Radiological Sciences Research Articles

Experimental Transverse Beam Emittance Measurement Using Solenoid Magnet Strength Variation in AB-BNCT

Boron neutron capture therapy (BNCT) is a more efficient cancer treatment method compared to direct radiation therapy using charged particles such as protons or carbon beams. Particularly, accelerator-based BNCT (AB-BNCT) is attracting attention due to easy construction in a hospital. The Korea Institute of Radiological & Medical Sciences (KIRAMS) has constructed an injection system for an electrostatic AB-BNCT accelerator and commissioned 30 keV H− and 5 keV D− ion beam facilities. The beam characteristic parameters and Twiss parameters should be confirmed experimentally, and various methods have to be applied for the related measurements. In this study, the linear matrix formalism is used as a technique to measure the beam characteristic and Twiss parameters by varying the magnetic field strength of a solenoid in the beam line. To confirm the validity of this method, a multi-particle tracking code was executed. The simulation results confirm that the proposed method is effective for extracting Twiss parameters. After verification via the multi-particle tracking code, the method was applied to perform experimental measurements. Notably, the method accurately obtains the transverse beam emittance within reasonable uncertainty levels. Thus, our results show that the proposed method is a convenient technique for extracting the Twiss parameters indirectly. The results of the Twiss parameter measurement can potentially be more precise if other aspects, such as the quadrupole magnetic field strength, are incorporated.

Absorbed dose to water standard for 192Ir HDR sources using Fricke Dosimetry

The Fricke solution is a chemical dosimeter that is based on the oxidation of ferrous ions to ferric ions in the solution after interaction with ionizing radiation. It is composed of 96% water (by weight), and its density is thus remarkably similar to that of water. In addition, studies show that the Fricke dosimeter can be used as a primary dosimeter in the determination of the absorbed dose to water for high dose rate (HDR) 192Ir brachytherapy. The Radiological Sciences Laboratory of the University of Rio de Janeiro State (LCR/UERJ) has been investigating the use of the Fricke dosimeter in various applications for more than ten years, particularly in the area of radiotherapy. This review paper presents important improvements in recent years by the LCR/UERJ in the determination of the absorbed dose to water for 192Ir sources. This includes a newly designed irradiation vessel, a new reading device, a description of the need for careful temperature control during irradiation and reading, a more accurate calculation of the correction factors and the results of an intercomparison with the National Calibration Laboratory of Canada. Careful preparation of the Fricke solution is one of the most critical steps in the process. Over the years, the LCR/UERJ has tested different methods of preparing the solution and the final procedure is presented. Regarding the irradiation vessel, a molded double-walled, spherical flask for the Fricke solution was first constructed and used to measure the absorbed dose to water. However, as it was difficult to manipulate the spherical flask, a second design also made with PMMA was molded as a cylinder, with a central tube where the source was centrally positioned. Different methodologies have been reported in the determination of the G-value, a key parameter in Fricke dosimetry, and herein, two different methodologies used by the LCR are reviewed. For the absorbed-dose-to-water determination for 192Ir sources, the overall combined uncertainty associated with the measurements is estimated to be less than 1% for k = 1. Thus, the obtained uncertainties for the determination of the absorbed dose to water using Fricke dosimetry are lower than those obtained using the standard protocols. With respect to clinical practice, this could improve the accuracy in the calculation of the dose delivered to the patients. Overall, the results show that Fricke dosimetry is a reliable system to measure absorbed dose to water as a standard for HDR 192Ir.

