Bioinformatics approach for prediction and analysis of the Non-Structural Protein 4B (NSP4B) of the Zika virus.

BACKGROUND: The Nonstructural Protein (NSP) 4B of Zika virus of 251 amino acids from (ZIKV/Human/POLG_ZIKVF) with accession number (A0A024B7W1), Induces the production of Endoplasmic Reticulum ER-derived membrane vesicles, which are the sites of viral replication. To understand the physical basis of how proteins fold in nature and to solve the challenge of protein structure prediction, Ab-initio and comparative modeling are crucial tools. RESULTS: The systematic in silico technique, ThreaDom, had only predicted one domain (4 - 190) of NSP4B. I-TASSER, and Alphafold were ranked as the best servers for full-length 3-D protein structure predictions of NSP4B, where the predicted models were evaluated quantitatively using benchmarked metrics including C-score (-3.43), TM-score (0.77949), RMSD (2.73), and Z-score (1.561). The functional and protein binding motifs were realized using motif databases, secondary and surface accessibility predictions combined with Post-Translational Modification Sites (PTMs) prediction. Two highly conserved protein-binding motifs (Flavi NS4B and Bacillus papRprotein), together with three (PTMs) (Casein Kinase II, Myristyl site, and ASN-Glycosylation site) were predicted utilizing the Motif scan and Scanprosite servers. These patterns and PTMs were associated with NSP4B's role in triggering the development of the viral replication complex and its participation in the localization of NS3 and NS5 on the membrane. Only one hit from Structural Classification of Protein (SCOP) matched the protein sequence at positions 10 to 397 and was categorized six-hairpin glycosidases superfamily according to CATH (Class, Architecture, Topology, and Homology). Integrating this NSP4B information with the templates' SCOP and CATH annotations achieves it easier to attribute structure-function/evolution links to both previously known and recently discovered protein structures.

Comparing biological and physical cost functions in VMAT planning for pediatric nasopharyngeal cancer.

BACKGROUND: Volumetric Modulated Arc Therapy (VMAT) is an option for the delivery of Radiotherapy treatment technique for pediatric nasopharyngeal cancer, VMAT is the most common treatment technique for pediatric nasopharyngeal cancer. The use of a combination of both biological and physical parameters in VMAT planning optimization may produce better target coverage and sparing of critical organs. This work was to compare Biological Cost Functions (BCFs) and Physical Cost Functions (PCFs) in the VMAT of pediatric nasopharyngeal cancer patients. METHOD: VMAT plans for 20 nasopharyngeal pediatric cancer patients were created using Monaco 5.11® treatment planning system (TPS). Three VMAT plans were retrospectively generated for each patient using BCFs, PCFs and mixed plan with a total dose of 61.2 Gy in 34 fractions to planning target volume (PTV). All plans were adjusted to deliver 95% of the prescribed dose to 95% of the PTV. The calculated plans were qualitatively and quantitatively evaluated using the dose-volume histogram (DVH). RESULTS: The coverage of the target and the maximum dose for the three plans were nearly the same, and better sparing was achieved in the serial organs (spinal cord and brain stem) with PCFs. On the contrary, more dose spring was observed using the BCFs in the organs at risk (OARs) that were not involved in the dose optimization, such as the optic nerve maximum dose, with a significant p-value (0.035 and 0.0001) respectively. Using the PCFs, both parotids received a lower mean dose, but not for the oral cavity, which had a lower mean dose using BCFs (p=<0.0001). The same values of tumor control probability (TCP) were found for both cost functions in PTVs and normal tissue complications probability (NTCP) (99%). The values reported were as follows: spinal cord = 0.5%, brain stem = 19.1%, and brain = 90.7% for BCFs, compared to spinal cord = 0.3%, brain stem = 14.9%, and brain = 90.7% for PCFs. The delivery time was found to be less in BCFs (p=0.005). CONCLUSION: The BCFs are superior to the PCFs in conformity index and time of radiation delivery. However, PCFs were better at dose sparing for the serial organs and achieving a sharper falloff dose around the involved volumes. A patient-specific clinical compromise is recommended to gain the best plan that meets the clinical goals.

