X-ray Photon Beam Research Articles

Quantification of hardware effects of an on-line Dual Energy X-ray Absorptiometry scanner when predicting lamb carcass composition

An on-line Dual Energy X-ray Absorptiometry (DXA) scanner's tissue composition prediction precision and accuracy was tested across the entire height of the unit's detector, and the hardware was assessed for robustness by measuring X-ray photon intensity throughout production days. There was good precision when predicting the tissue composition of 5 different lamb fat and lean muscle mixtures across 3 different thicknesses (R2 = 0.93 to 0.98, RMSE = 3.18% to 5.83%), however was less precise at the greatest thickness of 200 mm (R2 = 0.59, RMSE = 11.4%). There was no significant difference in the prediction of tissue composition at 8 of the 9 detector positions, however the position at the perpendicular of the X-ray photon beam was significantly different, with a fat prediction error of −4%, although no lamb carcass is detected in this position during normal production. A significant upwards drift in X-ray photon intensity was found over the course of production, especially immediately after restarting the DXA scanner following a period of inactivity. This upwards drift may affect tissue composition predictions over the span of a production day if uncorrected.

Prediction on X-ray output of free electron laser based on artificial neural networks

Knowledge of x-ray free electron lasers’ (XFELs) pulse characteristics delivered to a sample is crucial for ensuring high-quality x-rays for scientific experiments. XFELs’ self-amplified spontaneous emission process causes spatial and spectral variations in x-ray pulses entering a sample, which leads to measurement uncertainties for experiments relying on multiple XFEL pulses. Accurate in-situ measurements of x-ray wavefront and energy spectrum incident upon a sample poses challenges. Here we address this by developing a virtual diagnostics framework using an artificial neural network (ANN) to predict x-ray photon beam properties from electron beam properties. We recorded XFEL electron parameters while adjusting the accelerator’s configurations and measured the resulting x-ray wavefront and energy spectrum shot-to-shot. Training the ANN with this data enables effective prediction of single-shot or average x-ray beam output based on XFEL undulator and electron parameters. This demonstrates the potential of utilizing ANNs for virtual diagnostics linking XFEL electron and photon beam properties.

Evaluation of a novel N-(Hydroxymethyl) acrylamide polymer gel dosimeter formulation with organic glucose additive for radiotherapy

In this study, the first evaluation of organic sensitizer material on N-(Hydroxymethyl) acrylamide (NHMA) polymer gel dosimeter was presented. A novel tissue-equivalent polymer gel formula composed of NHMA containing different concentrations of organic glucose additive (GL-NHMA) was developed and evaluated for its potential use to measure 3D dose distributions to compare with treatment planning system. The new polymers of GL-NHMA were irradiated using a linear accelerator (LINAC) with a megavolt X-ray photon beam over a dose range of 2–20 Gy, energies of 6, 10, and 15 MV, and dose rates of 50, 200, and 500 cGy/min. The samples were evaluated using 0.5 T nuclear magnetic resonance (NMR) technique in terms of spin-spin relaxation rate (R2). Comparing with the conventional NHMA composition (i.e., 0 wt% GL concentration), the sensitivity of the GL-NHAM was improved by 53%, 68%, 89%, and 115% with 10, 15, 20, and 25 wt% GL, respectively, with an excellent linear dose response up to 8 Gy. There were no observable effects on the R2 dose response induced by varying the dose rate, photon energy, and irradiation temperature. The polymerization was stable after irradiation for a period of 10 days. Additionally, the R2 values decreased with increasing the scanning temperature. The dosimeter is water equivalent and is energy-independent from 0.1 to 20 MeV when considering the optimum composition. The gel dosimetry accuracy was evaluated in this study by calculating the overall uncertainty and found to be 4.64% (2σ, 95% confidence level). The GL additive acts as an excellent organic sensitizer in the GL-NHMA system, suggesting that this improved polymer formulation may be a useful tool for measuring dose distributions in radiotherapy at clinically relevant dose levels.

