Evaluation of the Radiation Dose of an Embryo/Fetus during Lymphoscintigraphy (Sentinel Lymph Node Mapping) in Pregnant Patients with Breast Cancer

Purpose: To develop a method for evaluation of the radiation dose of an embryo/fetus during lymphoscintigraphy (sentinel lymph node mapping) in pregnant patients with breast cancer.Material and methods: Two pregnant women (aged 43 and 30) with breast cancer stage IIA (T2N0M0), during the second trimester of pregnancy. We used a lymphotropic colloidal radiopharmaceutical labeled with 99mTc. To evaluate the radiation dose of an embryo, each patient had 6 individual dosimeters, which were placed around the abdomen using an elastic bandage at equal distances around the abdomen. Additionally, we placed the 7th dosimeter, it was placed near the injection site (under the mammary gland). After installing individual dosimeters, radiocolloid was injected into the affected mammary gland at four points (periareolar). The administered activity of radiopharmaceutical was 32.5 MBq, and 51.5 MBq. Lymphoscintigraphy was performed 1 hour after injection. First patient underwent sector resection of the left breast with SLN biopsy. The second patient underwent right mastectomy with SLN biopsy and breast reconstruction surgery using a tissue expander.Results: Based on the results of the study, the dose rate was calculated, on the basis of which the fetal radiation doses were calculated in both patients. Comparison of the mathematical data of both patients shows that, the calculated and experimental values of radiation exposure to the fetus during the radionuclide study of sentinel lymph nodes practically coincide. The obtained data shows that during pregnancy (280 days) the embryo/fetus will accumulate a natural radiation background dose of 1960 μSv, which is 2 times higher than the dose from the radionuclide study of sentinel lymph nodes. Thus these results verify the safety of SLN biopsy technology in pregnancy.Conclusion: 1. Radionuclide diagnostic studies of pregnant women determine radiation doses to the embryo/fetus that do not cause any radiation-induced effects in the prenatal period, and the probability of the occurrence of stochastic radiation-induced effects is several times lower than the incidence of endogenous cancers. 2. Radionuclide examination of sentinel lymph nodes appears to be safe for the fetus when conducted in pregnant women diagnosed with breast cancer. 3. In Russian Federation this method is used for the first time in pregnant women with diagnosed breast cancer. This technology has not been previously described in Russian literature.

The Role of PET/CT with 68Ga‑PSMA in the Primary Diagnosis of Prostate Cancer

Relevance: Prostate cancer is one of the most frequently diagnosed malignant neoplasms of the genitourinary system in men in the world. Recently, there has been an active introduction into clinical practice of positron emission tomography technology combined with computed tomography (PET/CT) with 68Ga‑PSMA‑617 based on prostate‑specific membrane antigen (PSMA), the capabilities of which significantly increase the effectiveness of the diagnosis of prostate cancer at various clinical stages compared with routine methods used in the staging of prostate cancer.Purpose: To compare the diagnostic effectiveness of PET/CT with 68Ga‑PSMA‑617 with traditional methods of radiation imaging (computed tomography, magnetic resonance imaging and bone scan) in the staging of prostate cancer and to clarify the impact of this technology on the choice of surgical treatment.Material and methods: PET/CT with 68Ga‑PSMA was performed in our center in order to stage the verified prostate cancer in 109 patients aged 48 to 80 years (median 64.5). The selection criteria were: a PSA level of more than 5 ng/ml, the presence of a newly identified, histologically verified prostate cancer, lack of treatment, suspicion of metastatic lesion of the lymph nodes of the pelvis and skeleton. Patients were divided into groups by prostate‑specific antigen level, Gleason score, and d’Amico.Results: In the analysis of PET/CT results and MRI/CT comparison and Bone scan, 56 (51.4 %) of 109 patients showed a change in the TNM stage. A change in the data on the local spread of the tumor with an increase in the stage according to criterion T due to the detection of pathological accumulation of RFP in seminal vesicles was detected in 21 (37.5 %) of 56 patients. Additionally, according to PET/CT data, 13 (23.2 %) of 56 patients were found to have lesions of regional lymph nodes (N). Metastatic lesions of distant lymph nodes (M1a) and bones (M1b), not visualized during routine radiation examination, were observed in 32 (57.1 %) and 36 (64.3 %) of 56 patients, respectively.Conclusions: The use of PET/CT 68Ga‑PSMA‑617 in patients with newly diagnosed prostate cancer at the staging stage allows us to obtain valuable additional information about the local, regional and long‑term prevalence of the pathological process, and in some cases — to change the stage of the disease by TNM (usually by increasing it), which has a significant impact on the tactics of therapeutic measures and the choice of the optimal method of therapy for prostate cancer.

