Dose Values Research Articles

The effect of incidental dose to pelvic nodes in bladder-only irradiation in the era of IMRT: adosimetric study.

While three-dimensional radiotherapy (RT) causes high incidental nodal doses in bladder-only irradiation for muscle-invasive bladder cancer (MIBC), the impact on pelvic lymphatics is unclear in the era of intensity-modulated RT (IMRT). This study evaluates incidental doses to pelvic lymphatics in MIBC patients treated with IMRT. The data of 40MIBC patients treated with bladder-only IMRT and concurrent chemotherapy were retrospectively evaluated. The pelvic lymphatics were contoured on initial simulation images and incidental nodal doses were evaluated. The Statistical Package for the Social Sciences (SPSS) version23.0 (IBM, Armonk, NY, USA) was used for statistics. Median RT dose to the bladder was 60 Gy in 30fractions. In dosimetric analysis, median values of mean dose (Dmean) of the obturator, presacral, external iliac, internal iliac, and distal common iliac lymphatics were 33 Gy (range 4-50 Gy), 3 Gy (range 1-28 Gy), 9.5 Gy (range 3-41 Gy), 7.5 Gy (range 2-14 Gy), and 1 Gy (range 0-15 Gy), respectively. The Dmean of the obturator lymphatics was significantly higher (p < 0.001) and the Dmean of the distal common iliac lymphatics was significantly lower (p < 0.001) than all remaining lymphatic stations. The Dmean of the external iliac lymphatics was significantly higher than that of the presacral lymphatics (p < 0.001), but the difference with the internal iliac lymphatics was not statistically significant (p = 0.563). The incidental nodal doses with bladder-only IMRT are heterogeneous and remain below the generally accepted doses for microscopic disease eradication for bladder cancer.

A dose of nature to reduce sexual crimes in public outdoor spaces: Proposing the Landscape-Sexual Crime Model

Sexual crime is a critical global social problem. There remains a critical knowledge gap concerning whether and to what extent sexual crimes in public outdoor spaces can be influenced by landscape morphology of green spaces. This missing knowledge hinders the effective use of green spaces to reduce sexual crimes in these public settings. To address this issue, we collected a dataset comprising 5,155 cases of sexual crimes that occurred in public outdoor spaces in the United States from August 2021 to July 2022. A random forest model was employed to examine the statistical relationships between landscape morphology and sexual crimes. Additionally, we utilized the Shapley Additive Explanations (SHAP) model to quantify the interaction effects of landscape morphology with socioeconomic and demographic characteristics. This study yields three key findings: (1) Both the proportion and configuration factors of landscape morphology may significantly influence the sexual crime probability. (2) The relationships between landscape morphology and sexual crimes are nonlinear, and threshold values for the satisfactory dose and the preferred dose of green spaces can be identified. (3) There are significant interaction effects between landscape morphology with socioeconomic and demographic characteristics, emphasizing the importance of prioritizing green space interventions in socioeconomically disadvantaged areas. Lastly, through summarizing the findings of this study and previous research, we propose the Landscape-Sexual Crime Model (LSCM), which advocates for further research to explore effective strategies for using green spaces to reduce sexual crimes.

Evolution of dose distribution for a 125I eye plaque using MCNPX and Plaque Simulator software

AbstractObjectiveEye plaque radiation therapy is the treatment of choice for small‐ and medium‐sized choroidal melanomas. This study investigated the dose distribution around eye plaques containing 125I seeds to treat ocular melanoma using Monte Carlo N‐Particle eXtended (MCNPX) and Plaque Simulator (PS) software.MethodsDosimetry evaluation and comparison of the resulting isodose curves for 125I COMS plaques were performed using the MCNPX code. The isodose curves and dose distributions were calculated using PS treatment planning for a 125I COMS plaque.ResultsIn the validation, the maximum relative difference between the results of this study and those reported in other literature was approximately 9%–10% for the COMS plaques. The dose distributions of MCNPX were lower than those of PS with a relative difference of approximately 27.7%–35.4%. The dose distribution may differ depending on the 125I source spectra and seed design used in the two methods. In addition, the dose algorithm used in PS made a major contribution to the relative differences between the results.ConclusionThe PS did not provide accurate details of dose distribution near the surface of the plaque insert. The source parameters used in each program should be studied more carefully to determine the source of the differences in the estimated dose values.

