Static X-ray Imaging Research Articles

X-ray imaging scintillator: Tb3+-doped oxyfluoride aluminosilicate glass

Scintillators are considered as a vital component for X-ray imaging due to their ability to convert X-ray into visible light. We synthesized Tb3+-doped oxyfluoride aluminosilicate glass scintillators by conditional melt-quenching method. These glass scintillators possess outstanding optical and scintillating properties. All glass scintillators have high transparency (exceed 83.3% at 475 nm), excellent internal quantum yield and suitable lifetime. The integrated luminescent intensity of optimal specimen excited by X-ray is about 224% compared to Bi4Ge3O12 crystal. The optimal glass scintillator has a good stability after continuous X-ray irradiation and exhibits profound spatial resolution in X-ray image (20 lp·mm−1). All outcomes demonstrate that Tb3+-doped oxyfluoride aluminosilicate glass scintillators have potential application for static X-ray imaging.

The improved scintillation performances and X-ray imaging of Lu2O3:Pr3+ nanoparticles induced by Sm3+ doping

Lu2(1-x)Pr2xO3 nanoscintillators (x = 0.0005, 0.001, 0.0015, 0.003, 0.005) with excellent red emission and a response time of 185.7 μs were synthesized by a coprecipitation method. It is found that both photoluminescence and radioluminescence intensities show an initial rising and then decreasing trend with increasing Pr3+ concentration and the strongest intensity can be obtained at x = 0.001. By determining the average distance between Pr and O, the radiative transition processes from 3P0 and 1D2 to 3H4 and nonradiative transition process from 3P0 to 1D2 can be confirmed. Meanwhile, the afterglow level of Lu2O3:Pr3+ nanoscintillators with an average size of 112.3 nm was found to be 2190 ppm. Based on the spectral data and density functional theory calculations, the afterglow can be related to PrLu· traps due to the presence of Pr4+ in Lu2O3:Pr. When Sm3+ ions were doped into Lu2O3:Pr3+, it is found that it leads to the decreased creation of Pr4+, the reduced afterglow level and the improved radioluminescence. By means of Lu2O3:Pr3+, Sm3+ nanoparticles being dispersed into polymethyl methacrylate (PMMA) polymer, PMMA-Lu2O3:Pr3+, Sm3+ composite films with fast response time and radiation resistance were prepared by a rotating coating method. The static X-ray imaging with a spatial resolution of 5.5 lp/mm using the composite film as an imaging screen was realized at extremely low safe dose of 4.6 μGy. Meanwhile, for the broken electric wire used as an object, the clear X-ray image can be observed. Our results suggest that Lu2O3:Pr3+, Sm3+ nanoscintillators have potential applications in medical imaging and nondestructive testing.

Afterglow-Suppressed Lu2O3:Eu3+ Nanoscintillators for High-Resolution and Dynamic Digital Radiographic Imaging.

Lu2(1-x)Eu2xO3 nanoscintillators (x = 0.005, 0.01, 0.03, 0.05, 0.07, and 0.10) with red emission were synthesized by a coprecipitation method. It is found that their photo- and radioluminescence intensities increase with increasing Eu3+ concentration until x = 0.05. According to their concentration-dependent luminescence intensity ratios (I610(C2)/I582(S6)), the existing energy transfer from Eu3+(S6) (occupying S6 sites) to Eu3+(C2) (occupying C2 sites) can be confirmed. Based on the spectral data and density functional theory (DFT) calculations, the origin of Lu2O3:Eu3+ persistent luminescence at low concentration might be related to the tunneling processes between Eu3+ (occupying C2 and S6 sites) and oxygen interstitials (Oi×). After dispersing afterglow-suppressed Lu2O3:Eu3+ nanoscintillators into polymethyl methacrylate (PMMA) polymer-acetone solution, flexible PMMA-Lu2O3:Eu3+ composite films with high thermal stability and radiation resistance were fabricated by a doctor blade method. As the flexible composite film was used as an imaging plate, static X-ray images with high spatial resolution (5.5 lp/mm) under an extremely low dose of ∼1.1 μGyair can be acquired. When a watch with a moving second hand was used as an object, the dynamic X-ray imaging can be realized under a dose rate of 55 μGyair·s-1. Our results demonstrate that Lu2O3:Eu3+ nanoscintillators can be regarded as candidate materials for dynamic digital radiographic imaging.

