Low-dose X-ray Research Articles

Efficient labeling for fine-tuning chest X-ray bone-suppression networks for pediatric patients.

Pneumonia, a major infectious cause of morbidity and mortality among children worldwide, is typically diagnosed using low-dose pediatric chest X-ray [CXR (chest radiography)]. In pediatric CXR images, bone occlusion leads to a risk of missed diagnosis. Deep learning-based bone-suppression networks relying on training data have enabled considerable progress to be achieved in bone suppression in adult CXR images; however, these networks have poor generalizability to pediatric CXR images because of the lack of labeled pediatric CXR images (i.e., bone images vs. soft-tissue images). Dual-energy subtraction imaging approaches are capable of producing labeled adult CXR images; however, their application is limited because they require specialized equipment, and they are infrequently employed in pediatric settings. Traditional image processing-based models can be used to label pediatric CXR images, but they are semiautomatic and have suboptimal performance. We developed an efficient labeling approach for fine-tuning pediatric CXR bone-suppression networks capable of automatically suppressing bone structures in CXR images for pediatric patients without the need for specialized equipment and technologist training. Three steps were employed to label pediatric CXR images and fine-tune pediatric bone-suppression networks: distance transform-based bone-edge detection, traditional image processing-based bone suppression, and fully automated pediatric bone suppression. In distance transform-based bone-edge detection, bone edges were automatically detected by predicting bone-edge distance-transform images, which were then used as inputs in traditional image processing. In this processing, pediatric CXR images were labeled by obtaining bone images through a series of traditional image processing techniques. Finally, the pediatric bone-suppression network was fine-tuned using the labeled pediatric CXR images. This network was initially pretrained on a public adult dataset comprising 240 adult CXR images (A240) and then fine-tuned and validated on 40 pediatric CXR images (P260_40labeled) from our customized dataset (named P260) through five-fold cross-validation; finally, the network was tested on 220 pediatric CXR images (P260_220unlabeled dataset). The distance transform-based bone-edge detection network achieved a mean boundary distance of 1.029. Moreover, the traditional image processing-based bone-suppression model obtained bone images exhibiting a relative Weber contrast of 93.0%. Finally, the fully automated pediatric bone-suppression network achieved a relative mean absolute error of 3.38%, a peak signal-to-noise ratio of 35.5dB, a structural similarity index measure of 98.1%, and a bone-suppression ratio of 90.1% on P260_40labeled. The proposed fully automated pediatric bone-suppression network, together with the proposed distance transform-based bone-edge detection network, can automatically acquire bone and soft-tissue images solely from CXR images for pediatric patients and has the potential to help diagnose pneumonia in children.

Cationic Metal-Organic Layer Delivers siRNAs to Overcome Radioresistance and Potentiate Cancer Radiotherapy.

Radiotherapy plays an important role in modern oncology, but its treatment efficacy is limited by the radioresistance of tumor cells. As a member of the inhibitor of apoptosis protein family, survivin plays a key role in developing radioresistance by mediating apoptosis evasion, promoting epithelial-mesenchymal transition, and modulating cell cycle dynamics. Efficient downregulation of survivin expression presents a promising strategy to enhance the antitumor effects of radiotherapy. Herein, we report the design of a hafnium-porphyrin-based cationic metal-organic layer (CMOL) with quaternary ammonium capping groups to deliver small interfering RNAs (siRNAs) for enhanced radiotherapy. The CMOL@siRNA nanoplatform not only increased energy deposition from X-rays and reactive oxygen species generation via a unique radiotherapy-radiodynamic therapy process, but also effectively delivered siRNAs to downregulate survivin expression and ameliorate radioresistance of cancer cells. Consequently, CMOL@siRNA in combination with low-dose X-ray irradiation demonstrated remarkable antitumor efficacy with 96.9% and 91.4% tumor growth inhibition in murine colorectal carcinoma and triple-negative breast cancer models, respectively.