Trophic state and potential productivity assessment for Qaroun Lake using spatial techniques.

Qaroun Lake is one of the most important Egyptian lakes which, recently, have been exposed to severe degradation in water quality and fish productivity. In this manuscript, Carlson's trophic state index (CTSI) was used to evaluate the trophic state, while the trophometric index (TMI) was used to assess the potential productivity of Qaroun Lake. The present study is one of the initial attempts to investigate these indices in Qaroun Lake. To achieve this work, an integrated multidisciplinary approach was adopted integrating field investigation, geographic information system, and data analysis. CTSI combines three variables of water quality: chlorophyll-a (CHL-a), total phosphorus (TP), and transparency measured by Secchi disk depth (SDD). The result of overall CTSI showed the hypereutrophic state is represented by 62% and eutrophic state is represented by 38% of the total lake's area. Moreover, the calculated TMI indicated the average potential productivity value (PP) is 619 t. It can be concluded that the hypereutrophic is the dominant state in Qaroun Lake. The present study recommends the application of TMI model to evaluate and monitor the changes in Qaroun Lake's potential productivity in response to the changing environmental conditions and other biological pressures (e.g., Isopoda paraside).

Efficient pulmonary nodules classification using radiomics and different artificial intelligence strategies.

OBJECTIVES: This study aimed to explore and develop artificial intelligence approaches for efficient classification of pulmonary nodules based on CT scans. MATERIALS AND METHODS: A number of 1007 nodules were obtained from 551 patients of LIDC-IDRI dataset. All nodules were cropped into 64 × 64 PNG images , and preprocessing was carried out to clean the image from surrounding non-nodular structure. In machine learning method, texture Haralick and local binary pattern features were extracted. Four features were selected using principal component analysis (PCA) algorithm before running classifiers. In deep learning, a simple CNN model was constructed and transfer learning was applied using VGG-16 and VGG-19, DenseNet-121 and DenseNet-169 and ResNet as pre-trained models with fine tuning. RESULTS: In statistical machine learning method, the optimal AUROC was 0.885 ± 0.024 with random forest classifier and the best accuracy was 0.819 ± 0.016 with support vector machine. In deep learning, the best accuracy reached 90.39% with DenseNet-121 model and the best AUROC was 96.0%, 95.39% and 95.69% with simple CNN, VGG-16 and VGG-19, respectively. The best sensitivity reached 90.32% using DenseNet-169 and the best specificity attained was 93.65% when applying the DenseNet-121 and ResNet-152V2. CONCLUSION: Deep learning methods with transfer learning showed several benefits over statistical learning in terms of nodule prediction performance and saving efforts and time in training large datasets. SVM and DenseNet-121 showed the best performance when compared with their counterparts. There is still more room for improvement, especially when more data can be trained and lesion volume is represented in 3D. CLINICAL RELEVANCE STATEMENT: Machine learning methods offer unique opportunities and open new venues in clinical diagnosis of lung cancer. The deep learning approach has been more accurate than statistical learning methods. SVM and DenseNet-121 showed superior performance in pulmonary nodule classification.

Taxonomic and functional structure of macrobenthic invertebrate communities and their response to environmental variables along the subbranches of the Nile River (rayahs), Egypt.

Macrobenthic invertebrate communities serve as markers of anthropogenic stress in freshwater ecosystems. In this study, 17 sampling sites were selected from two Nile river subbranches (El-Rayah El-Behery and El-Rayah El-Nassery) and subjected to different anthropogenic influences to explore the ecological environment and characteristics of macrobenthos communities. Macrobenthos were studied using taxonomic diversity and biological trait analysis to investigate how human activity and variation in water quality affect their structure and function. A total of 37 taxa represented by 43,389 individuals were recognized. The communities are composed chiefly of Oligochaeta and aquatic insects. Multivariate statistical analyses found that the most influential environmental variables in the structural and functional community were sodium, dissolved oxygen, silicate, pH, calcium, and cadmium. At high levels of pollution, notably sewage and industrial pollution in the northern part of El-Rayah El-Behery, characteristics such as larger body size, detritus feeders, burrowers, and high tolerance to pollution predominated, whereas at low levels of pollution, features such as small body sizes, scraper and predator feeders, intolerant and fairly tolerant of pollution, and climber and swimmer mobility are predominant. The results confirm our prediction that the distribution of macroinvertebrate traits varies spatially in response to environmental changes. The diversity-based method distinguished impacted sewage and industrial sites from thermal effluent sites, while the trait-based approach illustrated an apparent variance between the ecological status of contaminated regions. Therefore, the biological features should be employed in addition to structural aspects for assessing the biodiversity of macroinvertebrate communities under environmental stressors.