Quantitative Imaging Parameters of Contrast-Enhanced Micro-Computed Tomography Correlate with Angiogenesis and Necrosis in a Subcutaneous C6 Glioma Model.

Simple SummaryContrast-enhanced (CE) X-ray imaging techniques have been used to assess angiogenesis in patients and animal models of cancer in order to overcome the limitations of histological quantification of angiogenesis, such as spatial and temporal heterogeneity of tumors. Some studies have compared the quantitative imaging parameters obtained with static and dynamic CE X-ray imaging techniques, but their association with histological biomarkers of angiogenesis has never been directly compared. This study aimed to provide such a comparison in a suitable animal model for the study of angiogenesis, namely, the subcutaneous C6 glioma model. We found an agreement among the quantitative imaging parameters obtained with these techniques, and we also found an association between a set of them with angiogenesis and necrosis descriptors. This set of quantitative imaging parameters demonstrated a high potential to describe angiogenesis and could be used to assess treatment response in further studies with this animal model.The aim of this work was to systematically obtain quantitative imaging parameters with static and dynamic contrast-enhanced (CE) X-ray imaging techniques and to evaluate their correlation with histological biomarkers of angiogenesis in a subcutaneous C6 glioma model. Enhancement (E), iodine concentration (CI), and relative blood volume (rBV) were quantified from single- and dual-energy (SE and DE, respectively) micro-computed tomography (micro-CT) images, while rBV and volume transfer constant (Ktrans) were quantified from dynamic contrast-enhanced (DCE) planar images. CI and rBV allowed a better discernment of tumor regions from muscle than E in SE and DE images, while no significant differences were found for rBV and Ktrans in DCE images. An agreement was found in rBV for muscle quantified with the different imaging protocols, and in CI and E quantified with SE and DE protocols. Significant strong correlations (Pearson r > 0.7, p < 0.05) were found between a set of imaging parameters in SE images and histological biomarkers: E and CI in tumor periphery were associated with microvessel density (MVD) and necrosis, E and CI in the complete tumor with MVD, and rBV in the tumor periphery with MVD. In conclusion, quantitative imaging parameters obtained in SE micro-CT images could be used to characterize angiogenesis and necrosis in the subcutaneous C6 glioma model.

Low-dose real-time X-ray imaging with nontoxic double perovskite scintillators

X-rays are widely used in probing inside information nondestructively, enabling broad applications in the medical radiography and electronic industries. X-ray imaging based on emerging lead halide perovskite scintillators has received extensive attention recently. However, the strong self-absorption, relatively low light yield and lead toxicity of these perovskites restrict their practical applications. Here, we report a series of nontoxic double-perovskite scintillators of Cs2Ag0.6Na0.4In1-yBiyCl6. By controlling the content of the heavy atom Bi3+, the X-ray absorption coefficient, radiative emission efficiency, light yield and light decay were manipulated to maximise the scintillator performance. A light yield of up to 39,000 ± 7000 photons/MeV for Cs2Ag0.6Na0.4In0.85Bi0.15Cl6 was obtained, which is much higher than that for the previously reported lead halide perovskite colloidal CsPbBr3 (21,000 photons/MeV). The large Stokes shift between the radioluminescence (RL) and absorption spectra benefiting from self-trapped excitons (STEs) led to a negligible self-absorption effect. Given the high light output and fast light decay of this scintillator, static X-ray imaging was attained under an extremely low dose of ∼1 μGyair, and dynamic X-ray imaging of finger bending without a ghosting effect was demonstrated under a low-dose rate of 47.2 μGyair s−1. After thermal treatment at 85 °C for 50 h followed by X-ray irradiation for 50 h in ambient air, the scintillator performance in terms of the RL intensity and X-ray image quality remained almost unchanged. Our results shed light on exploring highly competitive scintillators beyond the scope of lead halide perovskites, not only for avoiding toxicity but also for better performance.