Restoration of X-ray phase-contrast imaging based on generative adversarial networks

For light-element materials, X-ray phase contrast imaging provides better contrast compared to absorption imaging. While the Fourier transform method has a shorter imaging time, it typically results in lower image quality; in contrast, the phase-shifting method offers higher image quality but is more time-consuming and involves a higher radiation dose. To rapidly reconstruct low-dose X-ray phase contrast images, this study developed a model based on Generative Adversarial Networks (GAN), incorporating custom layers and self-attention mechanisms to recover high-quality phase contrast images. We generated a simulated dataset using Kaggle’s X-ray data to train the GAN, and in simulated experiments, we achieved significant improvements in Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM). To further validate our method, we applied it to fringe images acquired from three phase contrast systems: a single-grating phase contrast system, a Talbot-Lau system, and a cascaded grating system. The current results demonstrate that our method successfully restored high-quality phase contrast images from fringe images collected in experimental settings, though it should be noted that these results were achieved using relatively simple sample configurations.

Application of FISH based G2-PCC assay for the cytogenetic assessment of high radiation dose exposures: Potential implications for rapid triage biodosimetry.

The main goal of this study is to test the utility of calyculin A induced G2-PCC assay as a biodosimetry triage tool for assessing a wide range of low and acute high radiation dose exposures of photons. Towards this initiative, chromosome aberrations induced by low and high doses of x-rays were evaluated and characterized in G2-prematurely condensed chromosomes (G2-PCCs) by fluorescence in situ hybridization (FISH) using human centromere and telomere specific PNA (peptide nucleic acid) probes. A dose dependent increase in the frequency of dicentric chromosomes was observed in the G2-PCCs up to 20 Gy of x-rays. The combined yields of dicentrics and rings in the G2-PCCs showed a clear dose dependency up to 20 Gy from 0.02/cell for 0.1 Gy to 14.98/cell for 20 Gy. Centric rings were observed more frequently than acentric ring chromosomes in the G2-PCCs at all the radiation doses from 1 Gy to 20 Gy. A head-to-head comparison was also performed by FISH on the yields of chromosome aberrations induced by different doses of x-rays (0 Gy -7.5 Gy) in colcemid arrested metaphase chromosomes and calyculin A induced G2-PCCs. In general, the frequencies of dicentrics, rings and acentric fragments were slightly higher in G2-PCCs than in colcemid arrested metaphase chromosomes at all the radiation doses, but the differences were not statistically significant. To reduce the turnaround time for absorbed radiation dose estimation, attempt was made to obtain G2-PCCs by reducing the culture time to 36 hrs. The absorbed doses estimated in x-rays irradiated (0,1,2 and 4 Gy) G2-PCCs after 36 hrs of culture were grossly like that of G2-PCCs and colcemid arrested metaphase chromosomes prepared after 48 hrs of culture. Our study indicates that the shortened version of calyculin A induced G2-PCC assay coupled with the FISH staining technique can serve as an effective triage biodosimetry tool for large-scale radiological/nuclear incidents.

The Induction of Drug Uptake Transporter Organic Anion Transporting Polypeptide 1A2 by Radiation Is Mediated by the Nonreceptor Tyrosine Kinase v-YES-1 Yamaguchi Sarcoma Viral Oncogene Homolog 1.