Variations induced by body weight and background lesion normalization in standardized uptake value estimated by F18-FDG PET/CT.

AIM: This work aims to study the impact of different SUV variants in terms of mean and maximum measures as well as various normalization methods with respect to body weight, body mass index, body surface area, and lean body mass in patients with lymphoma. METHODS: Sixty-nine patients (34 male-35 female) were retrospectively selected. All patients had undergone F18-FDG PET/CT using the standard imaging protocol. In the first part of this study, SUVmean and SUVmax of patients' lesions and three background sites including liver, aorta, and muscle were determined. Then, the normalization of lesion SUV to body weight and body background sites was performed. The ratio of lesion SUVmax to body background sites (muscle, aorta, and liver) SUVmax was determined in addition to the ratio of lesion SUVmean to body background sites SUVmean. The second part of the study included the calculations of the body mass index (BMI), body surface area (BSA), and lean body mass (LBM). The normalization of lesion, liver, aorta, and muscle SUV to BMI, BSA, and LBM was calculated and compared to each other. RESULTS: After performing the appropriate statistical calculations, the results showed that there is a significant difference in SUV measurements between the three background sites. Lesions normalized to the liver were significantly lower than those normalized to aorta and muscle and the results also showed a higher magnitude of lesions normalized to muscle in comparison to the aorta. The SUVmax and SUVmean normalized to different body weight indices showed the lowest variation with BSA and BMI while being increasingly higher with lean body mass using the two methods James and Janmahasatian, respectively, and then highest with body weight. CONCLUSION: The SUVmax and SUVmean showed lower variance in comparison to other background regions. Less variation was also remarkable in SUVmean normalized to BSA and Janma lean mass and also when SUVmax is normalized to James lean body mass. The SUVmax normalized to lean (i.e., James) as well as SUVmean normalized to lean (i.e., Janma) and BSA showed a significant independence with body weight.

Environmental risk assessment associated with acidic volcanics in Egypt.

The present work aims to study gamma rays emitted by radionuclides such as 238U, 232Th and 40K from acidic Monqul volcanics. The studied volcanics are represented by a thick stratified lava flows interbanded with their pyroclastics. They are composed of thick lava flows of andesite and, to a lesser extent of basalt, and acidic volcanics including rhyolite and dacite. The average values of 238U, 232Th and 40K are (46 ± 24 Bq kg-1), (62 ± 11 Bq kg-1) and (1227 ± 318 Bq kg-1) in the rhyolite-dacite samples are greater than the worldwide average. The variation of radioactive bearing minerals observed inside granite faults produced the great amounts of radioactivity perceived in the samples. Calculating radiological risks is used to assess the public's radioactive risk from radionuclides revealed in the studied Rhyolite-dacite samples. The acceptable limit for excess lifetime cancer (ELCR) evaluations has been exceeded. As a result, Rhyolite-dacite are inappropriate for apply in building materials.

Differential effects of cancer modifying agents during radiation therapy on Ehrlich solid tumor-bearing mice: A comparative investigation of metformin and ascorbic acid.