Long-Term Results for Treatment of Chronic Ankle Instability With Fibular Periosteum Ligamentoplasty and Extensor Retinaculum Flap

Long-term results of anatomic reconstruction for chronic ankle instability are good, but no study has shown the results of fibular periosteum ligamentoplasty associated with extensor retinaculum flap at long-term follow-up. To demonstrate the efficacy of fibular periosteum ligamentoplasty and extensor retinaculum flap in chronic lateral instability, 40 patients underwent surgery for ankle instability. Thirty-three (82.5%) patients were reviewed, with a median follow-up duration of 8.2 (range 4 to 13) years. Functional results were assessed using the Karlsson score. Static and dynamic x-ray images were realized to measure varus tilt and anterior drawer, and osteoarthritis was evaluated with the van Dijk classification. The median Karlsson score was 95 (range 80 to 100). The mean decrease in varus laxity was 11° (range 0 to 18) and in anterior drawer was 1 (range -8 to 4) mm. At the last follow-up visit, 3 (7.5%) patients showed an evidence of osteoarthritis according to the preoperative criteria of the van Dijk classification (grade 2) and 6 (15%) patients had radiologic changes, without narrowing of the joint space (grade 1). Studies that have a follow-up time >5 years are rare. This study shows that despite the excellent control of ankle laxity, severe radiographic changes (grade 2) continue to evolve in the long term. This study indicates a good long-term outcome but suggests the need to monitor the occurrence of osteoarthritis over the long term.

MODELLING ERRORS IN X-RAY FLUOROSCOPIC IMAGING SYSTEMS USING PHOTOGRAMMETRIC BUNDLE ADJUSTMENT WITH A DATA-DRIVEN SELF-CALIBRATION APPROACH

Abstract. X-ray imaging is a fundamental tool of routine clinical diagnosis. Fluoroscopic imaging can further acquire X-ray images at video frame rates, thus enabling non-invasive in-vivo motion studies of joints, gastrointestinal tract, etc. For both the qualitative and quantitative analysis of static and dynamic X-ray images, the data should be free of systematic biases. Besides precise fabrication of hardware, software-based calibration solutions are commonly used for modelling the distortions. In this primary research study, a robust photogrammetric bundle adjustment was used to model the projective geometry of two fluoroscopic X-ray imaging systems. However, instead of relying on an expert photogrammetrist’s knowledge and judgement to decide on a parametric model for describing the systematic errors, a self-tuning data-driven approach is used to model the complex non-linear distortion profile of the sensors. Quality control from the experiment showed that 0.06 mm to 0.09 mm 3D reconstruction accuracy was achievable post-calibration using merely 15 X-ray images. As part of the bundle adjustment, the location of the virtual fluoroscopic system relative to the target field can also be spatially resected with an RMSE between 3.10 mm and 3.31 mm.

A high-speed two-frame, 1-2 ns gated X-ray CMOS imager used as a hohlraum diagnostic on the National Ignition Facility (invited).

A novel x-ray imager, which takes time-resolved gated images along a single line-of-sight, has been successfully implemented at the National Ignition Facility (NIF). This Gated Laser Entrance Hole diagnostic, G-LEH, incorporates a high-speed multi-frame CMOS x-ray imager developed by Sandia National Laboratories to upgrade the existing Static X-ray Imager diagnostic at NIF. The new diagnostic is capable of capturing two laser-entrance-hole images per shot on its 1024 × 448 pixels photo-detector array, with integration times as short as 1.6 ns per frame. Since its implementation on NIF, the G-LEH diagnostic has successfully acquired images from various experimental campaigns, providing critical new information for understanding the hohlraum performance in inertial confinement fusion (ICF) experiments, such as the size of the laser entrance hole vs. time, the growth of the laser-heated gold plasma bubble, the change in brightness of inner beam spots due to time-varying cross beam energy transfer, and plasma instability growth near the hohlraum wall.