Development and verification of an electron Monte Carlo engine for applications in intraoperative radiation therapy.

In preparation of future clinical trials employing the Mobetron electron linear accelerator to deliver FLASH Intraoperative Radiation Therapy (IORT), the development of a Monte Carlo (MC)-based framework for dose calculation was required. To extend and validate the in-house developed fast MC dose engine MonteRay (MR) for future clinical applications in IORT. MR is a CPU MC dose calculation engine written in C++ that is capable of simulating therapeutic proton, helium, and carbon ion beams. In this work, development steps are taken to include electrons and photons in MR are presented. To assess MRs accuracy, MR generated simulation results were compared against FLUKA predictions in water, in presence of heterogeneities as well as in an anthropomorphic phantom. Additionally, dosimetric data has been acquired to evaluate MRs accuracy in predicting dose-distributions generated by the Mobetron accelerator. Runtimes of MR were evaluated against those of the general-purpose MC code FLUKA on standard benchmark problems. MR generated dose distributions for electron beams incident on a water phantom match corresponding FLUKA calculated distributions within 2.3% with range values matching within 0.01mm. In terms of dosimetric validation, differences between MR calculated and measured dose values were below 3% for almost all investigated positions within the water phantom. Gamma passing rate (1%/1mm) for the scenarios with inhomogeneities and gamma passing rate (3%/2mm) with the anthropomorphic phantom, were>99.8% and 99.4%, respectively. The average dose differences between MR (FLUKA) and the measurements was 1.26% (1.09%). Deviations between MR and FLUKA were well within 1.5% for all investigated depths and 0.6% on average. In terms of runtime, MR achieved a speedup against reference FLUKA simulations of about 13 for 10 MeV electrons. Validations against general purpose MC code FLUKA predictions and experimental dosimetric data have proven the validity of the physical models implemented in MR for IORT applications. Extending the work presented here, MR will be interfaced with external biophysical models to allow accurate FLASH biological dose predictions in IORT.

Structure of irradiated polymer in semi dilute regime concentration: roles of dose values

Structure of irradiated polymer in semi dilute regime concentration: roles of dose values

Attention 3D U-NET for dose distribution prediction of high-dose-rate brachytherapy of cervical cancer: Direction modulated brachytherapy tandem applicator.

Direction Modulated Brachytherapy (DMBT) enables conformal dose distributions. However, clinicians may face challenges in creating viable treatment plans within a fast-paced clinical setting, especially for a novel technology like DMBT, where cumulative clinical experience is limited. Deep learning-based dose prediction methods have emerged as effective tools for enhancing efficiency. To develop a voxel-wise dose prediction model using an attention-gating mechanism and a 3D UNET for cervical cancer high-dose-rate (HDR) brachytherapy treatment planning with DMBT six-groove tandems with ovoids or ring applicators. A multi-institutional cohort of 122 retrospective clinical HDR brachytherapy plans treated to a prescription dose in the range of 4.8-7.0Gy/fraction was used. A DMBT tandem model was constructed and incorporated onto a research version of BrachyVision Treatment Planning System (BV-TPS) as a 3D solid model applicator and retrospectively re-planned all cases by seasoned experts. Those plans were randomly divided into 64:16:20 as training, validating, and testing cohorts, respectively. Data augmentation was applied to the training and validation sets to increase the size by a factor of 4. An attention-gated 3D UNET architecture model was developed to predict full 3D dose distributions based on high-risk clinical target volume (CTVHR) and organs at risk (OARs) contour information. The model was trained using the mean absolute error loss function, Adam optimization algorithm, a learning rate of 0.001, 250 epochs, and a batch size of eight. In addition, a baseline UNET model was trained similarly for comparison. The model performance was evaluated on the testing dataset by analyzing the outcomes in terms of mean dose values and derived dose-volume-histogram indices from 3D dose distributions and comparing the generated dose distributions against the ground-truth dose distributions using dose statistics and clinically meaningful dosimetric indices. The proposed attention-gated 3D UNET model showed competitive accuracy in predicting 3D dose distributions that closely resemble the ground-truth dose distributions. The average values of the mean absolute errors were 1.82±29.09Gy (vs. 6.41±20.16Gy for a baseline UNET) in CTVHR, 0.89±1.25Gy (vs. 0.94±3.96Gy for a baseline UNET) in the bladder, 0.33±0.67Gy (vs. 0.53±1.66Gy for a baseline UNET) in the rectum, and 0.55±1.57Gy (vs. 0.76±2.89Gy for a baseline UNET) in the sigmoid. The results showed that the mean absolute error (MAE) for the bladder, rectum, and sigmoid were 0.22±1.22Gy (3.62%) (p=0.015), 0.21±1.06Gy (2.20%) (p=0.172), and -0.03±0.54Gy (1.13%) (p=0.774), respectively. The MAE for D90, V100%, and V150% of the CTVHR were 0.46±2.44Gy (8.14%) (p=0.018), 0.57±11.25% (5.23%) (p=0.283), and -0.43±19.36% (4.62%) (p=0.190), respectively. The proposed model needs less than 5 s to predict a full 3D dose distribution of 64×64×64 voxels for any new patient plan, thus making it sufficient for near real-time applications and aiding with decision-making in the clinic. Attention gated 3D-UNET model demonstrated a capability in predicting voxel-wise dose prediction, in comparison to 3D UNET, for DMBT intracavitary brachytherapy planning. The proposed model could be used to obtain dose distributions for near real-time decision-making before DMBT planning and quality assurance. This will guide future automated planning, making the workflow more efficient and clinically viable.