The strategy to develop newly joined radiographers in a COVID-19 world: a curated orientation programme

The strategy to develop newly joined radiographers in a COVID-19 world: a curated orientation programme

Prevalence of Malignancy and Histopathological Association of Bosniak Classification, Version 2019 Class III and IV Cystic Renal Masses

Bosniak Classification, version 2019 (v2019) describes 2 types of class III and IV masses each: 1) thick, wall/septa ≥4 mm (III-WS), 2) obtuse protrusion ≤3 mm (III-OP), 3) obtuse protrusion ≥4 mm (IV-OP), and 4) acute protrusion of any size (IV-AP). The purposes of this study were to determine the prevalence of malignancy and histopathological features of class III and IV masses and subclasses. In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study, 3 fellowship-trained abdominal radiologists (R1-3) reviewed cystic renal masses that had tissue pathology and preoperative renal mass protocol computerized tomography or magnetic resonance imaging. Classes based on v2019 and prior classification systems were retrospectively re-assigned and associated with malignancy, aggressive histologic features (necrosis or high Fuhrman grade) and radiological progression following resection. The final sample included 79 masses (59 malignant, 20 benign) from 74 patients. Based on v2019, prevalence of malignancy ranged from 56% to 61% (mean 60%) for class III and 83% to 83% (mean 83%) for class IV (p=0.036, 0.013, 0.036 for 3 fellowship-trained abdominal radiologists). Prevalence of malignancy within subclasses were: III-WS (overall 49%; range 47%-53%); III-OP (76%; 71%-85%); IV-OP (78%; 75%-87%); IV-AP (87%; 82%-95%; p=0.029, 0.001, 0.005). All readers were more likely to classify malignancies with aggressive histologic features as class IV (88% to 100%) rather than class III (0% to 12%; p=0.012, <0.001, 0.002), corresponding to a negative predictive value of 96% to 100%. After treatment (mean followup length 1,210 days), 1 patient developed metastases. Bosniak Classification, version 2019 can help risk stratification of class III-IV masses by identifying those likely to be malignant and have aggressive histologic features.

Meta-MUMS DTA: Implementation, validation, and application of diagnostic test accuracy software for meta-analysis in radiology

PurposeGenerally, guiding clinical practice concentrates on the statistical techniques implemented for performing the diagnostic meta-analysis and test accuracy studies in a specific field of research. This study aims to implement a comprehensive diagnostic meta-analysis tool, which is user-friendly, free, and simple, and can be useful for diagnostic and bivariate model analysis purposes. MethodsThe Meta-MUMS DTA tool for meta-analysis developed in Matlab R2013a for the Microsoft Windows operating systems (32-bit and 64-bit). Meta-DiSc, Open-MetaAnalyst, Stata (Deeks' test) were the tools used for comparison purposes. ResultsThe features include determination of heterogeneity and computations of chi-square (Q, df, and p-value), I2, Γ2, and Spearman correlation tests, subgroup analysis, meta-regression techniques to explore the relationships of study characteristics and accuracy estimates and performing statistical pooling of sensitivities, specificities, likelihood ratio, and diagnostic odds ratios on fixed- and random-effects models as well as providing figures for forest plots with high quality. The Egger's regression test (along with its smooth version SVE and SVT), Deeks' regression test with funnel plots, and trim and fill were the tools for detecting publication bias. Bivariate model analysis of sensitivity and specificity accuracy is also available in this software. Publication bias and bivariate model analysis are super-advantageous of the proposed software. Moreover, a worked example to evaluate the diagnostic accuracy of mammography and magnetic resonance imaging in breast cancer is proposed. ConclusionThe Meta-MUMS DTA tool shows its advantages for upcoming diagnostic meta-analysis studies, especially in radiology science and hopefully may become a platform for teaching purposes.

Advancement of microdosimetric kinetic model in heavy-ion radiotherapy

To date, more than 11,000 cancer patients have been treated with therapeutic carbon-ion beams at the National Institute of Radiological Sciences (NIRS). In the treatment planning system, the biological effectiveness of the therapeutic carbon-ion beams has been predicted based on the microdosimetric kinetic (MK) model. The MK model has a variety of applications. For instance, it can be used to predict the biological effectiveness of therapeutic carbon-ion beams under protracted irradiations as well as under hypoxic conditions. Recently, we have updated the MK model to a stochastic microdosimetric kinetic (SMK) model for a new research project about hypo-fractionated multi-ion radiotherapy, referred to as a “Quantum Scalpel”. This report overviews advancement of the MK model in heavy-ion radiotherapy.