BACKGROUND: This work was carried out to compare the modifying roles of ascorbic and metformin during Ehrlich (ESC) tumor-bearing mice irradiation. METHODS: Fifty Swiss albino male mice were segmented into seven groups, including one control group and six Ehrlich induced tumors treated with ascorbic, ascorbic plus radiation, metformin, metformin plus radiation, and radiation only. Many tests, including behavioral, biochemical, immunohistochemistry, gene expression, DNA fragmentation, oxidative stress markers, and EPR, were performed to interrogate the modifying effects on tumor and liver tissues. RESULTS: Remarkable apoptosis was found in metformin irradiated animals compared to irradiated ascorbic counterparts. The irradiated metformin mice showed the greatest reduction in PCNA. There was a significant reduction of DNA fragmentation in the liver tissues of the irradiated metformin group. Irradiated metformin and irradiated ascorbic acid animals showed a reduced signal of ERK as well as c-Fos genes. There was a tendency of metformin and metformin irradiated animals to reduce MDA levels in liver tissues. ESC-bearing mice treated with ascorbic or metformin showed an improvement in the spontaneous alternation percentage (SAP%) and improved short-term memory. There was also an improvement in long memory tests. CONCLUSIONS: The study added more preclinical evidence on the utility of metformin in cancer treatment during radiotherapy. Metformin was shown to reduce lipid peroxidation in irradiated healthy tissues, increase tumor cytotoxicity, downregulate critical pathways involved in tumor progression and proliferation, and enhance tumor apoptosis. Controlled clinical trials using metformin are highly warranted.

Excess Lifetime Cancer Risk Associated with Granite Bearing Radioactive Minerals and Valuable Metals, Monqul Area, North Eastern Desert, Egypt.

The present work is concerned with assessing the cancer risk contributed by the studied granite types including valuable metals, such as Cu, Au, and Ba mineralization, as well as radioactive-bearing mineralization, such as monazite and zircon, in south Monqul at Wadi Makhrag El Ebel, north Eastern Desert, Egypt. The mineralization analyses illustrated that copper mineralization containing chrysocolla and tenorite minerals were restricted to the alteration zone, especially (argillic, phyllic, and propylitic) in monzogranite. However, barite veinlets had an ENE-WSW trend, while gold mineralization was confined to quartz veins having NE-SW trends. Monazite and zircon are radioactive-bearing minerals recorded in monzogranite causing high radioactive zones in south Monqul. The radionuclide activity concentrations were detected in the studied monzogranites. The mean values of AU (103 ± 91 Bq kg-1), ATh (78 ± 19 Bq kg-1), and AK (1484 ± 334 Bq kg-1) in the monzogranite samples were higher than the recommended worldwide average. The change in radioactive-transporting minerals found inside granite faults caused the high amounts of radioactivity seen in the samples. Due to the monzogranites being applied in building materials, the radiological hazards were assessed by calculating risk indices such as annual effective dose (AED) and excess lifetime cancer risk (ELCR). The acceptable limit for the ELCR readings was surpassed. As a result, the investigated monzogranite samples are not suitable for use in infrastructure materials.

Evaluation of Conformity and Homogeneity Indices Consistency Throughout the Course of Head and Neck Cancer Treatment With and Without Using Adaptive Volumetric Modulated Arc Radiation Therapy.

Purpose: Conformity indices (CI) and homogeneity indices (HI) are important tools for evaluating treatment plan quality. In this study, we evaluate the consistency of these indices with respect to anatomic changes undergone by patients. Methods and Materials: Fifty-five patients with advanced head and neck cancer were treated with simultaneous integrated boost volumetric modulated arc therapy. The initial plan (iplan) then was projected on the new computed tomographs (CT) and 2 adaptive plans (Aplans) for each patient were performed on the new CTs. A comparison of CI and HI between the iplan, hybrid plan (Hplan), and Aplan was performed. Results: There was a significant weight loss (P < .001) between CT1, CT2, and CT3, where the median weight at CT1 was 75.78 (68.95-83.42) kg, and 74.88 (68.35-82.2) kg at CT2 and 73.1 (67.6-80.7) kg at CT3. Also, gross tumor volume (GTV) showed significant decrease at CT1, CT2, and CT3. The initial GTV was 32.3 (21-58.6) cc and 28.24 (15.85-48.63) cc at CT2 and 25.12 (14.1-42.2) at CT3. In addition, there was a significant decrease in left parotid volume after 10 and 20 fractions; the median left parotid gland volume at CT1 was 31.04 (26.34-36.27) cc, then was 25.84 (19.19-28.59) cc after 10 fractions and 19.5 (13.53-22.25) cc after 20 fractions; the median right parotid volume at CT1 was 29.81 (24.6-38.75) cc and 22.38 (18.19-30.12) cc at CT2, then the volume fell to 17.74 (13.41-22.66) cc at CT3. Also, a significant increase in dose to organs at risk were noticed at Hplans, the median dose for brain stem at iplan was 5156 (4561-5324) cGy then increased to 5321 (4688-5545) cGy at Hplan1 then increased again to reach 5401 (4821-5812) cGy at Hplan2. The CI showed regression at Hplan1 and Hplan2 and then improvement at Aplan1 and Aplan2. The HI also showed regression in its value at the Hplans and then improved at the Aplans. Conclusions: Based on the results, we conclude that anatomic changes such as weight loss greatly affect the quality of plan, and with Aplans, we maintained the quality of plan by sustaining the values of CI and HI as in the iplan.

