X-ray Beam Research Articles

Development and validation of 3D printed anthropomorphic head phantom with eccentric holes for medical LINAC quality assurance testing in stereotactic radiosurgery

Stereotactic Radiosurgery (SRS) for brain tumors using Medical Linear Accelerator (LINAC) demands high precision and accuracy. A specific Quality Assurance (QA) is essential for every patient undergoing SRS to protect nearby non-cancerous cells by ensuring that the X-ray beams are targeted according to tumor position. In this work, a water-filled generic anthropomorphic head phantom consisting of two removable parts with eccentric holes was developed using Additive Manufacturing (AM) process for performing QA in SRS. In the patient specific QA, the planned radiation dose using Treatment Planning System (TPS) was compared with the dose measured in the phantom. Also, the energy consistency of radiation beams was tested at 200 MU for different energy beams at the central and eccentric holes of the phantom using an ionization chamber. Experimentally examined results show that planned doses in TPS are reaching the target within a 5% deviation. The ratio of the dose delivered in the eccentric hole to the dose delivered to the central hole shows variations of less than 2% for the energy consistency test. The designed, low-cost water-filled anthropomorphic phantom is observed to improve positioning verification and accurate dosimetry of patient-specific QA in SRS treatment.

Deciphering the Radiation Dose Summary Page in Interventional Fluoroscopy.

Fluoroscopy is an advanced medical imaging modality that utilizes x-rays to acquire real-time images throughout a medical examination. It is commonly used in various procedures such as in interventional radiology, cardiac catheterization, and gastrointestinal and genitourinary studies. While fluoroscopy is a valuable diagnostic and therapeutic tool, it exposes patients and medical staff to ionizing radiation, which carries health risks. A radiation dose summary page is a report generated by the fluoroscope that displays important information about the procedure. It provides an overview of the radiation doses administered during a fluoroscopic procedure, as well as certain technical parameters used during the irradiation events. The contents of a radiation dose summary page may vary depending on the make and model of the fluoroscope but some common elements include the cumulative reference air kerma, which serves as a surrogate of radiation dose delivered to the patient, and the dose-area product, which takes account of the x-ray beam area and is a measure of the total amount of energy imparted on the patient. Other imaging acquisition parameters may be also included in the dose summary page, including tube voltage, tube current, pulse width, pulse rate, spectral filters, primary and secondary angles, and source-to-image distance. The radiation dose summary page for fluoroscopy is a useful tool for physicians, technologists, and medical physicists, allowing them to comprehend the technical details of a fluoroscopically guided procedure. ©RSNA, 2024.

Characterization of Si particles in additively manufactured AlSi10Mg using synchrotron transmission X-ray nanotomography

Abstract In AlSi10Mg samples manufactured by Laser Powder Bed Fusion, distinguishing the Si eutectic network/Si particles from the Al matrix by X-ray imaging is challenging due to the low absorption contrast between the Al and Si. This work investigates the possibility of overcoming this obstacle in synchrotron transmission X-ray microscopy. Effects of both different defocusing conditions and X-ray beam energies are evaluated and optimal conditions are identified for imaging a sample annealed post-print for 2h at 520°C. It is shown that both large particles (e.g. 4μm) and particles as small as 0.5 μm, can be imaged with reasonable precision in 3D non-destructively.

Correcting directional dark field x-ray imaging artefacts using position dependent image deblurring and attenuation removal

In recent years, a novel x-ray imaging modality has emerged that reveals unresolved sample microstructure via a “dark-field image”, which provides complementary information to conventional “bright-field” images, such as attenuation and phase-contrast modalities. This x-ray dark-field signal is produced by unresolved microstructures scattering the x-ray beam resulting in localised image blur. Dark-field retrieval techniques extract this blur to reconstruct a dark-field image. Unfortunately, the presence of non-dark-field blur such as source-size blur or the detector point-spread-function can affect the dark-field retrieval as they also blur the experimental image. In addition, dark-field images can be degraded by the artefacts induced by large intensity gradients from attenuation and propagation-based phase contrast, particularly around sample edges. By measuring any non-dark-field blurring across the image plane and removing it from experimental images, as well as removing attenuation and propagation-based phase contrast, we show that a directional dark-field image can be retrieved with fewer artefacts and more consistent quantitative measures. We present the details of these corrections and provide “before and after” directional dark-field images of samples imaged at a synchrotron source. This paper utilises single-grid directional dark-field imaging, but these corrections have the potential to be broadly applied to other x-ray imaging techniques.