Microdosimetric study for helium-ion beam using fully 3D silicon microdosimeters

In this study, the survival fraction of pancreatic cancer cells exposed to a spread-out Bragg peak (SOBP) helium-ion beam are estimated using the microdosimetric method with the microdosimetric kinetic (MK) model, by measuring the specific energy with a microdosimeter. To measure the microdosimetric spectra, a 3D mushroom microdosimeter was used by mounting it on silicon-on-insulator (SOI) substrates. At different positions of the Bragg curve of a pristine helium-ion beam of 166 MeV/u, microdosimetric spectra were measured via a scanning beam port in the National Institute of Radiological Sciences. The MK parameters were determined such that the survival fraction (SF) calculated by the MK model predicts the previously reported in vitro data. For a cuboid target of 10×10×6 cm3, a treatment plan that utilised helium-ion beam was designed from the in-house treatment planning software (TPS) to achieve a 10% SF of pancreatic cancer cells throughout the target. The physical doses and microdosimetric spectra were measured for different depths by irradiating the scanning-SOBP helium-ion beam; consequently, the SF at each position of the SOBP was predicted. The predicted SFs from measured physical dose and microdosimetric spectra were in good agreement with the planned SF from TPS.

Estimation of Dose-Rate Effectiveness Factor for Malignant Tumor Mortality: Joint Analysis of Mouse Data Exposed to Chronic and Acute Radiation

Uncertainties due to confounding factors in epidemiological studies have limited our knowledge of the effects of low-dose-rate chronic exposure on human health. Animal experiments, wherein each subject is considered to be nearly identical, can complement the limitations of epidemiological studies. Therefore, we conducted a joint analysis of previously published cancer mortality data in B6C3F1 female mice chronically and acutely irradiated with 137Cs γ rays to estimate the dose-rate effectiveness factor. In the chronically irradiated animal experiment conducted by the Institute for Environmental Sciences, mice received irradiation at dose rates of 0.05, 1.1 or 21 mGy per day for 400 days from 8 weeks of age. For the acutely irradiated animal experiment conducted by the National Institute of Radiological Sciences, mice received irradiation at 35, 105, 240 or 365 days of age with 1.9, 3.8 or 5.9 Gy at a dose rate of 0.98 Gy per min. Because the preliminary analyses suggested that the risk was dependent on the age at exposure, a model was applied that considered risk differences depending on this factor. The model analysis revealed a three-fold, significantly decreased risk per Gy in mice exposed to 21 mGy per day compared to that in acutely irradiated mice. This resulted in a dose-rate effectiveness factor larger than that reported previously.

Electron beam scattering device for FLASH preclinical studies with 6-MeV LINAC

In this study, an electron-scattering device was fabricated to practically use the ultra-high dose rate electron beams for the FLASH preclinical research in Dongnam Institute of Radiological and Medical Sciences. The Dongnam Institute of Radiological and Medical Sciences has been involved in the investigation of linear accelerators for preclinical research and has recently implemented FLASH electron beams. To determine the geometry of the scattering device for the FLASH preclinical research with a 6-MeV linear accelerator, the Monte Carlo N-particle transport code was exploited. By employing the fabricated scattering device, the off-axis and depth dose distributions were measured with radiochromic films. The generated mean energy of electron beams via the scattering device was 4.3 MeV, and the symmetry and flatness of the off-axis dose distribution were 0.11% and 2.33%, respectively. Finally, the doses per pulse were obtained as a function of the source to surface distance (SSD); the measured dose per pulse varied from 4.0 to 0.2 Gy/pulse at an SSD range of 20–90 cm. At an SSD of 30 cm with a 100-Hz repetition rate, the dose rate was 180 Gy/s, which is sufficient for the preclinical FLASH studies.

