOTATATE PET/CT, a ROC-analysis was performed. The result of the ROC-analysis is presented with a 95% confidence interval.

RESULTS: CT and MRI revealed metastases in 45 patients (61.6%), PET/CT revealed foci in 56 patients (76.7%), of which 13 patients had metastases of other anatomical locations, which were not previously detected. Sensitivity of ⁶⁸Ga-DOTATATE PET/CT to pancreatic NET is 94.8%, specificity is 93.3%. In ROC-analysis, the area under the curve was 0.8 for serotonin (CI95% 0.676–0.924), for CgA 0.81 (CI95% 0.695–0.925). A weak relationship was revealed between the degree of oncomarkers increase and the number of foci: for serotonin r=0.32 (p<0.05), for CgA r=0.298 (p<0.05). No correlation was found between the number of foci and the tumor proliferative activity index (Ki67). Also, for all foci localizations, there was no dependence of SUV max on the levels of markers and Ki67.

DISCUSSION: In our study, ⁶⁸Ga-DOTATATE PET/CT revealed more metastases than routine methods, due to this, the treatment plan and the volume of surgical interventions were adjusted. An increase in the levels of tumor markers highly likely indicates a relapse of the disease. However, the low Spearman correlation coefficient between the number of foci and the levels of serotonin and CgA does not allow us to assume the prevalence of the tumor process by the degree of this rise. In addition, no significant relationship was found between the prevalence of the tumor and the levels of the studied tumor markers.

CONCLUSION: ⁶⁸Ga-DOTATATE PET/CT has higher accuracy in the diagnosis of p-NETs than routine imaging methods. In combination with the determination of the tumor markers levels, the probability of detecting tumor foci increases.

INTRODUCTION: Prostate cancer (PC) is the most common malignancy in men worldwide and ranks third in mortality. Improvement of the results of staging of newly detected prostate cancer is rightfully associated with the active use in clinical practice of positron emission tomography combined with computed tomography (PET/CT) with radiotracers based on prostate-specific membrane antigen (PSMA) ligands.

OBJECTIVE: The aim of the study was to determine the capabilities of PET/CT with ⁶⁸Ga-PSMA in evaluating the prevalence of newly diagnosed breast cancer in comparison with traditional imaging techniques (computed tomography, magnetic resonance imaging and bone scan) and to determine the role of this technology in the choice of treatment algorithm.

MATERIALS AND METHODS: 120 patients aged 46 to 74 years (median age 62.5 years) with histologically verified prostate cancer underwent PET/CT with ⁶⁸Ga-PSMA in our center to assess disease prevalence. The selection criteria for the study were: prostate-specific antigen (PSA) level of 5 ng/ml and above, presence of newly detected, histologically verified prostate cancer, no treatment, suspected metastatic lesion of pelvic and skeletal lymph nodes according to CT, MRI and OSG. All patients were divided into groups according to PSA level and Gleason score. Statistics: Statistical processing of the results was performed by methods of variance statistics using Statistica 10.0, GraphPad Prism 9.3.1. Wilcoxon-Mann-Whitney and Friedman tests for ANOVA were used to determine the significance of differences between comparison groups. The chi-square test with Yates correction was used to determine the reliability of intergroup differences for nominal measures (such as the presence of previous recurrences). The level of correlation was assessed using Spearman criterion.

RESULTS: PET/CT imaging analysis in addition to MRI, CT, and OSG data showed TNM staging changes in 63 of 120 patients (52.3%) due to the detection of additional foci of metastatic lesions. Change of data about local spread of tumor with increasing of TNM stage due to detection of pathological RFP accumulation in seminal vesicles in 10 of 120 patients (8.3%), without structural changes using conventional imaging methods. In 20 of 64 patients (31.3%), PET/CT revealed lesions of regional lymph nodes (N) that were not visualized by conventional imaging methods due to their small size. Metastatic lesions of distant lymph nodes (M1a) and bones (M1b) undetected by CT, MRI, and OSG were found in 27 (22.5%) and 32 (26.7%) of 120 patients, respectively. At the same time, foci of pathological accumulation of ⁶⁸Ga-PSMA in the bones without structural changes on CT were detected in 7 and 32 patients (21.8%).