The effect of L-Arginine therapy on achilles tendon healing: A histological and biomechanical investigation in an animal model

PurposeSeveral clinical and experimental studies have revealed that L-Arginine, which has antioxidant properties, accelerates tissue healing. This study examined the in vivo effects of oral L - Arginine supplementation on tendon regeneration in Wistar rats. MethodFor each weighting of an average of 250–300 g, 24 Wistar rats were separated into three equal groups. Each rat's right hind leg Achilles tendons were tenotomized and then repaired. The first group (Control) was followed up with a regimen of standard food and water. In the second group (L-Arg Low Dose), 300 mg/kg, and in the third group (L-Arg High Dose), 600 mg/kg L-Arginine was administered in water daily with a regimen of standard food and water ad libitum. After eight weeks, the rats were sacrificed, and the tendons were histologically and biomechanically analyzed. ResultsTendon peak strength values of the L-Arg Low Dose and L-Arg High Dose groups were similar but significantly higher than the control group. A statistically significant difference was observed between the groups in terms of ground substance, fiber arrangement, cellularity, hyalinization, and GAG properties ( p = 0.05, p = 0.002, p = 0.016, p = 0.027, p = 0.05). There was no statistically significant difference between the groups according to the histological examination of collagen properties, fiber structure, tenocyte properties, rounding of the nuclei, and collagen stainability. (p = 0.999, p = 0.061, p = 0.195, p = 0.195, p = 0.130). No mortality, wound complications, or re-ruptures were observed. ConclusionCompared with the control group, histologically and biomechanically distinct therapeutic effects of L-Arginine supplementation on tendon healing were determined. Level of clinical evidence5

Phytochemical and pharmacological profiling of extracts of Pterygota alata (Roxb.) R. Br. leaves deciphered therapeutic potentialities against pain, hyperglycemia and diarrhea via in vivo approaches