Organic anion transporting polypeptides (OATP, gene symbol SLCO) are well-recognized key determinants for the absorption, distribution, and excretion of a wide spectrum of endogenous and exogenous compounds including many antineoplastic agents. It was therefore proposed as a potential drug target for cancer therapy. In our previous study, it was found that low-dose X-ray and carbon ion irradiation both upregulated the expression of OATP family member OATP1A2 and in turn, led to a more dramatic killing effect when cancer cells were cotreated with antitumor drugs such as methotrexate. In the present study, the underlying mechanism of the phenomenon was explored in breast cancer cell line MCF-7. It was found that the nonreceptor tyrosine kinase v-YES-1 Yamaguchi sarcoma viral oncogene homolog 1 (YES-1) was temporally coordinated with the change of OATP1A2 after irradiation. The overexpression of YES-1 significantly increased OATP1A2 both at the mRNA and protein level. The signal transducer and activator of transcription 3 (STAT3) pathway is likely the downstream target of YES-1 because phosphorylation and nuclear accumulation of STAT3 were both enhanced after overexpressing YES-1 in MCF-7 cells. Further investigation revealed that there are two possible binding sites of STAT3 localized at the upstream sequence of SLCO1A2, the encoding gene of OATP1A2. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis suggested that these two sites bound to STAT3 specifically and the overexpression of YES-1 significantly increased the association of the transcription factor with the putative binding sites. Finally, inhibition or knockdown of YES-1 attenuated the induction effect of radiation on the expression of OATP1A2. SIGNIFICANCE STATEMENT: The present study found that the effect of X-rays on v-YES-1 Yamaguchi sarcoma viral oncogene homolog 1 (YES-1) and organic anion transporting polypeptides (OATP)1A2 was temporally coordinated. YES-1 phosphorylates and increases the nuclear accumulation of signal transducer and activator of transcription 3, which in turn binds to the upstream regulatory sequences of SLCO1A2, the coding gene for OATP1A2. Hence, inhibitors of YES-1 may suppress the radiation induction effect on OATP1A2.

Effect of FBG Fiber Dosimeter Division in Sensing Capability for Low Radiation Doses

ر A fiber Bragg grating (FBG) as a dosimeter is developed in this simulation study (based on Optisystem 21 software) by dividing its region into five individual regions. The division includes the same properties for all regions, which is a standard SiO2 optical fiber material. In dosimeters, it is convenient to introduce dopants to increase the fiber sensitivity. The new design accepts dopants and can work without such a dopant. Measurements for sensing deflected signals from the FBG sensor confirmed increased sensitivity for low-rate radiation doses in comparison to one bulk region in a traditional fiber dosimeter. The sensitivity of this dosimeter is based on both the FWHM line shape function and the amplitude of the deflected signals. The FBG dosimeter sensor can respond to low-dose radiation in a noticeable manner according to the type of applied simulated effect. Dosimeter body division for multi-regions gives rise to sensitivity in comparison to the traditional bulk region. The measured FWHM from the line-shape function for overall observed signals fluctuates from 0.374 MHz under applied temperature, stress x, y, z, and strain to 0.358, 0.373, 0.3733, 0.368, and 0.3737 MHz, respectively. While this range follows different fitting functions: Sin, Exp.Decay, SinSqu., Exp.Decay3, and GaussAmpl. For last effects, according to measured effect. The same measurements were carried out for signal amplitude variation, with these effects giving a variety of relationships indicating their existing contribution. Results confirmed an efficient tool for use in sensing for low x-ray and gamma ray radiation dose applications versus traditional bulk FBG sensor type.

Bifunctional Metal-Organic Framework Synergistically Enhances Radiotherapy and Activates STING for Potent Cancer Radio-Immunotherapy.

The activation of the stimulator of interferon genes (STING) protein by cyclic dinucleotide metabolites plays a critical role in antitumor immunity. However, synthetic STING agonists like 4-(5,6-dimethoxybenzo[b]thiophen-2-yl)-4-oxobutanoic acid (MSA-2) exhibit suboptimal pharmacokinetics and fail to sustain STING activation in tumors for effective antitumor responses. Here, we report the design of MOF/MSA-2, a bifunctional MSA-2 conjugated nanoscale metal-organic framework (MOF) based on Hf6 secondary building units (SBUs) and hexakis(4'-carboxy[1,1'-biphenyl]-4-yl)benzene bridging ligands, for potent cancer radio-immunotherapy. By leveraging the high-Z properties of the Hf6 SBUs, the MOF enhances the therapeutic effect of X-ray radiation and elicits potent immune stimulation in the tumor microenvironment. MOF/MSA-2 further enhances radiotherapeutic effects of X-rays by enabling sustained STING activation and promoting the infiltration and activation of immune cells in the tumors. MOF/MSA-2 plus low-dose X-ray irradiation elicits strong STING activation and potent tumor regression, and when combined with an immune checkpoint inhibitor, effectively suppresses both primary and distant tumors through systemic immune activation.