Assessment of Radiation Exposure Dose for Nuclear Medicine Workers from 18F-FDG, 99mTc MDP, and 99mTc.

BACKGROUND: Nuclear medicine or diagnostic radiology personnel are always exposed to low-level radiation from radionuclides used in medical diagnostics, which lead to potential biological hazards or effects. OBJECTIVE: External exposure for workers in two nuclear medicine centers was measured by recruiting 120 patients. METHODS: Three nuclear medicine examinations were performed using F18-FDG PET/CT,99mTc- MDP bones scan, and 99mTc thyroid scan by a digital radiation dosimeter. RESULTS: The average received accumulative radiation dose for workers was found to be 0.838±0.17, 0.527±0.11, and 0.270±0.05 µSv for F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. The annual effective dose for workers was estimated to be 2.09±0.42, 1.34±0.27, and 0.68±0.14 mSv, respectively. Moreover, the average patient-to-staff dose coefficients were found to be 0.024±0.005, 0.003±0.001, and 0.007±0.002 µSv m2/MBq h for F18- FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. CONCLUSION: It is clear from the results that the radiation doses received by workers during the nuclear medicine imaging examinations were less than the doses recommended by the International Commission on Radiological Protection (ICRP) for such examinations.

Radiation and chemotherapy variable response induced by tumor cell hypoxia: impact of radiation dose, anticancer drug, and type of cancer.

Hypoxia is a condition in which proliferating tumor cells are deprived of oxygen due to limited blood supply from abnormal tumor microvasculature. This study aimed to investigate the molecular changes that occur in tumor cell hypoxia with special emphasis placed on the efficacy of chemotherapeutic and radiation-related effects. Four commercially available chemotherapeutic agents: cisplatin, cyclophosphamide, doxorubicin, and 5-fluorouracil, were tested for their cytotoxic activity on the cancer cell lines PC3 (prostate), HepG2 (liver), and MCF-7 (breast). Tumor cell lines under hypoxia were treated with both IC50 concentrations of the different chemotherapeutic agents and irradiated with 5 and 10 Gy using a 137Cs gamma source. Hypoxia-inducible factor-1α (HIF-1α) protein levels were examined using an ELISA assay. Hypoxic cells showed a significant change in cell viability to all chemotherapeutic agents in comparison to normoxic controls. HepG2 cells were more resistant to the cytotoxic drug doxorubicin compared to other cancer cell lines. The flow cytometric analysis showed that hypoxic cells have lower levels of total apoptotic cell populations (early and late apoptosis) compared to normoxic cells suggesting decreased hypoxia-induced apoptosis in cancer cells. The highest reduction in HIF-1α level was observed in the MCF-7 cell line (95.5%) in response to the doxorubicin treatment combined with 10 Gy irradiation of cells. Chemoradiotherapy could result in minimal as well as a high reduction of HIF-1α based on cell type, type of chemotherapy, and amount of ionizing radiation. This study highlights future research work to optimize a combined chemoradiotherapeutic regime in individual cancer cell hypoxia.

Erector Spinae Block with Opioid Free Anesthesia in Cirrhotic Patients Undergoing Hepatic Resection: A Randomized Controlled Trial.