Background and aimPterygota alata (Roxb.) R. Br. is a large, broad-leaved evergreen plant in the family Malvaceae (formerly Sterculiaceae). The present study aimed to investigate the phytochemical and pharmacological properties of methanolic extract of the leaves (200 mg/kg bw and 400 mg/kg bw) of P. alata focusing on analgesic, hypoglycemic, and anti-diarrheal potentials on the Swiss Albino mice model. MethodsGas chromatography and mass spectrometry (GC-MS) technique was employed to identify the bioactive compounds from the plant species. The tail flicking procedure and acetic acid-induced writhing inhibition were carried out to estimate central and peripheral analgesic properties. The anti-diarrheal property of the herbaceous extractive was assessed employing the castor oil-induced antidiarrheal approach, while the hypoglycemia was estimated employing the tail-tipping method. ResultsThe study reported a total of thirty-seven phytoconstituents by using GC-MS analysis, where erucamide (25.5 %), 8,11,14-Docosatrienoic acid, methyl ester (14.58 %), methyl linoleate (12.67 %), and methyl palmitate (9.23 %) were most abundant in the plant species. In evaluating central analgesia, the leaf extract of P. alata exerted significant central analgesic (200 mg/kg bw and 400 mg/kg bw) efficacy. The acetic acid-induced writhing was inhibited by 45.84 % and 66.67 % at both doses, demonstrating a promising peripheral analgesic effect compared to diclofenac sodium (75.00 %). On the contrary, hypoglycemic actions remained dosage and time-dependent. In the antidiarrheal activity assay, the number of diarrheal feces was reduced significantly by 40.00 % (200 mg/kg) and 68.00 % (400 mg/kg), correspondingly, which was comparable to the positive control loperamide (72.00 %). In addition, the study of acute oral toxicity revealed that the extracts of the plant species were found to be safe, with a median lethal dose (LD50) value greater than 1000 mg/kg. ConclusionThe current study supports the assertion that the P. alata plant species is rich in numerous phytoconstituents and has the potential for traditional application in managing pain, hyperglycemia, and diarrhea. Nonetheless, additional investigation is necessary to extract and identify the bioactive compounds from the plant, which is crucial for advancing the discovery of novel medicinal compounds aimed at addressing a range of health conditions.

Distribution of natural radioactivity in different geological formations and their environmental risk assessment in Malaysia

Labuan, Miri, Kundasang and Raub regions of Malaysia have very different geological formations and settings that could result in different levels of natural radioactivity. Hence, this study determines the influence of different geological formations on radioactivity in these locations using field measurements, petrology and geochemistry. A total of 141 gamma dose rates and 227 beta flux measurements were collected using Polimaster survey meters (PM1405) in these four regions. The gamma dose rate values range from 0.37 to 0.05 µSv/h with a mean value of 0.11 µSv/h. Beta flux values range from 3.46 to 0.12 CPS with a mean value of 0.57 CPS. Mineralogy and elemental composition of the different rock types were analysed using thin-section petrography, XRD, ICP and pXRF methods. Felsic igneous rocks such as syenite and granite have higher natural radioactivity and contain more radionuclide-bearing minerals such as apatite, zircon, allanite, K-feldspar, titanite, muscovite and biotite. Metamorphic rocks have the second highest natural radioactivity and contain fewer radioactive minerals. The natural radioactivity of sedimentary rocks mostly depends on their clay content. The gamma dose rate maps show that igneous and metamorphic regions around Raub have higher radioactivity compared to the sedimentary-dominated regions around Miri and Labuan. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated to evaluate the potential health risk for inhabitants of these regions. Labuan and Miri are considered to be safe zones with respect to natural radioactivity as the results show little to no risk for the public, compared with the Raub region, which is medium to high risk.

Evaluation of Effective Doses of Radiation and Risk Factors in Thorax-Testing CT Scans of Patients with Lung Cancer Cases

Abstract Human organs have a certain dose tolerance to receive X-ray radiation, one of which can be received from radiodiagnostic radiation using a CT scan. The aim of this research is study to estimate the effective dose received by CT scan thorax patients then compare it with the Dose Limit Value (DLV) advised by the Nuclear Energy Regulatory Agency (BAPETEN). An estimated effective dose value can be created by calculating the dosage that an organ got from radiation during irradiation using a CT scan. IndoseCT v20b software and manual calculations using empirical tissue weight factors are used in this study to estimate the effective dose received by CT scan thorax patients. This estimated effective dose is then compared with the Dose Limit Value (DLV) advised by the Nuclear Energy Regulatory Agency (BAPETEN) for CT scan thorax patients. The effective dose also can be used to identify cancer risk factors as well as organs at risk in the chest cavity. The basic patient data for this study, including the computed tomography dose index vol (CTDIvol) and dose length product (DLP) values, were collected through observation. Then, on the basis of patient data from a thorax CT scan, data processing was done using the IndoQCT and IndoseCT v20b software programs as well as manual calculations utilizing empirical tissue weight factors. According to this information, the patient who received the greatest effective dose according to calculations made manually and using the IndoseCT program was 38.61 mSv and 35.75 mSv. The results of this study show that the both effective dose value from the two calculation results is still below the DLV recommended by BAPETEN so it is acceptable and considered safe for patients. The thymus gland, heart, and trachea-bronchi are the three organs that receive the highest effective dose values, which increases the possibility of damage after CT scan of the thorax in patients.