Monte-Carlo simulation of charge sharing in 2 mm thick pixelated CdTe sensor

Precise physical models of sensors are essential for developing high precision pixelated detectors. Advanced technologies allowed pixel electronics to be integrated in tens of micrometers pixel pitch. Such fine pixelated detectors suffer from charge sharing effect and, in high-Z materials, also from fluorescent photons traversing one or more pixels. This work presents a Monte-Carlo model of a 2 mm thick 70 μm pitch pixelated CdTe sensor designed for simulation of the absorption of X-ray photons from monochromatic X-ray photon beams. Charge diffusion across a pixel matrix was computed using a drift-diffusion model for each photon generating free electron-hole pairs. Based on the simulation outcome, we estimated the dependence of cluster size on photon energy and total charge distribution between neighboring pixels.

STUDIES ON RADIATION SHIELDING PROPERTIES OF NEWLY DEVELOPED HIGH-DENSITY CONCRETE FOR ADVANCED RADIOTHERAPY FACILITIES.

The linear attenuation coefficients and tenth-value layers are determined experimentally for the newly developed Cement-based high-density Concrete and Fly-Ash-based Geopolymer high-density Concrete using Red-Mud-based synthetic aggregate made up from industrial waste. Linear attenuation coefficients were determined in narrow and broad beam conditions for five megavoltage X-ray photon beam energies, i.e. 6, 10, 15 MV, and 6 and 10 MV-FFF generated by Varian TrueBeam medical linear accelerator. These materials are found to be more effective in radiation shielding when compared with ordinary concrete and hematite ore-based high-density concrete making it a useful construction material for radiotherapy accelerator vaults. Similar values of linear attenuation coefficients are observed for all the above-mentioned X-ray beam energies when cement is replaced with fly-ash in ordinary concrete, hematite-based high-density concrete and red-mud-based high-density concrete, making it a good eco-friendly alternative of cement and useful for the construction of radiotherapy vaults.

Infrared nanospectroscopy characterization of metal oxide photoresists

Implementation of extreme ultraviolet (EUV) lithography in high-volume semiconductor manufacturing requires a reliable and scalable EUV resist platform. A mechanistic understanding of the pros and cons of different EUV resist materials is critically important. However, most material characterization methods with nanometer resolution use an x-ray photon or electron beam as the probe, which often cause damage to the photoresist film during measurement. Here, we illustrated the use of non-destructive infrared nanospectroscopy [or nano-Fourier-transform infrared spectroscopy (nano-FTIR)] to obtain spatially resolved composition information in patterned photoresist films. Clear evidence of exposure-induced chemical modification was observed at a spatial resolution down to 40 nm, well below the diffraction limit of infrared light. With improvements, such a nano-FTIR technique with nanoscale spatial resolution, chemical sensitivity, and minimal radiation damage can be a promising candidate for the fundamental study of material properties relevant to EUV lithography.

Optical, photoluminescence and thermoluminescence characterization of holmium doped hafnium oxide nanoparticles as radiation dosimeter

Intrinsic and Ho3+ doped HfO2 nanopowder are obtained by the co-precipitation route calcined at 800 °C for 2 h. While using powder X-ray diffraction (PXRD) measurements it has been observed that there is a structural transformation from monoclinic to cubic phase, which is stabilized in 10.0 mol% of Ho doped HfO2 NPs. The elements analysis and morphology of the synthesized NPs are examined by FESEM-EDX. The presence of the water-related bonds in the samples is confirmed by FTIR spectroscopy. Raman measurement shows that the crystalline phase of monoclinic to cubic phase transformation and the evidence to the XRD. Photoluminescence spectra of Holmium dopant showed the characteristics peak of strong two green emission bands. The photoluminescence result indicates that the maximum emission occurs at a concentration of 2.5 mol% for Ho3+, which correlates with TL response. The defects/trap state of Ho doped of HfO2 NPs was identified using TL glow curve by 15 MV X-ray photon beam and this trap information is referred to by its kinetic parameters such as its activation energy, frequency factor, and order of kinetics which is determined by Glow Fit software. Ho (2.5 mol%): HfO2 NPs shows the best possible concentration for emission higher Integral TL intensity and it can be used as radiation dosimeter.

X-ray beam monitoring and wavelength calibration using four-beam diffraction.

Rigorous dynamical theory calculations show that four-beam diffraction (4BD) can be activated only by a unique photon energy and a unique incidence direction. Thus, 4BD may be used to precisely calibrate X-ray photon energies and beam positions. Based on the principles that the forbidden-reflection 4BD pattern, which is typically an X-shaped cross, can be generated by instant imaging using the divergent beam from a point source without rocking the crystal, a detailed real-time high-resolution beam (and source) position monitoring scheme is illustrated for monitoring two-dimensional beam positions and directions of modern synchrotron light sources, X-ray free-electron lasers and nano-focused X-ray sources.