Impact of low-dose X-ray radiation on the lipidome of Chlorella vulgaris

Impact of low-dose X-ray radiation on the lipidome of Chlorella vulgaris

Residual encoder-decoder based architecture for medical image denoising

AbstractHigh-resolution computed tomography (CT) scans require high doses of X-rays, posing potential health risks to patients, including genetic damage and cancer. Conversely, low doses of X-rays result in noise and artifacts in the reconstructed CT scans. Consequently, the problem of denoising low-dose CT (LDCT) images has become a critical yet challenging issue in the field of CT imaging. However, existing deep learning-based LDCT image denoising methods frequently result in the loss of high-frequency features, such as edges and textures, due to the use of mean squared error loss. To address this issue, we propose a method based on high-frequency feature learning to enhance the denoising performance of existing models. Our method is designed to simultaneously learn the primary task of LDCT image denoising and the auxiliary task of LDCT edge detection, thereby improving the denoising performance without increasing the number of model parameters and the inference time. Our method significantly improves the denoising performance of the RED-CNN model, achieving competitive results compared to state-of-the-art denoising models on the AAPM and Qin-LUNG-CT datasets.

Biodegradable copper-iodide clusters modulate mitochondrial function and suppress tumor growth under ultralow-dose X-ray irradiation

Both copper (Cu2+/+) and iodine (I−) are essential elements in all living organisms. Increasing the intracellular concentrations of Cu or I ions may efficiently inhibit tumor growth. However, efficient delivery of Cu and I ions into tumor cells is still a challenge, as Cu chelation and iodide salts are highly water-soluble and can release in untargeted tissue. Here we report mitochondria-targeted Cu-I cluster nanoparticles using the reaction of Cu+ and I− to form stable bovine serum albumin (BSA) radiation-induced phosphors (Cu-I@BSA). These solve the stability issues of Cu+ and I− ions. Cu-I@BSA exhibit bright radioluminescence, and easily conjugate with the emission-matched photosensitizer and targeting molecule using functional groups on the surface of BSA. Investigations in vitro and in vivo demonstrate that radioluminescence under low-dose X-ray irradiation excites the conjugated photosensitizer to generate singlet oxygen, and combines with the radiosensitization mechanism of the heavy atom of iodine, resulting in efficient tumor inhibition in female mice. Furthermore, our study reveals that BSA protection causes the biodegradable Cu-I clusters to release free Cu and I ions and induce cell death by modulating mitochondrial function, damaging DNA, disrupting the tricarboxylic acid cycle, decreasing ATP generation, amplifying oxidative stress, and boosting the Bcl-2 pathway.

Lead-Free Perovskite With Efficient Tellurium Ion Activation for Multifunctional Applications.

Lead-free perovskite materials have received extensive attention due to their non-toxicity, super environmental stability and adjustable photoelectric properties. However, the inherent problems of low luminous efficiency and low photoluminescence quantum yields (PLQYs) limit its development in multifunctional applications. Here, Te4+ doped Cs2ZrCl6 with high luminous efficiency and stability for multifunctional applications are developed. Te4+ ions are used as emission centers to improve the optical properties of Cs2ZrCl6 to make efficient and stable single-component white light-emitting diodes (WLEDs), and can be used as scintillator materials to improve scintillation performance to achieve high-resolution and low-dose X-ray imaging detection. In addition, it is found for the first time that Te4+ ions can be introduced into the trap center, so that the Cs2ZrCl6:Te4+ perovskite material exhibits excellent persistent luminescence (PersL) and mechanoluminescence (ML) after X-ray radiation, which has potential applications in the fields of delayed imaging and stress sensing. This work provides a method for designing lead-free perovskites with high optical performance and scintillating properties, as well as developing multifunctional applications.

Characterization of a new low-dose and low-energy Gafchromic film LD-V1.