DISCUSSION: One of the objectives of this study was to compare the diagnostic capabilities of standard diagnostic imaging techniques, in particular MRI, CT and Bone scan, with the hybrid technology of PET/CT with ⁶⁸Ga-PSMA to improve the accuracy of PCa staging in order to determine treatment tactics. The results demonstrate minimal superiority of PET/CT with ⁶⁸Ga-PSMA over MRI in terms of sensitivity (96% and 94%, respectively) in assessing local disease prevalence. Tumor invasion of the seminal vesicles, in most cases, was detected in patients with a Gleason score greater than 8. At the same time there was a tendency for an increase in the level of radiotracer accumulation in the tumor tissue of the seminal vesicles depending on the differentiation group of PCa. Analysis of the histological material obtained after the prostatectomy demonstrated tumorous invasion of the seminal vesicles in 26 (37.1%) out of 70 operated patients. Coincidence of histological examination results with PET/CT data was found in 22 patients, with MRI data — in 20 patients. The sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were 85%, 92%, 85%, and 92%, while the corresponding values from MRI were as follows: 77%, 88%, 77%, and 88%. Analyzing the levels of ⁶⁸Ga-PSMA uptake in the tumor tissue, we found that with increasing prostate differentiation group, there was a persistent increase in radiotracer accumulation in the prostate tumor tissue. We also evaluated the interrelation of RFP accumulation with PSA level. The patients with PCa with PSA level ≥10.0 ng/ml demonstrated high accumulation of radiotracer accumulation compared to those with PSA <10.0 ng/ml (p<0.001).

CONCLUSIONS: The use of ⁶⁸Ga-PSMA PET/CT in the staging of newly diagnosed and untreated cancers provides comprehensive information on the local, regional, and distant extent of the disease, and in some cases contributes to a change in TNM stage of the disease in a single study. The use of this method before planned surgical treatment of PCa can significantly reduce the risk of early postoperative relapse, especially in patients with a Gleason score of more than 7 and a PSA level greater than 20 ng/ml.

INTRODUCTION: Metabolic tumor volume (MTV) and Tumor lesion glycolysis (TLG) are used in ¹⁸F-fluorodeoxyglucose Positron-Emission Tomography combined with Computed Tomography (¹⁸F-FDG PET/CT) as biometric markers in whole tumor. International prognostic index (IPI) has been used during 30 years at patients with diffuse B-cell large cell lymphoma (DLBCL) for prognosis, use MTV and TLG was unknown. Our aims were to determinate the best statistical relationship between MTV, TLG and IPI in patients with DLBCL.

OBJECTIVE: Complex study of baseline volumetric parameters PET/CT with ¹⁸F-FDG at patients with DLBCL and assessment of their correlation with prognostic groups.

MATERIALS AND METHODS: Baseline ¹⁸F-FDG PET/CT performed in 31 primary patients with DLBCL and evaluated SUV_max, MTV, TMTV, TLG, TTLG at different involved anatomic zones; correlation between PET biomarkers and prognostic groups of patients.

Statistics: The research materials were subjected to statistical processing using the methods of correlation and regression analyses.

RESULTS: SUV_max mean level didn’t discerned at patients of low and high-risk groups, but TMTV has been less in favorable prognostic, than in unfavorable groups (152±3.0 sm³ vs 890±178 sm³ p<0,01); the same TTLG (1291±474 g/ml×sm³ vs 7640±2067 g/ml×sm³ , p<0.01) and IMA (6.7±0.7 vs 9.2±0.6; p<0,01). All volumetric parameters have been less at patients with supradiaphragmatic lymph nodes, than infradiaphragmatic lymph nodes and bones too. Significant positive correlation was found between the TMTV u TTLG (p=0.965; p<0,001), between TMTV, TTLG and progressive disease risk (p=0.735; p=0.747; p<0,001). The regression analysis was derived to estimate the connection PET biomarkers and progressive disease risk.

DISCUSSION: The 30-year experience of using IPI in assessing the prognosis of patients with DLBCL has shown its insufficient effectiveness in many clinical situations, and the R-IPI prognostic model has been tested on a smaller number of patients and can only be considered additionally. We studied in detail the initial volumetric parameters of patients with DLBCL in different regions of the lesion and their relationship with the level of prognosis according to the IPI criteria. Our data on large values of volumetric parameters in the infradiaphragmatic areas and bones may be related to the worse prognosis in patients with these localizations. Further broader studies of the initial volumetric biomarkers of PET in DLBCL patients will contribute to the development of approximate boundaries of specific volumetric parameters for different tumor localizations.