Dosimetric Verification of Gamma Passing Rate for Head and Neck Cases Treated with Intensity Modulated Radiation Therapy (IMRT) Treatment Planning Technique

Each Intensity Modulated Radiation Therapy (IMRT) plan needs to be tested and verified before any treatment to check its quality. Octavius 4D-1500 phantom detector is a modern and qualified device for quality assurance procedure. This study aims to compare the common dosimetric criteria 3%/3 mm with 2%/2 mm for H&N plans for the IMRT technique. Twenty-five patients with head and neck (H&N) tumor were with 6MV x-ray photon beam using Monaco 5.1 treatment planning software and exported to Elekta synergy linear accelerator then tested for pretreatment verification study using Octavius 4D-1500 phantom detector. The difference between planned and measured dose were assessed by using local and global gamma index (GI) analysis method at threshold 10%. The DD/DTA criteria are performed with 3%/3 mm and 2%/2 mm. A significant difference is shown between the measured and calculated point dose for the treatment plans. A comparison made between the gamma passing rate between the 2%/2 mm and 3%/3 mm shows a significant difference for local and global which shows that the 2%/2 mm are more sensitive to dose variation than 3%/3 mm. The total monitor unit (MU) shows a negative linear relationship with both criteria and %GP types. A significant correlation is shown between the total MU and global %GP at 2%/2 mm criterion. The conclusion of the study indicates that 2%/2 mm criterion is more sensitive to the dose distribution changes than the 3%/3 mm. The total number of monitor units should be taken into consideration during the planning of H&N tumors using the IMRT plans.

A comparative study of the dosimetric impact on IMRT planning with VMAT plans using a varying number of arcs in prostate cancer

A study has been carried out to explore the impact by varying the number of arcs and beam arrangement on dose distributions. For this volumetric modulated arc therapy and 7-field, intensity-modulated radiation therapy plans have use for prostate cancer cases. The eclipse treatment planning system version 13.6 (Varian California, USA) was used to assess dosimetry data for 20 patients. All patients received intensity-modulated radiation therapy and volumetric modulated arc therapy plans with a varying number of arcs. 6MV X-Ray photon beam energy uses for each patient. Statistical plan assessments have been carried out for various dosimetric parameters to evaluate execution efficiency. There were no statistically significant changes (p>0.05) observed in D98% dose coverage while D2%, conformity index, homogeneity index, monitor unit, and treatment delivery time were showing statistically significant changes (p<0.05). In contrast to six arc volumetric modulated arc therapy and 7 field-intensity-modulated radiation therapy plans, Single arc volumetric modulated arc therapy plans showed 23.28 % and 25.96 % less monitor unit, 97.52 % and 137.53 % less treatment delivery time. It concluded that using a higher number of arcs in volumetric modulated arc therapy plans for prostate cancer improves plan efficiency. The four arc volumetric modulated arc therapy plans appeared to provide a reasonable trade-off between enhanced treatment delivery time and high treatment plan quality.

X-Ray Crystalline Undulator Radiation in Water Window

The problem of radiation produced by the bunch of relativistic positrons, channeled into the crystalline undulator, is considered, taking into account the polarization of a crystal medium. If a bunch energy is above the threshold energy, then the radiation is generated in the limited frequency range, due to the medium polarization. Both soft and hard boundary photons are emitted at a zero angle. When the ratio of the bunch energy to the threshold energy approaches unity from above, the peak of the bunch radiation spectrum is near the resonant frequency and can fall into the soft X-ray frequency range due a certain choice of the parameters of the crystalline undulator. In that case, it is necessary to use a low energy relativistic bunch. Method is effective because a fairly dense beam of soft X-ray photons is generated. It is shown the possibility of obtaining monochromatic, intense, directed photon beams in the water window region, important for medical and biological applications.