To characterize the dose-response, energy dependence, postexposure changes, orientation dependence, and spatial capabilities of LD-V1, a new low-dose Gafchromic film for low-energy x-ray dosimetry. A single sheet of LD-V1 Gafchromic film was cut into 15 × 20mm2 rectangles with a notch to track orientation. Eight different doses between 5 and 320mGy were delivered by an MXR-160/22 x-ray tube using x-ray beams of 90, 100, and 120kVp filtered with 3mm of Al and 2mm of Ti. The 120kVp films were scanned at 1, 1.5, 2, 3, 12, 24, 48, 72, and 168h postexposure in portrait orientation and additionally scanned in landscape orientation at 24h. The 90 and 100kVp films were scanned at 24h postexposure in portrait orientation. Lastly, a 20 × 200mm2 strip of film was irradiated using a thin-slit imaging collimator and scanned 24h postexposure to test the film performance in an x-ray imaging application. Of the three color channels, the red channel was found to produce a dose-response curve with a large range of net optical density (netOD) values across the considered dose range. A prominent energy dependence was discovered, resulting in dose discrepancies on the scale of 17mGy between 90 and 120kVp for a dose of 80mGy. The measured postexposure changes suggest that the calibration irradiation-to-scan time should be longer than 12h with a±4h scanning time window for dose errors of<0.5%. An average dose difference of 3.4% was found between the two scanning orientations. Lastly, noise of 4% was measured in the thin slit collimator film for a dose of 30mGy. We have characterized the LD-V1 film for low-energy, low-dose x-ray dosimetry. Energy, scan-time, and orientation dependencies should be considered when using this film.

Digitonin-Loaded Nanoscale Metal-Organic Framework for Mitochondria-Targeted Radiotherapy-Radiodynamic Therapy and Disulfidptosis.

The efficacy of radiotherapy (RT) is limited by inefficient X-ray absorption and reactive oxygen species generation, upregulation of immunosuppressive factors, and a reducing tumor microenvironment (TME). Here, the design of a mitochondria-targeted and digitonin (Dig)-loaded nanoscale metal-organic framework, Th-Ir-DBB/Dig, is reported to overcome these limitations and elicit strong antitumor effects upon low-dose X-ray irradiation. Built from Th6O4(OH)4 secondary building units (SBUs) and photosensitizing Ir(DBB)(ppy)2 2+ (Ir-DBB, DBB=4,4'-di(4-benzoato)-2,2'-bipyridine; ppy=2-phenylpyridine) ligands, Th-Ir-DBB exhibits strong RT-radiodynamic therapy (RDT) effects via potent radiosensitization with high-Z SBUs for hydroxyl radical generation and efficient excitation of Ir-DBB ligands for singlet oxygen production. Th-Ir-DBB/Dig releases digitonin in acidic TMEs to trigger disulfidptosis of cancer cells and sensitize cancer cells to RT-RDT through glucose and glutathione depletion. The released digitonin simultaneously downregulates multiple immune checkpoints in cancer cells and T cells through cholesterol depletion. As a result, Th-Ir-DBB/dig plus X-ray irradiation induces strong antitumor immunity to effectively inhibit tumor growth in mouse models of colon and breast cancer.

Effects of Low-Dose X-Ray Exposure on Hematological Parameters In Vivo

Background: High levels of IR are known to induce cancer and disrupt biological processes through oxidative damage primarily driven by reactive oxygen species (ROS) overproduction. This study aims to investigate the effects of low-dose X-ray exposure on Hematologic parameters in Wistar albino rats, contributing to the limited literature on low-dose X-ray exposure and its impacts on liver health. Methods: Adult male Wistar albino rats, averaging 150 ± 25 g, were divided into four experimental groups. The rats underwent irradiation using a 6 MV linear accelerator, and blood samples were collected for biochemical analysis. Hematologic parameters, including Red Blood Cells (RBCs), platelets (PLTs), hemoglobin (Hb), white blood cells (WBCs), lymphocytes (LY), and granulocytes (GRAN), were assessed. Results: Significant variations in hematologic parameters were observed based on the method and dosage of radiation. The RBC count decreased from 9.15 ± 0.21 (control) to 3.32 ± 0.25 (higher dosage), a reduction of 58.93%. Platelet counts dropped by 51.43% and 32.46% for single and fragmented dosage approaches, respectively. Moreover, WBC and granulocyte counts were significantly reduced, with hemoglobin levels declining by 47.52% and 57.34% following specific irradiation rates (p &lt; 0.001). Conclusion: The findings underscore the adverse effects of ionizing radiation on hematologic parameters, indicating that low-dose X-ray exposure does not promote an adaptive response in hematology when followed by higher radiation doses.