Production cross-sections of Mo-isotopes induced by fast neutrons based on the 9Be(p, n) reaction

We measured the flux-weighted average cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions with the average neutron energies between 14.0- and 31.8-MeV by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were generated based on the 9Be(p, n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux was measured by using the 27Al(n, α)24Na monitor reaction, whereas the neutron spectra were simulated by using the MCNPX 2.6.0 code. The theoretical cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, xn)91.90,89Mo reactions as a function of mono-energetic neutron were calculated by using the TALYS-1.9 code. The present results for the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions are compared with the calculated neutron flux-weighted average values based on the literature data and theoretical cross-sections as a function of mono-energetic neutron energy, and show a good agreement.

Implementation of ultra-high dose-rate electron beam from 6-MeV C-band linear accelerator for preclinical study

Recent biological studies with ultra-high dose-rate (> 40 Gy/s) irradiation demonstrate the killing of tumors along with a reduction in the side-effect on normal tissues. These features can suggest the alternative radiotherapy method. The radio-biological mechanisms need to be understood, and to be applied tumor treatment. Biological validations of the ultra-high dose-rate beam are required. The 6-MeV electron linear accelerator constructed in 2015 at the Dongnam Institute of Radiological & Medical Sciences was upgraded to generate an electron beam at an ultra-high dose rate and to provide preclinical irradiation for in vitro studies of cells and small animals. The irradiation device was designed with a dual scattering foil system to achieve a uniform beam distribution with a diameter of 30 mm at a distance of 110 mm from the primary foil. The 6-MeV accelerator operating with a 6-MW pulse modulator based on a thyratron-switched pulse-forming network provides beam operation per pulse utilizing a single-board computer to control the pulse timing. The film dosimetry at a depth of 10 mm in a water phantom of the irradiation device demonstrated that a beam with an RF power of 2.5 MW and an electron-gun heating current of 2 A produced a dose per pulse of 4.22±0.12 Gy/pulse. This resulted in a dose rate of 422 Gy/s with a pulse rate of 100 Hz. The upgraded accelerator was successfully tested for preclinical use and is currently in full operation with studies being performed on the radio-biological effects of ultra-high dose-rate beam. The paper describes the design features of the ultra-high dose-rate electron beam generated from the 6-MeV accelerator and the dose measurement using the irradiation device. The design of the preclinical irradiator is also discussed.

Examination of the Practicability of Brain Atlas Technique in Patients with Intracranial Space-Occupying Lesions

Marianna Nagy*1, Csaba Aranyi2, Gábor Opposits2, Levente Lánczi1, Tamás Papp1, Mária Kern1, Tamás Spisák3, Ervin Berényi1 and Miklós Emri2 Author Affiliations 1Department of Medical Imaging, Division of Radiology and Imaging Science, Hungary 2Department of Medical Imaging, Division of Nuclear Medicine and Translational Imaging, Hungary 3Department of Neurology, Essen, Germany Received: August 13, 2020 | Published: August 21, 2020 Corresponding author: Marianna Nagy, Division of Radiology and Imaging Science, Department of Medical Imaging, Faculty of Medicine, 4032 Debrecen, Nagyerdei krt 98, Hungary DOI: 10.26717/BJSTR.2020.29.004842

A Regional Campus Approach to Culinary Medicine for Interprofessional Students

Purpose&#x0D; The purpose of this report is to describe and discuss an innovative culinary medicine interprofessional student educational project through collaboration with community partners. &#x0D; &#x0D; Method&#x0D; After adapting the culinary medicine program to meet interprofessional education requirements, students from interprofessional graduate healthcare programs on a regional medical campus participated in a culinary medicine active learning experience utilizing the Goldring© curriculum. For this project, students completed assigned readings prior to the hands-on culinary experience which utilized a patient case scenario and an educational debrief. Anonymous post-survey quantitative and qualitative data was collected to determine the students’ opinions of the learning experience and the application of the information learned for patient care.&#x0D; &#x0D; Results&#x0D; Thirty-three students from medicine, pharmacy, physical therapy, nursing, radiologic imaging science, and genetic counseling participated. The project consisted of three separate events, entailing the same learning experience. The students reported the learning experience to be highly valuable. Qualitative data analysis revealed three general themes: 1) the novelty of the information learned, 2) the relevance of the information for patients from the perspective of all disciplines represented in the learning experience, and 3) the value of teamwork. &#x0D; &#x0D; Conclusions&#x0D; Collaboration with a local community culinary arts school provided a unique and innovative learning opportunity for regional campus healthcare students. The focus of the culinary medicine learning experience to include interprofessional students created a rich learning environment allowing students to learn from, with, and about other healthcare disciplines in addition to practical application of culinary medicine. The culinary medicine program’s combination of didactic and culinary skills training was well received by students. Students had a positive response to the curriculum and experience stating that they learned information that they were excited to implement with their patients. To our knowledge UAMS Northwest Regional Campus is the first to implement culinary medicine curriculum with IPE requirements, and it is the first regional medical campus to implement the Goldring© curriculum.