Evaluation of scatter suppression algorithm for X-ray exposure of soft tissue equivalent phantoms over nominal energy range using FLUKA code

Soft tissue imaging is heavily impaired by streaks and cupping effects associated with X-ray scatter. Quality of images from projection imaging may be improved by the use of enhanced anti-scatter grids’ designs with potency to reject significant scatter. However, optimization of grid characteristics requires investigation to improve diagnostic image quality. Transmitted scatter spatially distributed degrades images engendering need for effective scatter correction protocols. This study investigated the pre-scan scatter suppression algorithm for X-ray exposure of soft tissue equivalent phantoms over nominal energy range. Adipose tissue and polymethyl methacrylate phantoms of cross-sectional area (30 x 30) cm2 and of varying thickness from 2 to 8 cm in 1 cm increments were successively exposed using energy ranging between 20–50 kVp. Monte Carlo simulation based on FLUKA code and flair interface was used to generate an input file for execution. The source simulated five cycles of ten million photons each of annular X-ray photon beam of radius, r = 0.5 cm at fixed field of view (FOV) through anti-scatter grid on to gadolinium oxysulfide detector. The transmitted total, scatter and primary estimates were evaluated with and without grids over varying phantom thicknesses, energy and grid design features. The simulated and experimental results obtained were comparable and in agreement with previous literature. Pearson’s correlation coefficients for scatter fraction and scatter to primary ratio were 0.983 and 0.981, respectively. The strong correlation between simulation and experiment results indicated correctness in methodology and protocol. The algorithms and protocols in the simulation would be appropriate for designing grids with enhanced scatter rejection capabilities.&#x0D; Keywords: FLUKA code, Monte Carlo simulation, Scatter suppression algorithm, Scatter correction, X-ray imaging systems.&#x0D;

Improved performance of N-(Hydroxymethyl)acrylamide gel dosimeter using potassium chloride for radiotherapy

In this study, polymer-gel dosimeters containing N-(Hydroxymethyl) acrylamide (NHMA) with different concentrations of potassium chloride (KCl) were developed and introduced for use in radiotherapy. The gels were irradiated with a megavolt X-ray photon beam up to 10 Gy using a medical linear accelerator. The irradiated NHMA_KCl dosimeters were evaluated by nuclear magnetic resonance (NMR), in terms of relaxation rate (R2). The results show that the dose sensitivity of polymer gel was improved by 33% when KCl concentration was increased from 0 to 1.9 wt%. The decrease in R2 values with increasing scanning temperature was 1.6% per °C at 6 Gy. The dosimeter was found stable within a period of 2–120 h after irradiation and is independent of dose-rate in the range of 50–600 cGy/min and independent of photon beam energy between 6 and 15 MV within 7.5% overall uncertainty.

Optimum Treatment Planning Technique Evaluation For Synchronous Bilateral Breast Cancer With Left Side Supraclavicular Lymph Nodes

Background: the Bilateral breast cancer cases are classified as a complex in radiotherapy treatment especially those with the left side mastectomy and right-side lumpectomy with left side supraclavicular lymph nodes patients. The purpose of this study is to find the optimum treatment planning technique among the three available techniques: 3D-CRT, IMRT, and VMAT.Materials and Methods: Ten Bilateral breast cancer included in this study with left side mastectomy and right-side lumpectomy with left side supraclavicular lymph nodes. The cross-sectional clinical study conducted in Baghdad ‎radiotherapy and nuclear medicine and Al-Andalus privet radiotherapy ‎hospital, Baghdad, Iraq. The patients are delineated by oncologists and prepare for radiation planning by MONACO 5.1 treatment planning system (TPS) with an X-ray photon beam of 6 MV or 10 MV energy using ‎ELEKTA‏’‏s Agility linear accelerator. The prescribed dose set at (4005 cCy per 15 fractions. Results: The treatment with 3D-CRT, IMRT, and VMAT show a significant difference in the results. VMAT give high dose distribution for the left mastectomy breast and it’s regional supraclavicular lymph nodes while the IMRT gives a higher value for the right side breast with lumpectomy. The good homogeneity index acquired with IMRT while VMAT gives a better conformity index. The 3D-CRT planning technique lowers the dose tho the heart and lunges better than the other techniques.Conclusion: Depending on the patient health and stage, the optimum treatment planning applied. Generally, VMAT is the optimum treatment planning technique for the studied group of SBBC patients. IMRT give effective coverage results better than the 3D-CRT.