Children's exposure to halogenated flame retardants and organophosphate esters through dermal absorption and hand-to-mouth ingestion in Swedish preschools

Children are exposed to endocrine disrupting chemicals (EDCs) through inhalation and ingestion, as well as through dermal contact in their everyday indoor environments. The dermal loadings of EDCs may contribute significantly to children's total EDC exposure due to dermal absorption as well as hand-to-mouth behaviors. The aim of this study was to measure potential EDCs, specifically halogenated flame retardants (HFRs) and organophosphate esters (OPEs), on children's hands during preschool attendance and to assess possible determinants of exposure in preschool indoor environments in Sweden. For this, 115 handwipe samples were collected in winter and spring from 60 participating children (arithmetic mean age 4.5 years, standard deviation 1.0) and analyzed for 50 compounds. Out of these, 31 compounds were identified in the majority of samples. Levels were generally several orders of magnitude higher for OPEs than HFRs, and 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected in the highest median masses, 61 and 56 ng/wipe, respectively. Of the HFRs, bis(2-ethyl-1-hexyl)-2,3,4,5-tetrabromobenzoate (BEH-TEBP) and 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) were detected in the highest median masses, 2.8 and 1.8 ng/wipe, respectively.HFR and/or OPE levels were found to be affected by the number of plastic toys, and electrical and electronic devices, season, municipality, as well as building and/or renovation before/after 2004. Yet, the calculated health risks for single compounds were below available reference dose values for exposure through dermal uptake as well as for ingestion using mean hand-to-mouth contact rate. However, assuming a high hand-to-mouth contact rate, at the 95th percentile, the calculated hazard quotient was above 1 for the maximum handwipe mass of TBOEP found in this study, suggesting a risk of negative health effects. Furthermore, considering additive effects from similar compounds, the results of this study indicate potential concern if additional exposure from other routes is as high.

Diagnostic reference levels in spinal CT: Jordanian assessments and global benchmarks.

To reduce radiation dose and subsequent risks, several legislative documents in different countries describe the need for Diagnostic Reference Levels (DRLs). Spinal radiography is a common and high-dose examination. Therefore, the aim of this work was to establish the DRL for Computed Tomography (CT) examinations of the spine in healthcare institutions across Jordan. Data was retrieved from the picture archiving and communications system (PACS), which included the CT Dose Index (CTDI(vol)) and Dose Length Product (DLP). The median radiation dose values of the dosimetric indices were calculated for each site. DRL values were defined as the 75th percentile distribution of the median CTDI(vol) and DLP values. Data was collected from 659 CT examinations (316 cervical spine and 343 lumbar-sacral spine). Of the participants, 68% were males, and the patients' mean weight was 69.7 kg (minimum = 60; maximum = 80, SD = 8.9). The 75th percentile for the DLP of cervical and LS-spine CT scans in Jordan were 565.2 and 967.7 mGy.cm, respectively. This research demonstrates a wide range of variability in CTDI(vol) and DLP values for spinal CT examinations; these variations were associated with the acquisition protocol and highlight the need to optimize radiation dose in spinal CT examinations.