CONCLUSION: The results obtained showed that the baseline volumetric parameters PET/CT at patients with DLBCL have significant connection with prognostic groups of patients and can be additional factors to influence of tactics of therapy.

INTRODUCTION: During the development of CTEPH maladaptive mechanisms in the right ventricle are accompanied by disturbances in myocardial energy metabolism and perfusion. These changes can be assessed visually and quantitatively using the molecular imaging method — PET with [¹⁸F]-FDG and [¹³N]-NH₃.

OBJECTIVE: Using cardiac PET/CT investigate the relationship between perfusion and metabolism of the right ventricular myocardium and the results of other instrumental examination methods in patients with CTEPH of different severity, as well as to calculate the threshold PET values to determine the group of patients with an unfavorable clinical course of the disease.

MATERIALS AND METHODS: The study included 36 patients with a verified diagnosis of CTEPH, who were examined using a standard diagnostic protocol. Patients underwent cardiac PET/CT examinations with two radiopharmaceuticals: with [¹⁸F]-FDG to study the metabolism of the ventricular myocardium and with [¹³N]-NH₃ to assess cardiac perfusion. For each radiopharmaceutical semi-quantitative accumulation indices (SUV) and the ratio of the levels of radiopharmaceutical uptake in the right and left ventricles (SUV RV/SUV LV) were obtained. Statistics: Shapiro-Wilk test, Student’s t-test, and Mann-Whitney U-test, Pearson correlation analysis, linear regression analysis, ROC analysis.

RESULTS: The level of [¹⁸F]-FDG accumulation in the right ventricular myocardium is higher in patients with a high functional class of PH than in groups I, II (p<0.01). All indicators of SUV RV/SUV LV for [¹⁸F]-FDG demonstrate a direct linear relation-ship with the level of mean PAP (r=0.691, p<0.0001), PVR (r=0.715, p<0.0001), right ventricular size (r=0.658, p<0.0001), PASP (r=0.581, p<0.001) and inverse linear relationship with the functional parameters of the right ventricle CI (r=–0.555, p=0.001), CO (r=–0.488, p=0.005), TAPSE (r=–0.552, p<0.001), TAVS (r=–0.537, p<0.001), and SvO₂ (r=–0.666, p<0.0001). A correlation was found between the accumulation of [¹³N]-NH₃ and the main hemodynamic parameters used to assess the severity of the disease (СI, SvO₂). The threshold values of [¹⁸F]-FDG and [¹³N]-NH₃ accumulation indices have been obtained, which with high sensitivity (69.2–83.3%), specificity (68.4–94.7%) and diagnostic accuracy (0.73–0.83) make it possible to identify patients with a low cardiac index and an unfavorable prognosis.

DISCUSSION: The obtained results confirm the presence of glucose hypermetabolism in right ventricular cardiomyocytes in the development of pulmonary hypertension and the association of these metabolic changes with the severity of PH. A significant correlation was demonstrated between the accumulation of both radiopharmaceuticals in the heart and the results of other examination methods characterizing the severity of disease and the prognosis of patients with CTEPH. Using a non-invasive PET/CT procedure, threshold values of PET parameters were obtained, which in the future can be used to identify patients with an unfavorable clinical prognosis.

CONCLUSION: Cardiac PET/CT with [¹⁸F]-FDG and [¹³N]-NH₃ is a promising non-invasive imaging technique that can be used to study metabolic and perfusion changes in the right ventricular myocardium in CTEPH, as well as to identify patients with a high risk of adverse events.

INTRODUCTION: The results of studies of clinical potential of a new domestic radiopharmaceutical ¹⁷⁷Lu-DOTA-PSMA in patients with metastatic castration-resistant prostate cancer are presented in this article.

OBJECTIVE: The pharmacokinetics, safety and tolerability of radiopharmaceutical were studied. Tolerability of increasing activities — 5.0, 7.5 and 10.0 GBq was investigated.

MATERIALS AND METHODS: The study included 12 patients with metastatic castration-resistant prostate cancer, who progressed after previous treatment. The first 4 patients was treated by 5 GBq of ¹⁷⁷Lu DOTA-PSMA, the next 4 patients of the second group was treated by 7.5 GBq, and the 4 patients of the third group was treated by 10 GBq. Radiopharmacokinetics was studied by whole-body scintigraphy, SPECT/CT, blood and urine radiometry. The radiation-absorbed dose (RAD) of metastases and organs at risk was studied by clinical dosimetry. Safety assessment also was studied by hematological status. All patients was taken a complete blood count, a biochemical blood test before course of therapy treatable and during the case study.