Thermo-luminescence Response of Carbon Nanotubes and Some Other Familiar TL Materials Using Medical LINAC

Strain and impurity defects in carbon nanotubes (CNTs) particularly their potentiality as a new TL material has been studied over the years. In this research, our main objective is to explore the suitability of using CNTs and its composites in the area of TL dosimeter. For this purpose, a study was carried out between the TL responses of the dosimeters TLD-100, TLD-7000 and NaI-LiF pellets. To carry out this research, equivalent irradiations were performed with these pellets using clinical linear accelerator (LINAC) under 6 MV X-ray photon beam. The dose range was from 0.5 to 5 Gy. During irradiation, the dose rate was kept constant at 300 MU/min. TLD reader was used to readout the samples in a flowing N2 atmosphere to reduce surface oxidation.During readout, pre-heat temperature was set initially at 50 °C, acquired temperature rate 10 °C/s and maximum annealed temperature was 300 °C. Response of TLD-100 under varying dose was typically linear for any doses but other dosimeters TLD-7000 showed supra-linearity beyond 2 Gy and NaI-LiF pellets showed sub-linearity response after 2 Gy. The TL glow peak of CNTs indicated that it was lying somewhere away from 300 °C.

Verification Of Percentage Depth-Doses With Monte Carlo Simulation and Calculation Of Mass Attenuation Coefficients For Various Patient Tissues In Radiation Therapy

Objective: First part of this work dedicated to the verification of the percentage depth dose curves that obtained experimentally for 6 MV and 18 MV x-ray photon beams via using Geant4 Monte Carlo simulation. Second part of this study compared the computed mass attenuation coefficients of various human tissues and water between MATLAB and XCOM. Material-Methods: The central-axis percentage depth doses of Varian Clinac IX linear accelerator were verified via Monte Carlo simulation (Geant4) with square field sizes (10x10 and 30x30 cm2) for 6 MV and 18 MV x-ray photon energies. In addition, mass attenuation coefficients of adipose tissue, blood, muscle, bone, skin and water were computed with MATLAB and were compared with the NIST XCOM data. Results: Results of the Geant4 modeling were in line with the experimental measurements for percentage depth dose curves. The consistency of Geant4 with experimental results was more explicit for 6 MV photons with the field size of 10x10 cm2. No statistical significant difference between MATLAB and XCOM were found for all mentioned human tissues, except for bone (p=0.039 for bone in both genders). The minimum median percentage difference were calculated for water and skin with a result of 1.23% and 2.19%, respectively. Conclusion: Geant4 can be used to predict percentage depth dose curves for medical linacs. Mass attenuation coefficients calculated with MATLAB yielded consistent results with previous studies, which means MATLAB can be used as an alternative simulation tool for estimating mass attenuation coefficients of various human tissues and water.

Tomographic-based 3D scintillation dosimetry using a three-view plenoptic imaging system.

To demonstrate the feasibility of a three-plenoptic camera projection, scintillation-based dosimetry system for measuring three-dimensional (3D) dose distributions of static photon radiation fields. Static x-ray photon beams were delivered to a cubic plastic scintillator volume embedded within acrylic blocks. For each beam, three orthogonal projections of the scintillating light emission were recorded using a multifocus plenoptic camera. Experimental 3D reconstructions of the light distribution were obtained using an iterative maximum likelihood-expectation maximization (ML-EM) algorithm. For this purpose, the elements of the system matrix representing the contribution of the scintillator volume voxels to the camera sensor pixels were calculated using optical design software. A reconstruction-specific correction was applied to light reconstructions to account for scintillating light imaged by the camera but not directly resulting from dose deposition. Cross beam profiles (CBPs) and percentage depth dose (PDD) curves were compared to treatment planning system data for square fields. Three-dimensional and 3D gamma analyses were performed for concave-shaped dose distributions and the Pearson correlation coefficient and reconstruction error were employed to assess the quality of the measured relative 3D dose distributions. A full and accurate model of the plenoptic camera-based scintillation dosimetry system was implemented using the light ray tracing capabilities of optical design software. With this model, light distributions were successfully reconstructed over a volume of 60×60×60mm at a resolution of 2mm. For relative 3D measurements of square radiation fields of , and compared with treatment planning system reference distributions, the maximum root-mean-square error of the CBPs evaluated at two different depths was of 3.2%, 1.2%, and 1.1%, respectively; as for the corresponding linearly fitted PDDs of the square fields, the slopes of the reconstructed dose distributions overestimated those of the reference distributions by at most 0.2%/cm. The 2D gamma passing rate with a criterion of 2%/2mm for the concave-shaped photon field was of 61.6%, 66.1%, and 76.4% using one, two, and three plenoptic projections; the respective success rates become 77.1%, 87.5%, and 94.9% using a criterion of 3%/3mm. The 3D correlation coefficient for the corresponding reconstructions was of 0.688, 0.905, and 0.976, respectively. Three-dimensional light distributions emitted from within a plastic scintillator volume were successfully recovered using optical design software to establish a complete tomographic model of a plenoptic camera-based prototype. The tomographic model can equivalently extend to dynamic dose delivery measurements, providing temporal resolution limited by the camera's exposure time. This feasibility study enables a simplified design-to-implementation process for volumetric scintillation dosimetry prototypes toward fully meeting the clinical needs of 3D dose measurements for static and dynamic delivery techniques.