Analisis Tingkat Paparan Radiasi Di Area Tiroid Dokter Kardiologi Intervensi Selama Pemeriksaan Diagnostik Percutaneous Coronary Intervention (PCI) Di Ruang Cath Lab RSUD dr Soedarso Pontianak

Background: Analysis of Radiation Exposure Levels in the Thyroid Area of ​​Interventional Cardiology Doctors During Percutaneous Coronary Intervention (PCI) Diagnostic Examinations in the Cath Lab Room at Dr Soedarso Pontianak Hospital, is research related to patient examinations in the Percutaneous Coronary Intervention Diagnostic Room. The main object in this research is the doctor who examines or treats patients in the room. Researchers wanted to see how many doses of radiation exposure were received by officers examining patients. Method: The research used in this research is quantitative methods. Quantitative research is research that emphasizes analysis on numerical data processed using statistical methods. Based on the type of research, this quantitative research leads to analytical (inferential) research, namely analyzing the relationship between variables by testing hypotheses. The object of focus in this research is an Interventional Cardiology doctor, using 30 patients who have received treatment from a doctor in the cath lab room then the data analysis process uses the measurement results from the pen dose, by conducting research for ten days from 10 August 2023 - 17 August 2023 Results: The results obtained from the average value of radiation dose exposure received by Dr. Interventional Cardiology in the Cath Lab Room at Dr. Soedarso Pontianak Hospital while examining 30 patients, were 0 Sv or the equivalent of 0.000 mSv. Based on these results, it was concluded that the PPE used in the cath lab room at Soedarso Regional Hospital was in accordance with applicable regulations. Conclusion: Based on the data that has been analyzed, it can be concluded that the average value of radiation dose exposure received by Dr. Interventional Cardiology in the Cath Lab Room at Dr. Soedarso Pontianak Hospital while examining 30 patients, is 0 Sv, and is equivalent to 0.000 mSv. Based on the average value of the exposure dose received, which is 0 Sv, the PPE used can reduce the radiation exposure received by doctors. The personal protective equipment includes: Hat, Google Glasses, Thyroid, Apron and protective screen used in accordance with applicable regulations can reduce radiation exposure received by cardiology doctors in the cath lab room at Dr Soedarso Hospital Pontianak.

Antiviral Activity of Physta®, Standardised Water Extract of Eurycoma longifolia against SARS-CoV-2: An in vitro Study

Eurycoma longifolia Jack (Simaroubaceae) root extract is known to exhibit antiinflammatory, antiviral and immunomodulatory activities. Therefore, E. longifolia, through a multimodal approach could potentially be used in COVID-19 management. However, to date there has been no investigation into the antiviral activity of E. longifolia root extract against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The objective of the study is to investigate the antiviral activity of Physta® (a standardised water extract of E. longifolia) against SARS-CoV-2. A mitochondrial metabolic activity assay using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) was used to determine the cytotoxicity of the Physta® extract in Vero cells, with concentrations ranging from 1.95 µg/mL to 1,000 µg/mL. Physta® was tested for antiviral activity at six different concentrations, ranging from 3.12 µg/mL to 50 µg/mL. The half maximal cytotoxic concentration (CC50) value of Physta® against Vero cells was estimated at 1,117 µg/mL and the maximum non-toxic dose (MNTD) value was estimated at 60 µg/mL. Physta® inhibited SARS-CoV-2 replication in a dose-dependent manner, and the half maximal inhibition concentration (IC50) was estimated to be 36.3 µg/mL. This study has demonstrated the antiviral activity of Physta® against SARS-CoV-2. Future evaluations in animal and clinical settings should be conducted to determine whether Physta® can be used alone or in combination with other antiviral agents to alleviate COVID-19.

Shielding design and analysis of the hot cell used to produce fission molybdenum-99

Molybdenum-99 is a critical radioisotope for producing diagnostic radiopharmaceuticals labeled by technetium-99m. In this study, the shielding of hot cells used in radiochemical process facilities for industrial 99Mo production via fission of domestic LEU targets was investigated. A calculation method based on MCNP6 simulations was proposed and evaluated by some experimental data. The results showed that the calculated dose rate values should be multiplied by 1.3 from a conservative point of view and then values compared with the permissible dose rate limits. The ISODOSE graphs showed that although a one-layer hot cell with Barite concrete (BA) walls of 80 cm is not enough for radiation-safe work on a hot batch, a one-layer hot cell of BA with 90 cm walls, two-layer BA(80 cm) + Lead(3 cm) and BA(80 cm) + Carbon steel (CS) (4.3 cm) and three-layer BA(80 cm) + CS(1.4 cm) + Lead(2 cm) could be suitable options.