Performance characterization of an Al2O3/HfO2 parabolic multilayer based on a laboratory X-ray source

Parabolic multilayers (PMs) are widely used in synchrotron radiation, X-ray free electron lasers, laboratory X-ray sources, and so on, and therefore, how to expediently and effectively determine their performance is important for the designers, manufacturers, and users of them. This paper designed a method based on a laboratory X-ray source and polycapillary parallel X-ray lens to characterize the performances of one Al2O3/HfO2 PM. The results showed that a monochromatic X-ray beam with a width of 97.76 µm and a divergence of 0.667 mrad at Cu-K α (8.04 keV) was obtained with the PMs used in the paper based on a laboratory X-ray source with a focus size of 50–100 µm at various working powers, and its X-ray reflectivity for Cu-K α and Cu-K β was 43.71% and 38.62%, respectively.

Diamond sensors for hard X-ray energy and position resolving measurements at the European XFEL.

The diagnostics of X-ray beam properties has a critical importance at the European X-ray Free-Electron Laser facility. Besides existing diagnostic components, utilization of a diamond sensor was proposed to achieve radiation-hard, non-invasive beam position and pulse energy measurements for hard X-rays. In particular, with very hard X-rays, diamond-based sensors become a useful complement to gas-based devices which lose sensitivity due to significantly reduced gas cross-sections. The measurements presented in this work were performed with diamond sensors consisting of an electronic-grade single-crystal chemical-vapor-deposition diamond with position-sensitive resistive electrodes in a duo-lateral configuration. The results show that the diamond sensor delivers pulse-resolved X-ray beam position data at 2.25 MHz with an uncertainty of less than 1% of the beam size. To our knowledge this is the first demonstration of pulse-resolved position measurements at the MHz rate using a transmissive diamond sensor at a free-electron laser facility. It can therefore be a valuable tool for X-ray free-electron lasers, especially for high-repetition-rate machines, enabling applications such as beam-based alignment and intra-pulse-train position feedback.

Dosimetry of microbeam radiotherapy by flexible hydrogenated amorphous silicon detectors

Objective. Detectors that can provide accurate dosimetry for microbeam radiation therapy (MRT) must possess intrinsic radiation hardness, a high dynamic range, and a micron-scale spatial resolution. In this work we characterize hydrogenated amorphous silicon detectors for MRT dosimetry, presenting a novel combination of flexible, ultra-thin and radiation-hard features. Approach. Two detectors are explored: an n-type/intrinsic/p-type planar diode (NIP) and an NIP with an additional charge selective layer (NIP + CSC). Results. The sensitivity of the NIP + CSC detector was greater than the NIP detector for all measurement conditions. At 1 V and 0 kGy under the 3T Cu–Cu synchrotron broadbeam, the NIP + CSC detector sensitivity of (7.76 ± 0.01) pC cGy−1 outperformed the NIP detector sensitivity of (3.55 ± 0.23) pC cGy−1 by 219%. The energy dependence of both detectors matches closely to the attenuation coefficient ratio of silicon against water. Radiation damage measurements of both detectors out to 40 kGy revealed a higher radiation tolerance in the NIP detector compared to the NIP + CSC (17.2% and 33.5% degradations, respectively). Percentage depth dose profiles matched the PTW microDiamond detector’s performance to within ±6% for all beam filtrations except in 3T Al–Al due to energy dependence. The 3T Cu–Cu microbeam field profile was reconstructed and returned microbeam width and peak-to-peak values of (51 ± 1) μm and (405 ± 5) μm, respectively. The peak-to-valley dose ratio was measured as a function of depth and agrees within error to the values obtained with the PTW microDiamond. X-ray beam induced charge mapping of the detector revealed minimal dose perturbations from extra-cameral materials. Significance. The detectors are comparable to commercially available dosimeters for quality assurance in MRT. With added benefits of being micron-sized and possessing a flexible water-equivalent substrate, these detectors are attractive candidates for quality assurance, in-vivo dosimetry and in-line beam monitoring for MRT and FLASH therapy.