BACKGROUND: Hepatic resection is a major abdominal surgery with challenging pain management. We aimed to investigate the effect of erector spinae plane block (ESPB) with opioid free anesthesia (OFA) in cirrhotic patients scheduled for liver resection on perioperative pain management in terms of hemodynamic stability. Secondarily, we assessed time to first request for analgesia and perioperative fentanyl consumption, nausea and vomiting within 24 hours after surgery. METHODS: Forty patients were randomized to block group (n = 20): OFA with ESPB and conventional group (n = 20): conventional balanced anesthesia with opioids (OFA associated non-opioid drugs [dexmedetomidine, magnesium sulfate, xylocaine, and acetaminophen] and ESPB). Bilateral ESP block was done with ultrasound guidance at the level of thoracic vertebrae T 6-7, the local anesthetic dose was 20 mL Bupivacaine 0.25% with adjuvant dexmedetomidine (0.5 µg/kg) on each side. We monitored hemodynamic stability as the primary endpoint (heart rate, mean arterial blood pressure, and cardiac output). RESULTS: Bilateral ESPB offered somatic and visceral analgesia for hepatic resection patients with no intraoperative fentanyl required. Postoperatively, the block group with dexmedetomidine adjuvant to the local anesthesia drugs showed delay in the first request for analgesia (p = 0.092) and decreased fentanyl requirement (p < 0.001), so no patient in the ESP group suffered from postoperative nausea and vomiting compared to 50% in the conventional group (p < 0.001). CONCLUSION: Bilateral ESP block with OFA is an effective approach for intra- and postoperative analgesia in cirrhotic patients undergoing liver resection.

Quantifying inter- and intra-fraction variations of breast cancer radiotherapy with skin dose measurements.

Aim. The aim of the current study was to compare between the deep inspiration breath-hold (DIBH) technique and free-breathing (FB) method in the treatment delivery uncertainty of breast cancer radiotherapy using skin dose measurements.Methods. In a prospective manner, eighty patients were randomly selected for skin dose measurements, and they were assigned to two groups. DIBH (40 patients) and FB (40 patients). The systematic inter-fraction dose variation was quantified using the mean percentage error (MPE) between the average measured total dose per session in three consecutive sessions and the corresponding calculated point dose from the treatment planning system. The random inter-fraction dose variation was quantified using the standard deviation (SD) of the dose delivered by the medial or lateral tangential fields, or the total session dose in the three sessions (SDMT, SDLT, or SDtotal, respectively). While the random intra-fraction dose variation was quantified using the SD of the dose difference between the medial and lateral tangential fields in three consecutive sessions (SDMT-LT).Results. There was no statistically significant difference in MPE between the DIBH and FB groups (p = 0.583). Moreover, the mean SDtotaland SDMTof the DIBH group were significantly lower than that of the FB group (2.75 ± 2.33 cGy versus 4.45 cGy ± 4.33, p = 0.048) and (1.94 ± 1.63 cGy versus 3.76 ± 3.42 cGy, p = 0.007), respectively. However, there was no significant difference in the mean SDLTand SDMT-LTbetween the two groups (p > 0.05).Conclusion. In addition to the advantage of reducing the cardiopulmonary radiation doses in left breast cancer, the DIBH technique could reduce the treatment delivery uncertainty compared to the FB method due to the significant reduction in the random inter-fraction dose variations.

Development of a new Python-based cardiac phantom for myocardial SPECT imaging.

PURPOSE: The aim of this work was to develop a digital dynamic cardiac phantom able to mimic gated myocardial perfusion single photon emission computed tomography (SPECT) images. METHODS: A software code package was written to construct a cardiac digital phantom based on mathematical ellipsoidal model utilizing powerful numerical and mathematic libraries of python programing language. An ellipsoidal mathematical model was adopted to create the left ventricle geometrical volume including myocardial boundaries, left ventricular cavity, with incorporation of myocardial wall thickening and motion. Realistic myocardial count density from true patient studies was used to simulate statistical intensity variation during myocardial contraction. A combination of different levels of defect extent and severity were precisely modeled taking into consideration defect size variation during cardiac contraction. Wall thickening was also modeled taking into account the effect of partial volume. RESULTS: It has been successful to build a python-based software code that is able to model gated myocardial perfusion SPECT images with variable left ventricular volumes and ejection fraction. The recent flexibility of python programming enabled us to manipulate the shape and control the functional parameters in addition to creating variable sized-defects, extents and severities in different locations. Furthermore, the phantom code also provides different levels of image filtration mimicking those filters used in image reconstruction and their influence on image quality. Defect extent and severity were found to impact functional parameter estimation in consistence to clinical examinations. CONCLUSION: A python-based gated myocardial perfusion SPECT phantom has been successfully developed. The phantom proved to be reliable to assess cardiac software analysis tools in terms of perfusion and functional parameters. The software code is under further development and refinement so that more functionalities and features can be added.