RESULTS: Study data showed high accumulation of ¹⁷⁷Lu-DOTA-PSMA the in pathological focus, the distribution in the body conformed to the previous data of PET/CT study. Blood radiometry showed that ¹⁷⁷Lu-DOTA-PSMA rapidly excreted from the bloodstream (during the first hours after injection). Urine radiometry showed that, more than half of the injected dose was excreted during 2 days (from 34.4% to 88.8%).

DISCUSSION: During the study was solicited increasing of pain syndrome, dry mouth. Most patients had moderate myelosuppression. Changes in hematological parameters had a transistor character, the adverse event resolved without consequences in 5 week. 4^th grade of NCI CTCAE hematological toxicity criteria wasn’t identified. Serious adverse events weren’t identified too.

CONCLUSIONS: Radiopharmaceutical demonstrated high affinity for tumor tissue and safety in the clinical use. Data, which demonstrating a high potential anti-tumor efficacy of radiopharmaceutical, were obtained. Dosimetric studies showed radiation safety of work with radiopharmaceutical for the personnel.

INTRODUCTION: Peptide receptor therapy based on the ²²⁵Ac radionuclide, due to the targeted effect on tumor cells, is the most promising method of treatment for patients with generalized forms of neuroendocrine tumors and castration-resistant prostate cancer.

OBJECTIVE: The aim of the work was to evaluate the effectiveness of radioligand therapy of medicinal radiopharmaceuticals with ²²⁵Ac.

MATERIALS AND METHODS: Radioligand therapy based on ²²⁵Ac radionuclide was performed in 7 patients with generalized prostate cancer and 3 patients with neuroendocrine tumors.

RESULTS: Systemic radiation therapy with ²²⁵Ac-PSMA 617 and ²²⁵Ac-DOTATE showed its effectiveness in clinical practice — patients have a decrease in the level of accumulation of the radiopharmaceutical (RP) in pathological foci on PET-CT with ⁶⁸Ga-PSMA and ⁶⁸Ga-DOTATE; a decrease in the level of prostate-specific antigen (PSA) in the blood (for prostate cancer); reduction of manifestations of asthenic, pain and carcinoid (for neuroendocrine tumors) syndromes. Dosimetric studies make it possible to assess the biodistribution of a radiopharmaceutical drug in the body, accumulation in target organs and lesions.

CONCLUSION: The appointment of this type of treatment requires an integrated approach based on a thorough study of medical records, assessment of the receptor status of the tumor tissue, timely detection and prediction of adverse reactions.

INTRODUCTION: Skin reactions negatively affect a patient’s quality of life and may require radiation therapy premature interruption, what impairs illness control. Numerous agents determine tissue radiosensitivity, but demographic and lifestyle factors remain poorly understood. Those kind of patients herapeutic algorithm demands studies.

OBJECTIVE: Radiation-induced skin reactions (RISR) formation and severity prognostic factors determination for primary malignant skin lymphomas patients.

MATERIALS AND METHODS: 45 patients malignant T-cell skin lymphoma study, aged 38 to 82 years (29 mycosis fungoides patients, 2 lymphomatoid papulosis, 14 patients with primary anaplastic large cell skin lymphoma) received fast electrons total skin irradiation on the basis of the Federal State Institution «Russian Radiology and Surgical Technologies Scientific Center named after Academician A.M.Granov» of the Ministry of Health of the Russian Federation from 2012 to June 2022. Radiation therapy performed in the usual fractionation mode on linear electron accelerators Elekta Precise with 4–6 MeV bremsstrahlung total doses from 14 to 30 Gy (22±2.4 Gy). In order to identify the role of possible prognostic factors of skin toxicity — gender, age, body mass index (BMI), smoking status, lymphoma body surface area (BSA), the presence of concomitant diseases (diabetes mellitus and arterial hypertension) and previous chemotherapy.

Statistics: Statistical analysis was performed using the IBM SPSS Statistics v. 26 program (developed by IBM Corporation). The value of p<0.05 was considered statistically significant. Verification of the sample belonging to the normal general population was carried out using the Shapiro–Wilk criterion. Spearman's rank correlation coefficient was used for correlation analysis. The regression parameters were estimated using the least squares method.