Evaluation of the measurement accuracy and uncertainty of a solid-state detector under diagnostic x-ray beam conditions.

An accurate measurement of x-ray beams is expected to reduce the uncertainties associated with estimating radiation risk to patients in clinical settings. To perform assessment tasks based on the readings of a solid-state detector (SSD) using semiconductor technology, the characteristics of the detector should be elucidated. In this study, we evaluated the measurement accuracy of a new SSD under diagnostic x-ray beam conditions in terms of air kerma, tube voltage, and half-value layer (HVL). The performance of the SSD was then compared with those of reference instruments. The tube voltage was varied within the range of 50-120kV in steps of 10kV and the thickness and materials of additional filters were concurrently changed (several combinations were tested). In addition, the dose rate and energy dependence of the SSD were also investigated. These effects were analyzed based on statistical significance tests. Furthermore, the expanded uncertainties in the series of measurements were meticulously calculated. The results showed average relative differences of -3.26±1.33%, 0.44±1.01%, and -2.60±3.31% for air kerma, tube voltage, and HVL, respectively. Furthermore, air kerma did not exhibit any dependence on dose rate and energy, in contrast to tube voltage and HVL measurements. The measurement values of the SSD fall within the acceptable range of uncertainty, highlighting its measurement accuracy and reliability. Furthermore, based on the characteristics elucidated by this study, valuable insights are provided concerning the assurance of appropriate measurement values in clinical settings.

Simultaneous imaging and element differentiation by energy-resolved x-ray absorption ghost imaging.

Based on the x-ray absorption edges of different elements, we simultaneously image and distinguish the composition of three differently shaped components of an object by using energy-resolved x-ray absorption ghost imaging (GI). The initial x-ray beam is spatially modulated by a series of Hadamard matrix masks, and the object is composed of three pieces of Mo, Ag, and Sn foil in the shape of a triangle, square, and circle, respectively. The transmitted x-ray intensity is measured by an energy-resolved single-pixel detector with a spectral resolution better than 0.8 keV. Through correlation of the transmission spectra with the corresponding Hadamard patterns, the spectral image of the sample is reconstructed, with a spatial resolution of 108 µm. Our experiment demonstrates a practical application of spectral ghost imaging, which has important potential for the noninvasive analysis of material composition and distribution in biology, medical science, and many other fields.

BEATS: BEAmline for synchrotron X-ray microTomography at SESAME.

The ID10 beamline of the SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) synchrotron light source in Jordan was inaugurated in June 2023 and is now open to scientific users. The beamline, which was designed and installed within the European Horizon 2020 project BEAmline for Tomography at SESAME (BEATS), provides full-field X-ray radiography and microtomography imaging with monochromatic or polychromatic X-rays up to photon energies of 100 keV. The photon source generated by a 2.9 T wavelength shifter with variable gap, and a double-multilayer monochromator system allow versatile application for experiments requiring either an X-ray beam with high intensity and flux, and/or a partially spatial coherent beam for phase-contrast applications. Sample manipulation and X-ray detection systems are designed to allow scanning samples with different size, weight and material, providing image voxel sizes from 13 µm down to 0.33 µm. A state-of-the-art computing infrastructure for data collection, three-dimensional (3D) image reconstruction and data analysis allows the visualization and exploration of results online within a few seconds from the completion of a scan. Insights from 3D X-ray imaging are key to the investigation of specimens from archaeology and cultural heritage, biology and health sciences, materials science and engineering, earth, environmental sciences and more. Microtomography scans and preliminary results obtained at the beamline demonstrate that the new beamline ID10-BEATS expands significantly the range of scientific applications that can be targeted at SESAME.

High-angular-sensitivity X-ray phase-contrast microtomography of soft tissue through a two-directional beam-tracking synchrotron set-up.