Image quality characteristics of myocardial perfusion SPECT imaging using state-of-the-art commercial software algorithms: evaluation of 10 reconstruction methods.

Myocardial perfusion imaging (MPI) is widely used as standard of care in patients with coronary artery disease. The availability of hybrid SPECT/CT imaging system and associated advanced reconstruction algorithms serve to improve diagnostic accuracy and enhances image quality of MPI. The aim of this work was to evaluate the relative performance of iterative reconstruction algorithms correcting for different combinations of image degrading factors versus filtered back projection on the quality of myocardial perfusion SPECT imaging. A standard cardiac phantom containing myocardial defects of different sizes and compositions was used to simulate myocardial perfusion SPECT/CT clinical studies. A clinically relevant activity was determined to avoid discordance with real data acquisition. Acquisition parameters including time per projection, angular rotation increment, and iterative reconstruction number of iterations and subsets were varied. The reconstruction was carried out applying different algorithms including 10 variants of analytical (e.g FBP) and iterative reconstructions with and without resolution recovery. Typical figures of merit were used to evaluate the image quality of MPI reconstructed with ten different reconstruction methods. OSEM-RR showed remarkable improvement of image quality of MPI in terms of SNR, CNR and defect contrast percentage compared to FBP algorithm. Full correction scheme IR-RR (i.e. IRACSCRR) provides clinically acceptable image quality of MPI compared to FBP.

Correlation of texture feature analysis with bone marrow infiltration in initial staging of patients with lymphoma using 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography.

PURPOSE: To explore whether radiomic features of fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomo-graphy-computed tomography (PET/CT) has association with bone marrow infiltration (BMI) in comparison to other conventional PET metrics. MATERIAL AND METHODS: Forty-four patients (with pathologically proven lymphoma disease) underwent staging 18F-FDG PET/CT scan. Primary tumour was semi-automatically or manually segmented with a threshold standardised uptake value (SUV) of 3. A total of 73 features were extracted from eight different textures. Spearman correlation was used to test the correlation of features with conventional quantitative metrics such as SUV, metabolic tumour volume, and total lesion glycolysis. Specificity and sensitivity (including 95% confidence intervals [CI]) for each of the studied parameters were derived using receiver operative characteristic (ROC) curves. Univariate and multivariate analyses were used to identify independent predictors associated with BMI. RESULTS: Correlation between conventional PET metrics and features ranged between 0.50 and 0.97 for positive correlation (33 significant association features) and ranged from -0.52 to -0.97 for inverse correlation (three significant association features) for both strong and moderate correlations. Analysis of ROC curves showed that high-intensity long-run emphasis 4 bin, high-intensity large zone emphasis 64 bin, long-run emphasis (LRE) 64 bin, large-zone emphasis 64 bin, max spectrum 8 bin, busyness 64 bin, and code similarity 32 and 64 bin were significant discriminators of BMI among other features (area under curve > 0.682, p < 0.05). Univariate analyses of texture features showed that code similarity and long-run emphasis (both 64 bin) were significant predictors of bone marrow involvement. Multivariate analyses revealed that LRE (64 bin, p = 0.031) with an odds ratio of 1.022 and 95% CI of (1.002-1.043) were independent variables for bone marrow involvement. CONCLUSIONS: 18F-FDG PET/CT radiomic features are synergistic to visual assessment of BMI in patients diagnosed with lymphoma using 18F-FDG PET/CT. Further assessment of long-run emphasis is highly warranted.