Digital phantom versus patient-specific radiation dosimetry in adult routine thorax CT examinations.

The aim of this study was to compare the organ doses assessed through a digital phantom-based and a patient specific-based dosimetric tool in adult routine thorax computed tomography (CT) examinations with reference to physical dose measurements performed in anthropomorphic phantoms. Two Monte Carlo based dose calculation tools were used to assess organ doses in routine adult thorax CT examinations. These were a digital phantom-based dosimetry tool (NCICT, National Cancer Institute, USA) and a patient-specific individualized dosimetry tool (ImpactMC, CT Imaging GmbH, Germany). Digital phantoms and patients were classified in four groups according to their water equivalent diameter (Dw). Normalized to volume computed tomography dose index (CTDIvol), organ dose was assessed for lungs, esophagus, heart, breast, active bone marrow, and skin. Organ doses were compared to measurements performed using thermoluminescent detectors (TLDs) in two physical anthropomorphic phantoms that simulate the average adult individual as a male (Alderson Research Labs, USA) and as a female (ATOM Phantoms, USA). The average percent difference of NCICT to TLD and ImpactMC to TLD dose measurements across all organs in both sexes was 13% and 6%, respectively. The average±1 standard deviation in dose values across all organs with NCICT, ImpactMC, and TLDs was±0.06 (mGy/mGy),±0.19 (mGy/mGy), and±0.13 (mGy/mGy), respectively. Organ doses decreased with increasing Dw in both NCICT and ImpactMC. Organ doses estimated with ImpactMC were in closer agreement to TLDs compared to NCICT. This may be attributed to the inherent property of ImpactMC methodology to generate phantoms that resemble the realistic anatomy of the examined patient as opposed to NCICT methodology that incorporates an anatomical discrepancy between phantoms and patients.

Analysis of ionizing radiation doses received by patients during electrocardiological procedures

Medical procedures in the field of electrocardiology belong to a large group of cardiological procedures. Performing them involves exposure to ionizing radiation. In this study, five medical procedures in the field of electrocardiology performed in three medical facilities were analyzed in terms of patients’ exposure to ionizing radiation. A total of 178 patients were analyzed. Depending on the type of procedure, the recorded doses ranged from 7.4 to 614.62 mGy. The majority of electrocardiological procedures are pacemaker implantations 38% and RF ablation 33%. The results obtained show a significant dispersion of the recorded dose values in the same type of treatment. This is reflected, for example, in the high coefficient of variation for doses in RF ablation. The type of X-ray machine used during the procedure also influences the dose values. Although the exposure of patients undergoing electrocardiological procedures to ionizing radiation is much lower than in the case of cardiac vascular procedures, it may reach a similar level, especially in the case of implantation of devices regulating the correct functioning of the heart.

Comparison of pediatric lens scattered dose measurements between axial 40-mmand helical 160-mmdetector widthcomputed tomographyscan modes.

Reports comparing field lens doses between helical scans with a 40-mm detector width and axial scans with a 160-mm detector width using different computed tomography (CT) scanners are currently scarce. To compare scatter doses for lenses between a helical scan with a 40-mm detector width and an axial scan with a 160-mm detector width when using different CT scanners in the context of pediatric chest examinations. Two different CT machines were used: Revolution CT (GE Healthcare, Waukesha, WI) with a 256-row, 0.625-mm multidetector; and Aquilion ONE GENESIS Edition (Canon Medical Systems, Otawara, Japan) with a 320-row, 0.5-mm multidetector. Three pediatric anthropomorphic phantoms were used, with optically stimulated luminescence dosimeters (OSLDs) placed on the left and right lenses. The scatter dose values measured by the OSLDs were compared between a helical scan with a 40-mm detector width and an axial scan with a 160-mm detector width during pediatric chest CT examinations. Median equivalent doses for the helical and axial scans were 0.12 and 0.12 mSv/mGy for the newborn, 0.17 and 0.16 mSv/mGy for the 1-year-old, and 0.18 and 0.15 mSv/mGy for the 5-year-old, respectively, when using the Revolution CT. With the Revolution CT, no significant differences were observed in the scatter doses between helical and axial scans in the newborn and 1-year-old phantoms. However, the lens scatter dose for the helical scan was approximately 20-35% higher than that for the axial scan in the 5-year-old phantom (P<0.01). The median equivalent doses of eye lenses for the helical and axial scans were 0.12 and 0.07 mSv/mGy for the newborn, 0.07 and 0.05 mSv/mGy for the 1-year-old, and 0.14 and 0.12 mSv/mGy for the 5-year-old, respectively, when using the Aquilion ONE. With the Aquilion ONE, lens scatter doses for the helical scan were approximately 70%, 40%, and 30% higher in the newborn, 1-year-old, and 5-year-old phantoms, respectively, than those for the axial scan (P<0.01). When using the Aquilion ONE, lens scatter doses for the helical scan were significantly higher in all three phantoms than those for the axial scan. In contrast, when using the Revolution CT, the lens scatter dose for the helical scan was significantly higher in the 5-year-old phantom than that for the axial scan. These results suggest that although scattered doses may vary with respect to the CT scanner and body size, they are generally lower in the case of axial scans.