A New Superconducting Undulator Cryostat for the APS Upgrade

The Advanced Photon Source (APS) is in the midst of a major facility upgrade including both a new electron storage ring (SR) and many new insertion devices (IDs) providing x-ray photon beams to a new suite of experimental end stations. Included among the new IDs are four 4.8-meter superconducting undulator (SCU) cryostats, each containing two 1.8-meter planar undulator magnets operating at 4.2 K in either a phase shifted or canted configuration. We describe a new, compact cryocooler-based cryostat design which supports the magnets and associated subsystems and also fits the space constraints of the SR ID straight sections. The design is an evolution of earlier single-magnet 2-meter cryostats, retaining some subsystem commonality while incorporating lessons learned and several features unique to the challenge of supporting two independently operable undulator magnets in a single device.

Photon Shielding Characterization of a Modified Titania-Bismuth-Borotellurite Glass System for Medical Applications

Shielding against ionizing radiation is considered a crucial issue for the radiation safety of patients and workers at radiology centers. For this purpose, the shielding effectiveness of a modified titania-bismuth-borotellurite (TiO2-Bi2O3-B2O3-TeO2) glass system at diagnostic energy ranges was investigated. This glass system is characterized by the high density of its components and its non-toxicity, which have given it an outstanding reputation in radiation shielding. A comparison of shielding characteristics between different compositions of the mentioned glass system and shielding materials frequently used at radiology centers, including lead glass and ordinary concrete, is implemented. The computational program WinXCom was utilized to evaluate the mass attenuation coefficients (µ/ρ)m of the glass compositions, lead glass and ordinary concrete. The incident diagnostic X-ray photon beams used in imaging tools such as computed tomography (CT), dental imaging, general radiography and mammography were employed at average energies of 60, 40, 30, and 20 keV, respectively. Additional shielding parameters, such as half-value layers (HVLs) and effective atomic numbers (Zeff), were also computed. The results revealed that among the materials tested, the glass system with high bismuth-oxide content in (i.e., the 30Te sample) is the best shielding material for different diagnostic imaging tools. Such a transparent glass system could be advantageous, as it is considered a green and environmentally friendly shielding material that can replace undesirable toxic lead glass and ordinary concrete, which occupies a large amount of space at radiology centers.

Operation of photon diagnostic imagers for beam commissioning at the European XFEL.

X-ray photon beam diagnostic imagers are located at 24 positions in the European XFEL beam transport system to characterize the X-ray beam properties, and to give feedback for tuning and optimization of the electron acceleration and orbit, the undulators, and the X-ray optics. One year of commissioning allowed experience to be gained with these imagers, which will be reported here. The sensitive Spontaneous Radiation imager is useful for various investigations in spontaneous radiation mode: for undulator adjustments and for low-signal imaging applications. Thehigh-resolution Free-Electron Laser imager, 10 µm spatial resolution, is extensively used for the monitoring of beam position, spot size and shape, gain curve measurements, and also for beam-intensity monitoring. The wide field-of-view pop-in monitors (up to 200 mm) are regularly used for alignment and tuning of the various X-ray optical components like mirrors, slits and monochromators, and also for on-line beam control of a stable beam position at the instruments. The Exit Slit imager after the soft X-ray monochromator provides spectral information of the beam together with multi-channel plate based single-pulse gating. For particular use cases, these special features of the imagers are described. Some radiation-induced degradation of scintillators took place in this initial commissioning phase, providing useful information for better understanding of damage thresholds. Visible-light radiation in the beam pipe generated by upstream bending magnets caused spurious reflections in the optical system of some of the imagers which can be suppressed by aluminium-coated scintillating screens.