Advanced Materials Research Vol. 1084

Abstract: We study the possibility of using SPECT with ^99mTc-MIBI for the evaluation of the effectiveness of neoadjuvant chemotherapy for cancer of the larynx and laryngopharynx treatment. The study included 20 patients who have cancer of larynx or laryngopharynx. The patients underwent SPECT with ^99mTc-MIBI before treatment and after two courses of neoadjuvant chemotherapy. In processing the results indices tumor / submandibular salivary gland and tumor / parotid gland were calculated. These results indicate that in the group of patients with tumor regression of more than 30%, a decrease of the calculated parameters was also more than 30%. At the same time calculated indices showed a decrease of less than 30% in patients with tumor regression of less than 30% on a scale RESIST.

Abstract: The purpose was to study the utility of technetium 99m - pyrophosphate in the diagnoses of inflammatory changes of the heart in patients with persistent atrial fibrillation. The study included 30 patients (20 men and 10 women, mean age is 46 ± 9.92 years) with idiopathic persistent atrial fibrillation. To identify the foci of inflammatory changes in the myocardium the scintigraphy with ^99mTc-Pyrphotech and myocardial perfusion scintigraphy with ^99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) was performed before the operation. Later, both scintigrams were combined. During the surgical intervention, in all patients an endomyocardial sampling for histological and immunohistochemical study was performed. Pathological accumulation of ^99mTc-Pyrphotech in the myocardium was detected in 8 (26%) of examined patients. In 20% of cases the cause of "idiopathic" form of AF is latent lymphocytic or polymorphocellular myocarditis of viral etiology. Scintigraphy with ^99mTc-Pyrphotech can serve as one of the primary methods for non-invasive diagnosis of myocardial inflammation at the given form of arrhythmia.

Abstract: In this study we used technetium-99m-labeled lipophilic complex of methoxy-isobutyl-isonitrile (^99mTc-MIBI) and iopromide to assess coronary atherosclerosis in patients with coronary artery disease (CAD). The study included 33 patients with CAD who underwent myocardial perfusion scintigraphy with ^99mTc-MIBI and computed tomography angiography (MDCTA) with iopromide. Patients who have comparable with the population-wide level risk of coronary events are characterized by the presence of borderline and significant stenosis 83% and 86%, respectively. ^99mTc-MIBI and iopromide can be used to assess the severity of coronary atherosclerosis in patients with CAD.

Abstract: The objective of this study is to assess perfusion and metabolic state of the left ventricular in patients with dilated cardiomyopathy (DCM) using scintigraphy with MIBI and BMIPP, as well as to develop the predictors of efficacy of cardiac resynchronization therapy (CRT). The study included 51 patients with DCM who underwent CRT. Correlation between the values of LV ESV after CRT and preoperative perfusion and metabolic defects sizes was detected. "Responders" and "non-responders" groups were significantly different from the perfusion and metabolic defects sizes. Myocardial perfusion-metabolic scintigraphy can be used as additional criteria for the selection of patients for CRT.

Abstract: The objective of this study was to identify the signs of the right ventricular dysfunction in patients with non-massive pulmonary artery thromboembolism (PE) using radionuclide gated blood pool SPECT (GBPS). The study included 55 patients: 40 with PE, and 15 - control group. Radionuclide studies included perfusion-ventilation scintigraphy and GBPS. GBPS results suggest that the signs of right ventricular dysfunction in PE are: the reduction in its stroke volume, as well as reduction in the peak filling and ejection rate. GBPS results allow distinguishing acute thromboembolism and chronic post-thromboembolic pulmonary hypertension.

Abstract: The study of radionuclide determination of SLN and optimization of surgical treatment in organ-sparing treatment of invasive cervical cancer included 26 patients with cervical cancer of stage I. To identify sentinel lymph nodes a nanocolloid was administered one day prior to the planned operation. Sentinel lymph nodes were identified in 26 patients. A comparative evaluation of the sensitivity of techniques for determining SLN, depending on the method, has showed that the SPECT sensitivity was 72%, with radiometry this indicator was 93.3%. The technique of intraoperative radiometric determination of SLN is more efficient in comparison with SPECT. The optimum is the combined use of both techniques, when the probability of SLN detection increases to 91.4%.

Abstract: The study included 17 patients. All patients with cancer of larynx and hypopharynx were injected with nanocolloid labeled with 99mTc. In total 22 lymph nodes are identified. In the study of distant sentinel lymph nodes the presence of metastatic disease was revealed in 2 patients (11.8%). In 15 patients (88.2%) there was no metastatic lesion of SLN, and nodal disease progression was not recorded during further observation. Thus, in our study we did not observe the phenomenon of the so-called "jumping" metastases. Single-photon emission computed tomography and intraoperative radiometric display allow determining the “sentinel” lymph nodes after subserous administration of radioactive colloid with a sensitivity of 100% and a specificity of 100%.

Abstract: In this research we have studied contrast composition in the form of an aqueous solution containing gadolinium oxide (Gd₂O₃), diethylenetriaminepentaacetic acid (DTPA), medical polymer - polyvinylpyrrolidone mol. sq. (12000 ± 5000) daltons in an amount of 0.5-5 wt. %. To reduce the content of free gadolinium in the composition it has been suggested to change the stoichiometric ratio of the concentrations of DTPA/Gd₂O₃ in the mixture. The studies have shown that at a concentration ratio of DTPA/Gd₂O₃, 2.07 - 2.10 the impurity content of free gadolinium is at least 0.25%, which is significantly below the regulated value - 0.5%. The conducted biomedical tests have confirmed the functionality of the resulting contrast composition.

Abstract: The paper studies the melting parameters of the complexes of water soluble cationic 3N- and 4N-pyridyl porphyrins with different peripheral substituents (oxyethyl, buthyl, allyl, metallyl) with DNA. The results indicate that the presence of porphyrin changes the shape and parameters of DNA melting curve. The porphyrin concentration increase results in the increase of the melting temperature (Tm) and melting interval (ΔT) of DNA. With the porphyrin-DNA concentration ratio ν = 0.01, changes of melting temperature have not been observed. The melting intervals almost do not change upon the addition of the 4N- porphyrins, while the decrease of ΔT is observed in the presence of 3N-porphyrins. Because of the intercalation binding mechanism occurring in GC-rich regions of DNA, we assume that 3N-porphyrins intercalated in GC-rich regions, reduce the thermal stability of these sites, bringing them closer to the thermal stability of the AT-sites, which is the reason for the decrease in melting interval. While with the relative concentration ν = 0.01 for 4-N porphyrins the external binding mechanism “turns on” and destabilizing effect of porphyrins on GC-pairs compensated by their stabilizing effect on AT-pairs. As a result, no change in the melting parameters of DNA is observed upon complexation with these porphyrins.

Abstract: When a cancer type proves to be radioresistant to treatment with X-rays, the use of neutrons may constitute therapeutic gain provided the cells are relatively sensitive to high-LET radiation. In this work studies with different tumor cell types are reported following exposure to either photons or different neutron energies used in clinical radiation therapy. Potential for therapeutic gain is clearly noted for neutrons with a mean energy of 6 MeV whilst that for 29 MeV neutrons is dependent on the cell types used in the study.