Shear Wave Ultrasonic Elastometry in Diagnostics of Metastatic Lymph Nodes in Neck Thyroid Cancer

Purpose: Determination of informative value of a new method of ultrasound tomography, based on the properties of elasticity of soft tissues, in the differential diagnosis of metastatic lesions of the lymph nodes of the neck thyroid cancer.Material and methods: To assess the capabilities of shear wave ultrasound elastometry in the diagnosis of metastatic lesions of the lymph nodes in thyroid cancer, a study was carried out with 45 patients with suspected thyroid cancer. The work was performed by devices Acuson S2000 Siemens, Avius hi vision Hitachi using a linear sensor with a frequency of 5–12 MHz. For each object of the study, from 5 to 10 measurements of the shear wave velocity in m / s were made, depending on the size of the lymph nodes.Results: Reliable results were obtained in the group of altered lymph nodes (statistical significance p < 0.05). Interquartile intervals and the most common values of shear wave velocities do not overlap: in metastases — 2.20– 3.36 m/s, with hyperplasia of lymph nodes — 0.70–1.88 m/s, and medians show a significant difference in velocities: metastases — 3.00 m/s, hyperplastic lymph nodes 1.38 m/s.Conclusions: Shear wave elastography objectifies ultrasound studies, obtaining specific indicators of shear wave velocity in the areas of interest, and can be used as an additional diagnostic tool in the differential diagnosis of metastatic and hyperplastic lymph nodes.

Metabolic Tumor Volume for Patients with Lymphomas

Visual analysis of positron emission tomography/computed tomography (PET/CT) scans and semiquantitative parameter of glucose’s standardized uptake value are used in PET/CT with 18F-fluorodeoxyglucose (18F-FDG). Recently some volumetric parameters, which can evaluate metabolic tumor volume for patients with lymphomas and total lesion glycolysis in the tumor sites are established. In our study this problem was analyzed for different types of lymphomas considering clinical importance of these rates and their bond to known factors of international prognostic index.

Role of Radiology Methods in Differential Diagnosis of Fibrous Dysplasia of Base of the Skull

Purpose: Improvement of the differential diagnosis of fibrous dysplasia of the of the base of the skull on the basis of X-ray computed tomography data, taking into account clinical and medical data.Material and methods: The results of examination of 24 patients with lesions of the base of the skull were analyzed. Group 1: 15 patients with fibrous dysplasia, directed to examination with a diagnosis of osteoplastic metastases of the base of the skull. Group 2: 9 patients with metastases to the base of the skull. All patients underwent computer tomography and SPECT/CT.Results: Comparison of clinical and radiological symptoms in patients with metastatic lesions of the base of the skull (group 2) and patients with fibrous dysplasia of the base of the skull (group 1) allows us to state that errors in the differential diagnosis of bone metastases and fibrous dysplasia of the base of the skull in a number of cases are associated with a lack of awareness of radiologists.Conclusion: The presented data will help to improve the diagnosis of fibrous dysplasia of the base of the skull.

Clinical Case of Visceral Toxocariasis in a Patient with Breast Cancer in Anamnesis

We report a case of visceral toxocariasis of the liver in a patient after complex treatment of breast cancer. It was decided to demonstrate this clinical case in a view of the complexity of the differential diagnosis of visceral toxocariasis and metastatic liver disease.

Methodological Aspects of Measuring Metabolic Tumor Volume in Patients with Diffuse B-Cell Large Cell Lymphoma by PET/CT with 18F-FDG

Introduction: Metabolic Tumor Volume (MTV) and Total Tumor Lesion Glycolysis (TLG) are used in 18F-fluorodeoxyglucose Positron-Emission Tomography combined with Computed Tomography (18F-FDG PET/CT) as functional markers, indicating tracer uptake in whole tumor. MTV and TLG are not yet engaged in clinical practice, because volume measurement accuracy depends on the selected measurement method, and optimal MTV and TLG segmentation is not established.Purpose: Assessment of accuracy of metabolic tumor volume measurement ways, using 18F-FDG PET/CT in patients with Diffuse Large B-Cell Lymphoma (DLBCL).Material and methods: Baseline 18F-FDG PET/CT performed in 21 patients with DLBCL. Tumor Volume (TV), measured on contrast enhanced CT (CTTV), considered as reference. While measuring MTV, we aimed to achieve a 1:1 ratio between CTTV and MTV. If anatomical and metabolic tumor contours matched, MTV was considered true (MTVtrue). Overall MTV and TLG measurements are 254. Tumor contouring, using relative thresholds, was made around Standardized Uptake Value (SUVmax) of tracer in tumor and intact liver.Results: On CT, the size of the lesions varied from 24 to 241 mm, M = 103.4±62.3, Me = 93 (48.5–155.5). In 15 (71.4 %) foci, hypodense areas of necrosis were determined. PET imaging revealed high tracer uptake in all foci of varying degrees of intensity. SUVmax values in tumors ranged from 5.8 to 30.5, Me = 20.4 (17.3–23.2). No significant correlation was found between the size of the foci and SUVmax (ρ = 0.17, p = 0.4744). The best accuracy in measuring MTV was observed when several thresholds were applied: VOIPERCIST, VOI2.5, VOIauto-contour, as well as VOI10 %, VOI15 % and VOI20 %. The optimal absolute threshold values were SUV values in the range from 2 to 3, and relative values in the range from 10 % to 20 % of the SUVmax in the tumor. MTV underestimation was more often determined using relative cut-off indices in the range of25–50 % and SUV thresholds ≥ 5.3.Conclusion: The results obtained showed that the use of a single threshold value for MTV segmentation in patients with DLBCL is not advisable. The choice of the MTV measurement method should be carried out individually for each lesion, taking into account its shape, size and structure, as well as the intensity and uniformity of tracer uptake in the tumor and adjacent anatomical structures.