Coronavirus 2019 Disease (COVID-19), Systemic Inflammation, and Cardiovascular Disease.

Acute respiratory failure associated with the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread worldwide and presents critical challenges for the public health and medical communities The World Health Organization (WHO) has declared SARS-CoV-2 a public health emergency of international concern, with a global estimate of over 7 million human infections and more than 400000 deaths worldwide as of June 12, 2020 A 2020 report by the China Medical Treatment Expert Group for Coronavirus disease 2010 (COVID-19) (2) showed that the clinical spectrum of the viral infection is dominated by fever (up to 88 7% of patients during hospitalization) and cough (67 8% of patients) followed by symptoms such as headache, fatigue, or shortness of breath

Stabilization of Plutonium(V) Within a Crown Ether Inclusion Complex

Crystalline coordination complexes of actinides, especially in atypical oxidation states, are not only fundamentally important for expanding the notably limited knowledge on the bonding nature of a...

Cytoplasmic Radiation Induced Radio-Adaptive Response in Human Lung Fibroblast WI-38 Cells.

It has been reported that in cells exposed to low-dose radiation, radio-adaptive responses can be induced which make irradiated cells refractory to subsequent high-dose irradiation. However, whether adaptive responses are possible when only the cytoplasm, not the nucleus, of the cell is exposed to radiation is still unclear. In this study, using the proton microbeam facility at the National Institute of Radiological Sciences (Japan), we found that cytoplasmic irradiation activates radio-adaptive responses in normal human lung fibroblast WI-38 cells. Our results showed that when cells received cytoplasmic irradiation with 500 protons prior to 2 Gy or 6 Gy X-ray broad-beam irradiation, the DNA double-strand break levels were significantly reduced. In contrast, at cytoplasmic irradiation with less than 100 protons, the radio-adaptive response was not detected. Moreover, the time interval between cytoplasmic irradiation and whole-cell X-ray irradiation should be longer than 6 h for the induction of adaptive responses. In addition, cytoplasmic irradiation elevated the level of cellular mitochondrial superoxide, which enhanced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK 1/2) and its mediated nuclear accumulation of nuclear factor (erythroid-derived 2)-like 2 (NRF2). This signaling pathway contributed to cytoplasmic irradiation-induced adaptive response as supported by the observations that treatment with the mitochondrial superoxide scavenger mito-tempol, ERK 1/2 inhibitor U0126 or NRF2 inhibitor ML385 could repress the adaptive response. Overall, we showed that cytoplasmic irradiation induces radio-adaptive responses and that mitochondrial superoxide/ERK 1/2/NRF2 signaling is a mechanism. Our results provide new information on the biological effects induced by cytoplasm-targeted irradiation.

Experimental study of an initially pressurized water target irradiated by a proton beam

This experimental visualization study was conducted to investigate and define the phenomena of an initially pressurized liquid water target that can prevent the boiling of water when the target is irradiated with a 30-MeV proton beam produced using the MC-50 Cyclotron at Korea Institute of Radiological and Medical Sciences. At various initial pressures and proton beam currents, the behavior of the target water was investigated using a complementary metal–oxide–semiconductor camera. We confirmed that an appropriate initial pressure could indeed prevent local bulk boiling, and be determined by solving Rayleigh's equation and the Clausius–Clapeyron equation for homogeneous bubble growth using the measured bubble size generated at the Bragg-peak region. The saturation temperature of the initial pressure must be higher than the calculated local water temperature at the Bragg-peak region. The final pressure of the water target increased proportionally with the initial pressure and proton beam current. The penetration depth of the beam varied with beam current and slightly with the final pressure, as evidenced by the emission of blue light in all experimental cases.