High Bioavailability of Spinach Folate Evaluated by Functional Biomarkers in a Folate Depletion-Repletion Mouse Model.

The bioavailability of natural folates is 50% lower than that of synthetic folic acid (FA); however, it remains unclear whether this value is universally applicable to all foods. Therefore, the present study investigated the bioavailability of folate from spinach using multiple biomarkers in a folate depletion-repletion mouse model. Mice were fed a folate-deficient diet for 4 wk and subsequently divided into three groups: folate-deficient, FA, and spinach folate. The folate repletion group received either FA or spinach folate at 2 mg/kg diet for 9 d. On the 7th day of repletion, half of each group underwent low-dose total body X-ray irradiation to induce chromosomal damage in bone marrow. Folate bioavailability biomarkers included measurements of folate levels in plasma, liver, and bone marrow along with an analysis of plasma homocysteine levels and chromosome damage, both of which are functional biomarkers of body folate. The consumption of a folate-deficient diet led to decreased tissue folate levels, increased plasma homocysteine levels, and chromosomal damage. Repletion with spinach folate restored folate levels in plasma, liver, and bone marrow to 69, 13, and 68%, respectively, of FA levels. Additionally, spinach folate repletion reduced plasma homocysteine levels and chromosome damage to 83% and 93-117%, respectively, of FA levels. Collectively, the present results demonstrated that the bioavailability of spinach folate exceeded 83% of FA, particularly when assessed using functional biomarkers.

Salt induced slowdown of kinetics and dynamics during thermal gelation of egg-yolk.

We investigated the effect of the NaCl concentration (0.3-2M) on the structure and dynamics of hen egg yolk at room temperature and during thermal gelation at temperatures in the range of 66-90 °C utilizing low-dose x-ray photon correlation spectroscopy in ultra-small angle x-ray scattering geometry. With an increase in the salt concentration, we observe progressive structural and dynamic changes at room temperature, indicating the disruption of yolk components such as yolk-granules and yolk-plasma proteins. Temperature- and salt-dependent structural and dynamic investigations suggest a delay in the gel formation and aggregation of yolk low-density lipoproteins with increasing ionic strength. However, the time-temperature superposition relationship observed in all samples suggests an identical mechanism underlying protein aggregation-gelation with a temperature-dependent reaction rate. The sol-gel transition time extracted from kinetic and dynamic information follows Arrhenius's behavior, and the activation energy (460kJ/mol) is found to be independent of the salt concentration.

X-ray induced long afterglow luminescence from UVC to red region in Ca2P2O7:Pr3+

In this paper, we developed low dose X-ray induced long afterglow phosphor Ca2P2O7:Pr3+, which shows excellent afterglow luminescence from ultraviolet C (UVC) to red region. The photoluminescent results show that under 445.7 nm excitation, Ca1.995P2O7:0.5%Pr3+ displays red emissions peaked at 598.3 and 651.9 nm, corresponding to 1D2-3H4 and 3P0-3F2 transitions of Pr3+, respectively. Due to its pure red emission (CIE coordinates (0.59101,0.39926)), Ca1.995P2O7:0.5%Pr3+ can be regarded as a potential LED red phosphor. More importantly, Ca2P2O7:Pr3+ shows long afterglow luminescence from UVC to red region, which consists of four continuous emissions with similar intensity including 260, 359, 466 and 598.3 nm. Since these afterglow continuous emissions are fitted to the absorption of most photodynamic therapy (PDT) agents, Ca2P2O7:Pr3+ can be regarded as excellent PDT agents. Furthermore, 30 s X-ray irradiation can induce 5400 s decay of Ca1.997P2O7:0.3%Pr3+, and its afterglow emission intensity still reaches 5×104 cps after 5400 s decay. Even only 5 s X-ray irradiation also can produce 4.75×104 cps afterglow emission after 10 s decay. In addition, the repeat 980 nm laser irradiations can induce continuous strong photo-stimulated (PSL) luminescent peaks, which can be utilized to conduct high efficiency PDT without another X-ray irradiation. The thermoluminescence results reveal that the existence of shallow (0.89 eV) and deep traps are responsible for the excellent X-ray induced long afterglow and PSL luminescence. All these results suggest that Ca2P2O7:Pr3+ possesses great potential to be regarded as high efficiency PDT agents.