Luminescence properties of Tb3+-doped borosilicate scintillating glass under UV excitation

Transparent Li2O–BaO–La2O3–Al2O3–B2O3–SiO2 glasses doped with Tb3+ ion were prepared by high temperature melting method. Luminescence properties of Tb3+-doped borosilicate glasses have been investigated by transmission, excitation, emission and luminescence decay measurements. The transmission spectrum shows the glass has good transmittance in the visible region. Under the 236nm UV excitation the intense green emission from 5D4 level is observed in Tb3+-doped borosilicate glass, comparable in intensity to the violet–blue emission starting from the 5D3 level. The green emission intensity of Tb3+ ion firstly increases and then decreases with the decreasing B2O3/SiO2 ratio in glass matrix. 5D4→7FJ (J=6, 5, 4 and 3) transitions of Tb3+ ion in borosilicate glass are greatly enhanced with increasing concentration of Tb3+ through the cross relaxation [Tb3+ (5D3)+Tb3+ (7F6)→Tb3+ (5D4)+Tb3+ (7F0)] between two Tb3+ ions. Luminescence decay time of 2.13ms is obtained for the emission transitions starting from 5D4 level in 2.5Li2O–20BaO–20La2O3–2.5Al2O3–20B2O3–35SiO2–0.5Tb4O7 glass. The results show that Tb3+-doped borosilicate glasses would be potential candidates for scintillating material for static X-ray imaging.

神光Ⅲ主机装置X光静态成像系统研制

神光Ⅲ主机装置X光静态成像系统研制

Soft x-ray images of the laser entrance hole of ignition hohlraums

Hohlraums are employed at the national ignition facility to convert laser energy into a thermal x-radiation drive, which implodes a fusion capsule, thus compressing the fuel. The x-radiation drive is measured with a low spectral resolution, time-resolved x-ray spectrometer, which views the region around the hohlraum's laser entrance hole. This measurement has no spatial resolution. To convert this to the drive inside the hohlraum, the size of the hohlraum's opening ("clear aperture") and fraction of the measured x-radiation, which comes from this opening, must be known. The size of the clear aperture is measured with the time integrated static x-ray imager (SXI). A soft x-ray imaging channel has been added to the SXI to measure the fraction of x-radiation emitted from inside the clear aperture. A multilayer mirror plus filter selects an x-ray band centered at 870 eV, near the peak of the x-ray spectrum of a 300 eV blackbody. Results from this channel and corrections to the x-radiation drive are discussed.

Effect of Tb 3+ concentration and sensitization of Ce 3+ on luminescence properties of terbium doped phosphate scintillating glass

Phosphate glasses doped with different concentrations of Ce 3+ and Tb 3+ were prepared by high temperature melting method. Effects of Tb 3+ concentration and sensitization of Ce 3+ on photoluminescence and radio-luminescence properties of terbium doped phosphate glass have been investigated by absorption, excitation and emission spectroscopy. Results showed the phosphate glass exhibit high broad absorption band attribute to the allowed 4f 8–4f 75d transition of Tb 3+, which is beneficial for the 542 nm emission of Tb 3+. It is found that the emission intensity of Tb 3+ at 542 nm increased as the concentration of Tb 3+ and Ce 3+increasing. The suitable concentration of Ce 3+ and Tb 3+ in phosphate glass is 2 mol% and 10 mol% respectively, and the emission intensity of Ce 3+/Tb 3+-codoped phosphate glass at 542 nm shows 8 times stronger than that of the commercial Bi 4Ge 3O 12 (BGO) crystal at 500 nm. The phosphate glass doped with Ce 3+ and Tb 3+ ions would be potential candidates for scintillating material for static X-ray imaging.

Images of the laser entrance hole from the static x-ray imager at NIF

The static x-ray imager at the National Ignition Facility is a pinhole camera using a CCD detector to obtain images of Hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters, combined with the CCD response, allow recording images in the x-ray range of 3-5 keV with 60 μm spatial resolution. The routines used to obtain the apparent size of the backlit LEH and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition Hohlraum) is discussed.