RESULTS: The analysis revealed positive associations between the severity of RISR and predictor factors: BMI (r=0.799, p<0.01), smoking status (r=0.655, p<0.01), age (r=0.534, p<0.05), presence of diabetes mellitus (r=0.456, p<0.05), arterial hypertension (r=0.227, p<0.05), previous chemotherapy (r=0.422, p<0.01) and lymphoma body surface area (r=0.378, p<0.01). Severity of RISR scale value increase by those parameters. Negative links found between the severity of RISR and the total focal dose (SOD) of the beginning of their formation (r=–0.109, p<0.05).

CONCLUSION: Formation and severity prognostic factors for the RCC upon fast electrons total skin exposure for patients with primary malignant T-cell skin lymphomas (mycosis fungoides, lymphomatoid papulosis, primary anaplastic large cell lymphoma of the skin) were identified.

INTRODUCTION: Navigational transcranial magnetic stimulation (NTMs) is used in neurosurgical practice to identify functionally important motor areas of the brain for the purpose of safe resection of a tumor focus. At the same time, when planning radiation therapy (LT) and determining the amount of irradiation, until recently, functionally significant zones of topical representation of skeletal muscles in the cerebral cortex were not taken into account. This study evaluates the use of mapping motor areas of the cerebral cortex using NTMs when planning LT in patients with malignant gliomas affecting the motor cortex.

OBJECTIVE: To evaluate the possibilities of navigational transcranial magnetic stimulation in the pre-radiation preparation of patients with brain tumors.

MATERIALS AND METHODS: The study included 31 patients with gliomas of a high degree of malignancy who received radiation and/or chemoradiotherapy at the RSCRT from 2020 to 2022. The median follow-up was 12.1 months (3.0–24.5 months), while all patients were followed up to the control, 3-month follow-up period after the end of the course of radiation therapy, 23 patients showed up for control after 6 months (two patients died between 3-month and 6-month control).

Statistics: analysis was performed using the Statistica 10.0 software (StatSoft, Inc., USA).

RESULTS: Three out of 31 patients had improved motor function, while eight out of 31 patients had decreased motor function. Moreover, when comparing the preoperative condition with the condition during control examinations six months after radiation therapy, motor function improved in three patients, and decreased in eight. Maps of motor zones of NTMs overlapped PTV by 41.2%. The average dose of Dmean maps of NTMs was 42.3 Gy (3.7–61.1 Gy) and 37.0 Gy (3.6–55.8 Gy) with a limit of 45 Gy per motor zone. Thus, the average dose of Dmean according to the maps of the motor zones of NTMs was significantly reduced by 5.3±3.3 Gy (14.3%, p<0.05). The average dose of Dmean on NTMs cards was reduced by 4.6±3.5 Gy (12.8%, p<0.05) to 37.8 Gy. The average volume of NTMs cards receiving a dose equal to or greater than 45 Gy and 55 Gy can be significantly reduced by 11.3% and 8.4%, respectively, with dose restriction (p<0.001). Anatomical ORS (optic nerve chiasm and brain stem) were not affected in relation to the average dose of Dmean or the maximum dose with an increase in the dose to GTV.

DISCUSSION: In our study, it was shown that maps of the motor zones of NTMs can be used in the planning of LT patients with gliomas of high malignancy. To date, the primary motor cortex has not been considered as an OR in such patients. The results of the study demonstrated that the dose in relation to the maps of the motor zones of NTMs can be significantly reduced without affecting the therapeutic doses for PTV.

CONCLUSION: LT planning using NTMs motor maps can help reduce the radiation dose to the motor cortex in primary LT, although the motor cortex appears morphologically rather insensitive to LT compared to speech zones and areas of high-order cognitive processes, such as the temporal and limbic cortex.

INTRODUCTION: The incidence of rectal cancer in different countries tends to increase over the past 10 years. In the Russian Federation, the incidence of rectal cancer accounts for about 4.5% of the total oncological incidence, where stage III–IV is 25.9% and 23%, respectively. In the light of current trends, national clinical guidelines from different countries recommend starting the treatment of locally advanced rectal cancer with radiation or chemoradiotherapy. Radiation therapy is usually accompanied by radiation reactions and complications. For the last 10–15 years, hydrogel compositions have been included in the treatment of radiation reactions along with basic drugs.

OBJECTIVE: To study the effect of the use of hydrogel compositions for the prevention and treatment of radiation reactions during irradiation of patients with rectal cancer.