Two-directional beam-tracking (2DBT) is a method for phase-contrast imaging and tomography that uses an intensity modulator to structure the X-ray beam into an array of independent circular beamlets that are resolved by a high-resolution detector. It features isotropic spatial resolution, provides two-dimensional phase sensitivity, and enables the three-dimensional reconstructions of the refractive index decrement, δ, and the attenuation coefficient, μ. In this work, the angular sensitivity and the spatial resolution of 2DBT images in a synchrotron-based implementation is reported. In its best configuration, angular sensitivities of ∼20 nrad and spatial resolution of at least 6.25 µm in phase-contrast images were obtained. Exemplar application to the three-dimensional imaging of soft tissue samples, including a mouse liver and a decellularized porcine dermis, is also demonstrated.

Practices and Rules of 16th Century Genoese Gilding: Exploring Gold Leaf Thickness and Caratage through X-ray and Ion Beam Techniques

This study investigates the practices and rules of Genoese gilding, drawing insights from a 16th-century manuscript containing regulations for gold leaf production. Employing X-ray and ion beam techniques, we quantitatively assess the manuscript’s gold leaf thickness without destructive sampling. Artisanal goldbeater-produced leaves of different thicknesses, applied with a guazzo or mordant technique, served as standards. Further analysis of samples with unknown thickness from the furniture of Palazzo Spinola di Pellicceria in Genoa (Italy) has confirmed the method’s applicability to practical cases. External beam Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission (PIXE) analyses were carried out using 3 MeV protons at the LABEC accelerator laboratory in Florence. A linear relationship between Gold Lα peak yield and leaf thickness, as measured by RBS, has been established for optimal calibration of portable or hand-held X-Ray fluorescence (XRF) instrumentation for in situ measurements. Moreover, the caratage of the gold foil preserved in the manuscript has been assessed.

DISEASES THAT ARE DIAGNOSED AND TREATED BY X-RAYS AND GAMMA RAYS

rays have long been one of the most effective tools in detecting and diagnosing diseases because of their effective and practical properties in diagnosing the various diseases that appear in the x-ray image. Diagnostic x- rays are considered an examination carried out using To see the internal anatomy of the body Accurately and pinpoint the tiny spots. The x-ray beam passes through the body, and is absorbed in different quantities, depending on the absorption capacity of the material. Dense materials such as bones and metal appear in white in the x-ray image, while air in the lungs appears in black, and muscles and fat appear in shades of grey. In some tests, we resort to introducing contrast dyes such as iodine or barium into the body to provide more details of the part to be imaged, such as imaging the bile ducts, spinal cord (myelography), urinary tract, and other parts that need the use of contrast dyes. in These methods enabled us to diagnose various diseases such as chest diseases and various cancers If a foreign body is detected or calcium calcifications are seen.

Enhanced Cytotoxicity against a Pancreatic Cancer Cell Line Combining Radiation and Gold Nanoparticles.

The present work consisted of an exploratory study aiming to evaluate in vitro the potential of AuNPs during Radiation Therapy (RT) in human pancreatic adenocarcinoma cells. AuNPs coated with hyaluronic and oleic acids (HAOA-AuNPs) or with bombesin peptides (BBN-AuNPs) were used. AuNPs were characterized by Atomic Force Microscopy (AFM) and Dynamic Light Scattering. BxPC-3 tumor cells were irradiated with a 6 MV X-rays beam, in the absence or presence of AuNPs. AFM showed that HAOA-AuNPs and BBN-AuNPs are spherical with a mean size of 83 ± 20 nm and 49 ± 12 nm, respectively. For RT alone, a reduction in cell viability of up to 33 ± 12% was obtained compared to the control (p ≤ 0.0001). HAOA-AuNPs alone at 200 and 400 μM showed a reduction in cell viability of 20 ± 4% and 35 ± 4%, respectively, while for BBN-AuNPs, at 50 and 200 μM, a reduction in cell viability of 25 ± 3% and 37 ± 3% was obtained, respectively, compared to the control (p < 0.0001). At 72 h post-irradiation, a decrease in cell viability of 26 ± 3% and 22 ± 2% between RT + HAOA-AuNPs at 400 μM and RT + BBN-AuNPs at 50 μM, compared to RT alone, was obtained (p < 0.004). The combination of RT with AuNPs led to a significant decrease in cell viability compared to the control, or RT alone, thus representing an improved effect.