Effect of cervical dynamics on adjacent segment degeneration after anterior cervical fusion with cages

The objective of this study is to evaluate the effect of anterior cervical discectomy and fusion (ACDF) on the motion of the cervical spine and dynamic stress (tendency to kyphosis) on adjacent segments and on the overall spinal alignment which may predispose to symptomatic disc diseases at other levels. Twenty consecutive patients underwent ACDF with a mean follow-up of 28 months (range 13-38). Preoperative and postoperative clinical assessments were done by using the neck disability index (NDI) and the Japanese Orthopedic Association (JOA) score. In all cases, at the last follow-up control, a neuro-radiographic assessment [cervical spine static and dynamic X-ray and magnetic resonance imaging (MRI)] was done. The angle of the operated disc space, the disc space angle of contiguous segments, and their range of motion (ROM) and the kyphotic Cobb angle (C2-7) were measured by computer software. The study was done at Sant'Andrea Hospital, Rome, Italy in the period from November 2003 to November 2005. We observed that: the mean Cobb angle improved significantly (p < 0.001) from 3.4 degrees (kyphosis) to postoperative 14.5 degrees. This normalization of angle showed a direct effect on improvement of myelopathic patients, but it had a statistically nonsignificant effect on adjacent segments degeneration (ASD). The mean segmental ROM of adjacent segments did not show significant instability. The mean was 11.1 degrees at upper and 10.2 degrees at lower levels (close to normal). In six cases, the ROM was higher than normal: five of these patients demonstrated symptomatic adjacent segment pathology. Postoperative improvement of mean JOA and NDI scores was statistically significant (p < 0.001). Anyway, symptomatic ASD was observed in five patients (20%): in four of them, the higher disc spaces and in one, the lower disc spaces were involved. In four cases, the preoperative MRI showed slight and asymptomatic disc degeneration at the same levels involved subsequently. This ASD was significantly related to the increased ROM at the segments involved. Follow-up X-rays showed solid fusion with absence of movement in all but one case (at 13-month follow-up), who showed slight movement in the operated level in spite of clinical improvement. The follow-up MRI showed, in all cases, good decompression in the treated levels. Compensatory increase in ROM of the contiguous motion segments in patients subjected to ACDF may lead to ASD especially in those cases with asymptomatic adjacent subclinical degenerative disease. If these preliminary results will be confirmed by larger series, it could be reasonable in young selected patients with soft disc herniation to adopt total disc arthroplasty instead of fusion after cervical micro-discectomy.

Flat field anomalies in an x-ray charge coupled device camera measured using a Manson x-ray source

The static x-ray imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the x rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The charge coupled device (CCD) chip is an x-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 microm square pixels, and 15 microm thick. A multianode Manson x-ray source, operating up to 10 kV and 10 W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/DeltaE approximately = 10. The x-ray beam intensity was measured using an x-ray photodiode that has an accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The x-ray beam provides full CCD illumination and is flat, within +/-1% maximum to minimum. The spectral efficiency was measured at ten energy bands ranging from 930 to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an x-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

Method for reducing noise in X-ray images by averaging pixels based on the normalized difference with the relevant pixel

A real-time digital filter for noise reduction in X-ray images is proposed. The filter is based on averaging of only similar pixels (pixels that differ only little) rather than neighboring pixels, which are averaged in conventional linear low-pass filters. The effectiveness of the filter was evaluated by computer simulation, where original images that were acquired by X-ray exposure were processed in accordance with the filter algorithm. The resulting images were evaluated in terms of the pre-sampled modulation transfer function (MTF), the noise power spectrum (NPS), and the lag. Comparison of the filtered and original images revealed that the NPS was reduced for the full range of spatial frequencies in the filtered image, resulting in a reduction of total noise power to about 1/9 the level in the original image with no degradation in the MTF or lag. The usefulness of the filter was demonstrated in fluoroscopic, digital subtraction angiography (DSA) and mammographic phantom studies. The filter was found to have the potential to reduce the patient dose by reducing the noise in dynamic as well as static X-ray images.