Quantitative Structure-Activity Relationship Models for Predicting Inflammatory Potential of Metal Oxide Nanoparticles.

Background:Although substantial concerns about the inflammatory effects of engineered nanomaterial (ENM) have been raised, experimentally assessing toxicity of various ENMs is challenging and time-consuming. Alternatively, quantitative structure–activity relationship (QSAR) models have been employed to assess nanosafety. However, no previous attempt has been made to predict the inflammatory potential of ENMs.Objectives:By employing metal oxide nanoparticles (MeONPs) as a model ENM, we aimed to develop QSAR models for prediction of the inflammatory potential by their physicochemical properties.Methods:We built a comprehensive data set of 30 MeONPs to screen a proinflammatory cytokine interleukin (IL)-1 beta () release in THP-1 cell line. The in vitro hazard ranking was validated in mouse lungs by oropharyngeal instillation of six randomly selected MeONPs. We established QSAR models for prediction of MeONP-induced inflammatory potential via machine learning. The models were further validated against seven new MeONPs. Density functional theory (DFT) computations were exploited to decipher the key mechanisms driving inflammatory responses of MeONPs.Results:Seventeen out of 30 MeONPs induced excess production in THP-1 cells. In vivo disease outcomes were highly relevant to the in vitro data. QSAR models were developed for inflammatory potential, with predictive accuracy (ACC) exceeding 90%. The models were further validated experimentally against seven independent MeONPs (). DFT computations and experimental results further revealed the underlying mechanisms: MeONPs with metal electronegativity lower than 1.55 and positive were more likely to cause lysosomal damage and inflammation.Conclusions: released in THP-1 cells can be an index to rank the inflammatory potential of MeONPs. QSAR models based on were able to predict the inflammatory potential of MeONPs. Our approach overcame the challenge of time- and labor-consuming biological experiments and allowed for computational assessment of MeONP inflammatory potential by characterization of their physicochemical properties. https://doi.org/10.1289/EHP6508

Polyethylene moderator optimized for increasing thermal neutron flux in the NASBEE accelerator-based neutron field

Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) at National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology (NIRS-QST) achieved thermal neutron flux of a therapeutic intensity of (1.75 ± 0.13) × 109 cm−2 s−1 by optimizing polyethylene (PE) moderator in the beam port. The dose contamination of gamma rays was 2.37 × 10−12 Gy cm2 (the absorbed dose of 14.9 Gy h−1). The improved thermal neutron field at the NASBEE facility will be useful in the research and development for boron neutron capture therapy (BNCT).

High-resolution angle-resolved photoemission study of oxygen adsorbed Fe/MgO(001)**Present address: Synchrotron Radiation Research Center, National Institutes for Quantum and Radiological Science and Technology, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan

We have investigated the electronic states of clean Fe(001) and oxygen adsorbed Fe(001)–p(1 × 1)-O films epitaxially grown on MgO(001) substrates by means of polarization-dependent angle-resolved photoemission spectroscopy (ARPES) and extensive density-functional theory (DFT) calculations. The observed Fermi surfaces and band dispersions of pure Fe near the Fermi level were modified upon oxygen adsorption. By the detailed comparison of ARPES and DFT results of the oxygen adsorbed Fe surface, we have clarified the orbital-dependent p–d hybridization in the topmost and second Fe layers. Furthermore, the observed energy levels and Fermi wave numbers for the oxygen adsorbed Fe surface were deviated from the DFT calculations depending on the orbital characters and momentum directions, indicating an anisotropic interplay of the electron correlation and p–d hybridization effects in the surface region.