Percutaneous Angiographically Assisted Cryoablation of Renal Cell Carcinoma under the Control of Flat-Detector Computed Tomography: Capabilities and Potential Advantages of the Technique

Purpose: Percutaneous cryoablation (PCA) of renal cell carcinoma (RCC) stage T1a (≤4 cm) generally performed using MDCT with intravenous contrast material administration. Most interventional radiology departments are not equipped MDCT scanners and this is holding back widespread adoption of this technique into practical medicine. Flat-detector computed tomography (FDCT) is included in the standard equipment of modern angiographic systems, which makes it possible to combine the technologies of computed tomography with various technologies of intra-arterial contrasting and endovascular treatment. The purpose of the study was to assess the possibilities and potential advantages of using intraarterial contrasting during FDCT-controlled PCA of RCC T1a.Material and methods: Since 2017 angiographically assisted PCA under the FDCT control performed in 14 patients with RCC T1a. The procedure was performed in the X-ray operating room on an Artis Zee Floor angiographic unit with FDCT function and iGuide Needle Guidance and 3D/3D Fusion technologies (Siemens, Germany) using the SeedNet Gold system and IceEDGE 13 G, IceRod 17 G or IceSphere 17 G cryoprobes (Galil Medical, USA). At all stages of the procedure, FDCT-arteriography of the kidney (FDCT-A) performed according to the original technique: injection into the renal artery 12 ml of non-ionic contrast materials at a rate of 1 ml/s and performing scanning 5 s after the start of contrast materials injection.Results: The primary technical efficiency of FDCT-controlled PCA of RCC T1a was 92.9 %, the secondary — 100 %. Complications of grade 3 according to the CIRSE classification were identified in three patients (21.4 %), complications of grade 4, 5 and 6 not observed. The use of arterial access and the FDCT-A execution at different stages of PCA had the following advantages: 1) high-quality visualization of the tumor with minimal consumption of contrast materials; 2) simple and accurate positioning of cryoprobes using the iGuide Needle Guidance program; 3) estimation of the future ablative margin by fusion FDCT data about tumor with FDCT data about ice ball; 4) reliable diagnosis of bleeding after removal of cryoprobes with the possibility of immediate performing of endovascular hemostasis.Conclusion: Percutaneous angiographically assisted cryoablation under the FDCT control is an affordable, safe and effective technology for the treatment of RCC T1a, which has a number of potential advantages compared to performing procedures using MDCT control. Further research is advisable to study of this PCA technique with its subsequent possible introduction into the routine practice in Interventional Radiology departments of multidisciplinary oncological hospitals.

Radioiodine Ablation for Thyroid Cancer. Historical and Modern Aspects. Literature Review

Thyroid cancer is the most common oncological pathology of the endocrine system organs with a continuing trend towards an increase in the incidence. Radioiodine therapy (RIT) is the second stage of combined treatment, it is carried out only as an adjuvant treatment, it is an uncontested method of radio-targeted therapy for distant metastases of differentiated thyroid cancer (DTC). The method of radioiodine therapy is based on the unique natural affinity of iodine atoms for the follicular epithelium of the thyroid gland and DTC cells. Determination of indications for RIT is based on stratification of recurrence risk, persistence, and disease prevalence. Over the past 15 years, the world’s leading professional communities have repeatedly revised approaches to risk stratification. Consideration of the mutational profile of the tumor and the theranostic approach have become significant innovations.Radioiodine therapy can be presented in the form of three modes: ablation of residual thyroid tissue, treatment of residual tumor and treatment of distant metastases. These regimens differ in the administered therapeutic activity of 131I, which looks logical from the point of view of the necessary personalization of the treatment. At the same time, in scientific circles, disputes about the absence of significant differences in the used therapeutic activities of 131I prescribed for radioiodine ablation outside the personalized approach do not subside.

Possibilities of PET/CT with 18F-PSMA-1007 in the Diagnosis of Triple Negative Breast Cancer: a Case Study

Breast cancer (BC) is one of the most common cancers and the leading cause of cancer death in women. Triple negative breast cancer (TNBC) is a specific subtype of breast cancer that does not express estrogen receptors (ER), progesterone receptors (RP) or human epidermal growth factor receptor-2 (HER-2), has certain clinical features, a tendency to relapses and poor prognosis. Various studies demonstrate that prostate-specific antigen (PSA) is not strictly specific for prostate cancer, and can be produced by other tumor pathologies. In routine practice, PET/CT for TNBC is performed with 18F-FDG. However PET/CT with 18F-PSMA-1007 can be used as the method of choice with high theranostic potential. Here is a clinical case of a patient with TNBC who underwent PET/CT with 18F-FDG and 18F-PSMA-1007.