In-situ mapping of monocrystalline regions on Mars

Elemental quantification instruments for planetary missions provide a capability for in-situ identification of mineral phases via stoichiometry, an essential step in petrological investigations. X-ray fluorescence (XRF) has been employed for this purpose by multiple generations of Mars rovers (i.e., Pathfinder, Spirit and Opportunity, Curiosity and Perseverance). The Planetary Instrument for X-ray Lithochemistry (PIXL) aboard Perseverance rasters a micro-focused X-ray beam to generate micron-mm-sized maps illustrating variations in elemental composition and allowing mission scientists to identify rock components (i.e., sedimentary grains, veins and igneous crystals). Energy-dispersive X-ray diffraction can also be detected with PIXL and can be used as an additional constraint on component boundaries, providing PIXL with the capability to map monocrystalline regions in-situ. Here we introduce and apply a new method where each diffraction peak is partitioned independently according to its energy, using the instrument geometry to inform consistent partitioning. Applying this method to datasets acquired from the Dourbes abrasion patch in the Séítah formation of Jezero crater, Mars, reveals monocrystalline regions that were hidden using previous methods. This application of the technique allows faster and more accurate visualization of petrographic textures in future PIXL datasets, in particular those with rock components that are not easily separable using stoichiometry alone.

Spatial Resolution for X-ray Excited Luminescence Chemical Imaging (XELCI).

Measuring chemical concentrations at the surface of implanted medical devices is important for elucidating the local biochemical environment, especially during implant infection. Although chemical indicator dyes enable chemical measurements in vitro, they are usually ineffective when measuring through tissue because the background obscures the dye signal and scattering dramatically reduces the spatial resolution. X-ray excited luminescent chemical imaging (XELCI) is a recent imaging modality which overcomes these limitations using a focused X-ray beam to excite a small spot of red light on scintillator-coated medical implants with well-defined location (because X-rays are minimally scattered) and low background. A spectrochemical indicator film placed over the scintillator layer, e.g., a polymer film containing pH-indicator dyes, absorbs some of the luminescence according to the local chemical environment, and this absorption is then detected by measuring the light intensity/spectrum passing through the tissue. A focused X-ray beam is used to scan point-by-point with a spatial resolution mainly limited by the X-ray beam width with minimum increase from X-ray absorption and scattering in the tissue. X-ray resolution, implant surface specificity, and chemical sensitivity are the three key features of XELCI. Here, we study spatial resolution using optically absorptive targets. For imaging a series of lines, the 20-80% knife-edge resolution was ∼285 (±15) μm with no tissue and 475 ± 18 and 520 ± 34 μm, respectively, through 5 and 10 mm thick tissue. Thus, doubling the tissue depth did not appreciably change the spatial resolution recorded through the tissue. This shows the promise of XELCI for submillimeter chemical imaging through tissue.

Pediatrics organ dose and lifetime attributable cancer risk estimates in routine computed tomography

ObjectivesEvaluating organ doses received by pediatric patients and estimating lifetime attributable risk (LAR) in Riyadh, Saudi Arabia from chest and abdominal pelvic Computed Tomography (CT) scans. MethodsA total of 155 patients under the age of 15 were divided into four age groups: under 1, 1–5, 5–10, and 10–15. The organ dose was determined using the National Cancer Institute dosimetry system for (NCICT) software, and the LAR if cancer incident was measured according to the BEIR VII report. The 1st, 2nd, and 3rd quartiles were calculated for organs received primary X-ray beams. ResultsThe highest and lowest median doses were for the kidney in the 10-15-year-old group 4.84 mGy (Cl95%, 0.15–9.54) and the prostate in the >1-year-old group 0.02 mGy (Cl95%, −0.01 – 0.05), respectively. Furthermore, there was a correlation between age and breast doses in chest scans, as median doses increased from 0.08 mGy to 3.70 mGy. Breast cancer in females had a highest LAR from chest CT and colon cancer in abdomen-pelvic CT. The group 1–5 years old had the highest risk of breast cancer, followed by chest CT (LAR = 25.94). However, colon cancer (LAR = 10.39), followed by an abdomen-pelvic CT, had the highest risk in the same group in both genders. Colon and breast cancers had the highest LAR among males and females in all groups. ConclusionThe study found that older patients received higher median organ doses for the same examination than younger patients. Females have greater organ doses in the thorax compared to males, resulting in a higher mean LAR. While CT scans are useful tools for diagnosis, it's essential to consider the patient's dose, particularly in pediatric cases.