Early and Late Effects of Low-Dose X-ray Exposure in Human Fibroblasts: DNA Repair Foci, Proliferation, Autophagy, and Senescence.

The effects of low-dose radiation exposure remain a controversial topic in radiation biology. This study compares early (0.5, 4, 24, 48, and 72 h) and late (5, 10, and 15 cell passages) post-irradiation changes in γH2AX, 53BP1, pATM, and p-p53 (Ser-15) foci, proliferation, autophagy, and senescence in primary fibroblasts exposed to 100 and 2000 mGy X-ray radiation. The results show that exposure to 100 mGy significantly increased γH2AX, 53BP1, and pATM foci only at 0.5 and 4 h post irradiation. There were no changes in p-p53 (Ser-15) foci, proliferation, autophagy, or senescence up to 15 passages post irradiation at the low dose.

Bottom-up construction of low-dimensional perovskite thick films for high-performance X-ray detection and imaging

Quasi-two-dimensional (Q-2D) perovskite exhibits exceptional photoelectric properties and demonstrates reduced ion migration compared to 3D perovskite, making it a promising material for the fabrication of highly sensitive and stable X-ray detectors. However, achieving high-quality perovskite films with sufficient thickness for efficient X-ray absorption remains challenging. Herein, we present a novel approach to regulate the growth of Q-2D perovskite crystals in a mixed atmosphere comprising methylamine (CH3NH2, MA) and ammonia (NH3), resulting in the successful fabrication of high-quality films with a thickness of hundreds of micrometers. Subsequently, we build a heterojunction X-ray detector by incorporating the perovskite layer with titanium dioxide (TiO2). The precise regulation of perovskite crystal growth and the meticulous design of the device structure synergistically enhance the resistivity and carrier transport properties of the X-ray detector, resulting in an ultrahigh sensitivity (29721.4 μC Gyair−1 cm−2) for low-dimensional perovskite X-ray detectors and a low detection limit of 20.9 nGyair s−1. We have further demonstrated a flat panel X-ray imager (FPXI) showing a high spatial resolution of 3.6 lp mm−1 and outstanding X-ray imaging capability under low X-ray doses. This work presents an effective methodology for achieving high-performance Q-2D perovskite FPXIs that holds great promise for various applications in imaging technology.

Developing a novel radiosensitive metal ion-loaded PVA/NBT film as medical low-dose X-ray dosimeter

The hazards associated with ionizing radiation exposure has spurred the advancement of reliable and precise dosimetry techniques. Currently, there still lacks a viable and efficient dosimetry methods for measuring radiation expo-sure within low dosage ranges. This raises a concern in certain domains, such as radiodiagnostics and practitioners that employ low-dose X-ray radiation. Hence, this study aims to produce PVA/NBT film dosimeters that are capable in effectively detecting low dosages of X-ray radiation. Moreover, PVA/NBT films loaded by various metal ions will also be studied. The films were synthesized by the solvent casting method. The films were subjected to X-ray irradiation with a dosage ranging from 0 to 2.626 mGy. The films were further examined through EDX analysis, UV–Vis spectroscopy, optical density measurement, FTIR spectroscopy, and SEM analysis. It was observed that X-ray radiation exposure caused a broadening in the UV–Vis absorbance spectrum, which enhances its light absorption capability and making it more opaque. Furthermore, the careful selection of metal ion enhanced the film's ability in detecting X-ray radiation. Silver-loaded films were proven to significantly enhance the linearity and sensitivity of the PVA/NBT dosimeter film. These findings showed that silver-loaded PVA/NBT films exhibit a promising prospect for further applications in the domain of medical radiation.