Direct-drive, cryogenic target implosions on OMEGA

Direct-drive spherical implosions of cryogenic, D2-filled capsules are performed on the 60-beam OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)]. The targets are energy scaled from the base line ignition design developed for the National Ignition Facility [W. J. Hogan et al., Nucl. Fusion 41, 567 (2001)]. Thin-walled (∼4μm), ∼860μm diam deuterated polymer shells are permeation filled with D2 gas and cooled to the triple point (∼18.7K). Cryogenic ice layers with a uniformity of ∼2μm rms are formed and maintained. The targets are imploded with high-contrast pulse shapes with full single-beam smoothing (1THz bandwidth, two-dimensional smoothing by spectral dispersion with polarization smoothing) to study the effects of the acceleration- and deceleration-phase Rayleigh–Taylor growth on target performance. Two-dimensional hydrocode simulations show good agreement with the experimental observations. Scattered-light and neutron-burn-history measurements are consistent with predicted absorption and hydrodynamic coupling calculations. Time-resolved and static x-ray images show the progress of the imploding shell, the shape, and temperature of the stagnating core. Particle-based instruments measure the fusion yield and rate, the ion temperature in the core, and the fuel areal density at the time of neutron production. These experiments have produced fuel areal densities of up to ∼100mg∕cm2, primary neutron yields of ∼4×1010, and secondary neutron yields of 1% to 2% of the primary yield. These results validate the hydrocode predictions for the direct-drive ignition-point design, giving increasing confidence in the direct-drive approach to inertial confinement fusion ignition.

Direct-drive cryogenic target implosion performance on OMEGA

Layered and characterized cryogenic D2 capsules have been imploded using high-contrast pulse shapes on the 60-beam OMEGA laser at the Laboratory for Laser Energetics [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. These experiments measure the sensitivity of the direct-drive implosion performance to parameters such as the inner-ice-surface roughness, the adiabat of the fuel during the implosion, and the laser power balance. The goal is to demonstrate a high neutron-averaged fuel ρR with low angular variance using a scaled, α∼3 ignition pulse shape driving a scaled all-DT ignition capsule. Results are reported with improvements in target layering and characterization and in laser pointing and target positioning on the OMEGA laser over previous experiments [T. C. Sangster et al., Phys. Plasmas 10, 1937 (2003)]. These capsules have been imploded using up to 23 kJ of 351-nm laser light with an on-target energy imbalance of less than 2% rms, full beam smoothing (1-THz bandwidth, two-dimensional smoothing by spectral dispersion, and polarization smoothing), and new, optimized, distributed phase plates. Pulse shapes include high-adiabat (∼25) square pulses and low-adiabat (&amp;lt;5) shaped pulses. The data from neutron and charged-particle diagnostics, as well as static and time-resolved x-ray images of the imploding core, are compared with one- and two-dimensional numerical simulations. Scaling of target performance to a weighted quadrature of inner-ice roughness at the end of the acceleration phase is investigated.

Design of the National Ignition Facility static x-ray imager

Two static x-ray imagers (SXI) will be used to monitor beam pointing on all target shots in the National Ignition Facility. These pinhole-based instruments will provide time integrated two-dimensional images of target x-ray emissions in the energy range between 2 and 3 keV. These instruments are not DIM based and will view along dedicated lines of sight from near the top and bottom ports of the target chamber. Beams that miss or clip the hohlraum laser-entrance holes will produce x-ray emission on the ends of the hohlraum, indicating improper beam pointing and/or target positioning. The SXIs will also be used to quantify beam focusing and pointing by producing x-ray images of dedicated test targets irradiated by focused beams at precalculated positions. A proposed design is presented, along with supporting data from NOVA target experiments.

Comparison of quantitative x-ray imaging and raster probing in heart cells exposed to sodium-free media

Quantitative biological electron probe x-ray microanalysis (EPXMA) ideally makes use of two approaches in examination of samples: static raster probing and quantitative x-ray imaging. Efficient use of expensive microanalytical equipment requires intelligent decisions on the appropriate strategy for optimizing data collection. A low resolution, short dwell time map (for example, 64 × 64 pixels by 2 seconds) may survey one to several cells at low magnification and provide adequate statistics for most structures and elements. Elements, notably Ca, present in low concentrations within small regions may require the acquisition equivalent of long static raster probes, increased numbers of images from low resolution maps, higher resolution maps, longer dwell time maps, or a combination of these options.We examined raster probe and mapping results in cultured heart cells. In these cells EXPMA has been demonstrated to be an appropriate tool to observe the results of perturbation of the Na-Ca gradient, brought about by incubation of cells in low Na or Na-free media.