Exploring single-shot propagation and speckle based phase recovery techniques for object thickness estimation by using a polychromatic X-ray laboratory source.

Propagation and speckle-based techniques allow reconstruction of the phase of an X-ray beam with a simple experimental setup. Furthermore, their implementation is feasible using low-coherence laboratory X-ray sources. We investigate different approaches to include X-ray polychromaticity for sample thickness recovery using such techniques. Single-shot Paganin (PT) and Arhatari (AT) propagation-based and speckle-based (ST) techniques are considered. The radiation beam polychromaticity is addressed using three different averaging approaches. The emission-detection process is considered for modulating the X-ray beam spectrum. Reconstructed thickness of three nylon-6 fibers with diameters in the millimeter-range, placed at various object-detector distances are analyzed. In addition, the thickness of an in-house made breast phantom is recovered by using multi-material Paganin's technique (MPT) and compared with micro-CT data. The best quantitative result is obtained for the PT and ST combined with sample thickness averaging (TA) approach that involves individual thickness recovery for each X-ray spectral component and the smallest considered object-detector distance. The error in the recovered fiber diameters for both techniques is , despite the higher noise level in ST images. All cases provide estimates of fiber diameter ratios with an error of 3% with respect to the nominal diameter ratios. The breast phantom thickness difference between MPT-TA and micro-CT is about 10%. We demonstrate the single-shot PT-TA and ST-TA techniques feasibility for thickness recovery of millimeter-sized samples using polychromatic microfocus X-ray sources. The application of MPT-TA for thicker and multi-material samples is promising.

How numerical simulations helped to achieve breakeven on the NIF

The inertial confinement fusion program relies upon detailed simulations with inertial confinement fusion (ICF) codes to design targets and to interpret the experimental results. These simulations treat as much physics from essential principles as is practical, including laser deposition, cross beam energy transfer, x-ray production and transport, nonlocal thermal equilibrium kinetics, thermal transport, hydrodynamic instabilities, thermonuclear burn, and transport of reaction products. Improvements in radiation hydrodynamic code capabilities and vast increases in computing power have enabled more realistic, accurate 3D simulations that treat all known asymmetry sources. We describe how numerical simulations helped to guide the program, assess the impediments to breakeven, and optimize every aspect of target design. A preshot simulation of the first National Ignition Facility experiment that surpassed breakeven predicted an increased yield that matches the experimental result, within the preshot predicted uncertainty, with a target gain of 1.5. We will cover the key developments in Lawrence Livermore National Laboratory ICF codes that enabled these simulations and give specific examples of how they helped to guide the program.

Characterization of X-ray Beam for Half and Quarter Value Layers

Introduction: The aim of this work is to assess the penetrating ability of an X-ray beam through a specific material, in conditions of narrow-beam geometry. Materials and Methods: During the experiment, samples were switched with the X-ray tube turned off, and the primary intensity of the unshielded X-ray beam (fixed 2.5mm shielding) was measured. Parameters were kept constant throughout, and the electrometer was used to stabilize the readings. Subsequent measurements aimed to determine the Half-Value Layer (HVL) and Quarter-Value Layer (QVL) by interpolating various sample slices to achieve intensity values of I/2 and I/4, respectively. The data were used to plot and analyze HVL and QVL graphs, providing insights into the attenuation properties of the X-ray beam through different materials. Findings of the result: The primary findings indicated that the initial unshielded X-ray beam intensity, with parameters set to 37.5 kV and 40 mA, provided a stable baseline measurement. The results showed a consistent decrease in intensity with increased sample thickness, confirming the exponential attenuation of X-rays. The HVL was determined by identifying the sample thickness that reduced the initial intensity by half, and the QVL by the thickness reducing it to one-fourth. The experimental data closely followed theoretical predictions, with HVL and QVL values providing a quantitative measure of the material's attenuation properties. Conclusion: Graphical analysis of the results demonstrated clear linear relationships on a semi-logarithmic scale, validating the accuracy of the measurement process and the reliability of the electrometer readings. These findings contribute to a better understanding of X-ray attenuation in different materials, which is crucial for various applications in medical physics and radiography.