The role and function mechanism of tapP in modulating the virulence of Aeromonas hydrophila

Aeromonas hydrophila (A. hydrophila) is a widespread pathogen capable of infecting most freshwater fish and causing septicemia. Type IV pili are one of the major virulence factors of A. hydrophila and play a key role in virulence and adhesion to the host. TapP is known to be involved in the synthesis of type IV pili. However, the effect and molecular mechanism of the tapP in A. hydrophila remain unknown. In this study, we constructed a genetically stable tapP deletion mutant strain of A. hydrophila (ΔtapP-AH), the median lethal dose (LD50) value of the ΔtapP-AH in Carassius auratus gibelio was 3.1-fold higher than that of the wild-type strain (WT-AH). The transmission electron microscopy (TEM) results showed that ΔtapP-AH exhibited sparser pili. The ability of adhering to gill tissues and biofilm formation was significantly reduced in ΔtapP-AH. For motility, the swimming ability of ΔtapP-AH was significantly higher, no significant difference was found in twitching and swarming abilities. We further investigated the effect of tapP gene deletion on the expression of virulence related factor genes to explore the molecular mechanisms of attenuated virulence and altered biological characteristics. The results indicated that deletion of the tapP directly affected the expression of genes related to type IV pili, type II secretion system, type VI secretion system and flagellum, but had no effect on the genes related to type I pili. In conclusion, this study provides new insights into the function of the tapP and the pathogenic mechanism in A. hydrophila.

The correlation between chemical ingredients and acute toxicity of Psoraleae Fructus and two classic prescriptions

Objective: To compare the acute toxicity and chemical ingredients of Psoraleae Fructus (PF) with those of two classic prescriptions, Ershen Wan (ESW) and Sishen Wan (SSW). Methods: Based on classical toxicological methods, body weight, food and water consumption, lethal conditions, and toxic reactions were recorded after administering single oral doses of PF, ESW, and SSW. The 50% lethal dose (LD50) values of PF and ESW and the maximum tolerance dose (MTD) of SSW were determined. In addition, PF, ESW, and SSW constituents were detected using ultra-high-performance liquid chromatography/mass spectrometry (UPLC-MS), and the spectrum-toxicity correlation was analyzed. Results: The LD50 of PF and ESW were 53.9 g/kg/day (46.2–63.0 g/kg/day, 95% confidence limit [CL]) and 68.3 g/kg/day (59.0–78.9 g/kg/day, 95% CL), which were respectively about 40 and 50 times the human daily dosage. The MTD of SSW was 41.0 g/kg/day, indicating the highest safety. What can be inferred from the chemical ingredients and toxicity correlation analyses is that compatibility reduced the contents of 13 potential hepatotoxin compounds in PF. Conclusions: The classic compatibility of ESW and SSW effectively attenuated the hepatotoxicity of PF, which was related to the reduced content of potentially toxic substances, particularly coumarins. This study explored the principles of attenuating the toxicity of classic prescriptions to provide a reference for the rational clinical use of PF.