The necessity of using deep inspiration breath-hold in the radiotherapy of left breast cancer patients who undergo the UK FAST trial.

AIM: The purpose of the current study was to compare between deep inspiration breath-hold (DIBH) and free-breathing (FB) method in the setup reproducibility and to perform a dosimetric comparison between both methods in left-sided breast cancer patients who undergo the UK FAST trial. MATERIALS AND METHODS: The online matching correction data were retrospectively collected for 50 patients treated with the FAST trial. They were equally divided into DIBH and FB groups to compare between both methods in the setup reproducibility and create the appropriate planning target volume (PTV) margin. Ten patients out of the fifty were scanned in DIBH and FB to perform a dosimetric comparison with the strict acceptance criteria of the FAST trial. RESULTS: All heart dosimetric parameters of the DIBH was significantly lower than that of FB (p < 0.001), and the lung V30% of DIBH plans was significantly lower than FB plans (p = 0.03). There was no statistically significant difference between the two methods in the other organs at risk doses. To fulfill the heart and lung constraints in FB plans, the PTV V90% was reduced by 3.4%, and three plans would not attain the PTV acceptance criteria. There was no significant difference between the systematic or random setup errors between both methods except the left-right random shift was significantly lower in DIBH cases (p = 0.004). The calculated PTV margins were (4 mm, 3 mm, and 4 mm) for DIBH group, and (5 mm, 6 mm, and 8 mm) for FB group in the anterior-posterior, superior-inferior, and left-right shifts, respectively. CONCLUSION: It is highly warranted to treat left-sided breast cancer patients with the DIBH technique when the UK FAST trial is employed for treatment.

New synthetic chitosan hybrids bearing some heterocyclic moieties with potential activity as anticancer and apoptosis inducers.

Wastes of the freshwater crayfish Procambarus clarkii were used as precursor for the extraction of chitin, which was deacetylation with alkali giving chitosan. Chitosan was transformed into the nanoparticles using sodium tripolyphosphate. Chitosan Cs and its nanoparticles CNP were characterized through FTIR, 1H NMR and surface morphology. Moreover, it was converted into some chitosan Schiff bases; CSB-1,2,3, containing different five membered heterocyclic moieties and also they were characterized. All of the synthesized compounds were evaluated against three cell lines, such as HepG-2, HCT-116 and MCF-7, whereas compounds CSB-2 and CSB-3 showed the highest cytotoxic activities. The higher activities for the latter compounds were confirmed through apoptosis studies (Caspase-3 and Bax/Bcl-2 ratio) against HePG-2 cells. Cell cycle analysis and apoptosis induction showed that compound CSB-2 induces apoptosis at pre G1 phase and cell growth arrest at G2/M phase.

OCCUPATIONAL RADIATION DOSE TO NUCLEAR MEDICINE STAFF DUE TO TC99M, F18-FDG PET AND THERAPEUTIC I-131 BASED EXAMINATIONS.

The aim was to track the exposure to radiation workers in six nuclear medicine examinations. A number of 180 patients were recruited and external exposure was measured. Patients had undergone cardiac stress and rest, bone scan, I-131 therapy, Gallium-67 and FDG PET/CT imaging. The average dose received due to cardiac stress and rest were 20.4 ± 5.0 and 16.0 ± 3.8 µSv per patient, respectively, whereas for bone scan, Ga-67, FDG and I-131 therapy, the average dose was 6.1 ± 2.5, 6.0 ± 1.4, 11.1 ± 2.2 and 4.1 ± 2.6 µSv per patient. The patient-to-staff dose coefficients were on average 0.051 ± 0.009, 0.042 ± 0.010, 0.034 ± 0.016, 0.039 ± 0.021, 0.052 ± 0.012, 0.094 ± 0.021 µSv m2/MBq h for stress, rest, bone, I-131, Ga-67 and FDG reported post-administration, respectively. Patient injection and setup for imaging represent a high percentage of the total dose received by staff. The information revealed is able to revise local measures, safety standards, and could help further in dose optimization and minimal exposure to occupationally exposed worker in nuclear medicine laboratories.