MATERIALS AND METHODS: The study included 257 patients, including 146 men and 111 women aged 27 to 88 years, the median was 59 years old, who lived in St. Petersburg, the Leningrad Region and in other regions of the Russian Federation, who received radiation therapy since 2013 to 2019 for rectal cancer. The severity of radiation reactions was assessed by the current RTOG/EORTC. Basic drug therapy, including non-steroidal anti-inflammatory drugs, antispasmodics, hemostatic agents, oil mixtures, etc., was used in 47% of patients. In the course of radiation therapy, 35 patients were prescribed hydrogel-based composite preparations with derinat, dioxidine and lidocaine.

Statistics: Data processing was carried out using the Excel spreadsheet editor, as well as the Statistica 10 for Windows statistical data processing software package.

RESULTS: Radiation proctitis was registered in 81 (31.5%), dermatitis in 50 (19.5%), cystitis in 45 (17.5%), enterocolitis, enteritis or colitis in 28 (10.9%), hematological toxicity in 8 (3.1%), vaginitis in 8 (3.1%), other in 7 (2.7%) patients. Taking into account that the bladder is the most frequently irradiated organ in cases where the target tumor is localized in adjacent organs of the small pelvis, as well as the lack of prevention and treatment standards (golden standard), radiation cystitis, which poisons the lives of apparently healthy patients, was carried out study of the effect of hydrogel compositions in the appointment of these drugs before, during and after the end of radiation therapy compared with the control. In the study group, a later onset of cystitis was noted (with SD from 20 to 34 Gy), the frequency of cystitis was 9% (p<0.05), the severity did not exceed 1 degree. In the control group, radiation reactions occurred when SD reached 14 to 27 Gy. RIC grade 1 was diagnosed in 10.3%, grade 2 in 8.8%, grade 3 in 5.9%. The overall frequency of RIC in the control group was 25%. Thus, the frequency of RIC in the control group significantly exceeded that in the main group. Further observations showed that patients, diagnosed with rectal cancer, who received hydrogel compositions suffered from overall incidence of late radiotherapy complications 2 times lower — 8.2% vs. 17.2%, respectively (p<0.05).

DISCUSSION: The impact of radiation reactions and complications on the quality of life of rectal cancer patients is actively discussed in the Russian Federation and abroad. At the same time, the incidence of rectal cancer in the world is growing, as well as the need for radiation therapy. Radiation cystitis is a recognized complication of radiation therapy of the pelvic organs. The frequency of RIC, according to various authors, ranges from 23 to 80%. Hydrogel compositions are one of the proven effective means of combating radiation damage.

CONCLUSION: the presence of radiation reactions during pre/postoperative radiation therapy for rectal cancer significantly contributes to a decrease in the five-year survival rate of patients. The frequency of radiation cystitis significantly decreases against the background of the appointment of hydrogel compositions before, during and after radiation therapy.

INTRODUCTION: Effect of adiuvant radiation therapy (RT) on oncologic outcomes is well-known and confirmed by different trials. Optimal time to start RT is 6–8 weeks after surgery. Increasing duration of RT delay beyond that interval leads to decrease in overall survival (OS) and makes loco-regional recurrence (LRC) more probable. However, more than 50% patients do not receive adjuvant treatment in time (Mitra S. et al., 2022). Overall treatment time (77–100 days) is another factor that influences effectiveness of adjuvant RT. In order to keep within that time limits non-conventional regimens of RT can be used.

OBJECTIVE: To test safety and feasibility of hypofractionated adjuvant RT in patients with locally advanced squamous cell carcinoma of oral cavity and oropharynx.

MATERIALS AND METHODS: Patients with stage III–IV squamous cell carcinoma of oral cavity and oropharynx (n=11) who underwent surgery and have to recieve adjuvant RT in 8 weeks and more after surgery are included. Dose was delivered using Volumetric Modulated Arc Therapy (VMAT) and simultaneous integrated boost.

RESULTS: Patients (n=11) completed RT successfully. Surgery-to-RT interval ranges between 9 and 15 weeks. Dose per fraction on high-risk-CTV varies between 2,5 and 2,75 Gy. Acute side-effects (oral mucositis grade II) presented after 27–32 Gy (11–13 fractions) in 9 patient out of 11 and reached maximum (oral mucositis grade III, radiation dermatitis grade II) at the end of the treatment.

CONCLUSIONS: Hypofractionated adjuvant RT (VMAT) can be safely used in patients with locally advanced squamous cell carcinoma of oral cavity and oropharynx and local acute toxicity can be controlled.