Low-dose X-ray Research Articles

Radiation dosimetry performance appraisal of the optimal concentration of nitro blue tetrazolium dye in PVA composite film at low X-ray doses.

Due to the extensive use of radiation in various fields, such as food safety, sterilizing surgical materials, and medical diagnostics, it is essential to minimize radiation exposure for both patients and healthcare professionals, even at low doses. To meet this requirement, a composite film has been developed using polyvinyl alcohol (PVA) polymer and nitro blue tetrazolium (NBT) dye to measure low radiation doses effectively. Various concentrations of NBT dye (ranging from 0.75 to 15g/L) were tested to determine the optimal concentration for maximum efficiency. The films were exposed to low doses of X-rays ranging from 20 to 100mGy. The PVA/NBT films exhibited good stability for 30 days after irradiation when stored in darkness. UV-visible absorption spectra showed a peak at 376nm, shifting to 384nm after exposure to X-rays. Furthermore, the response curve based on UV-Vis absorptions revealed a linear increase in absorbance with increased radiation doses up to 60mGy(R=0.99). XRD analysis indicated significant structural rearrangements in films with higher NBT concentrations and radiation doses. Specifically, X-ray irradiation caused two distinct peaks to shift from 2θ=20.12° and 40.18° to 2θ=19.66° and 41.24°. SEM analysis revealed that exposure to increased radiation doses resulted in significant morphological changes in PVA/NBT films, resembling torn tree trunks, especially with higher NBT concentrations. The preparation method was validated by XRF analysis, and the solubility of the NBT salt was excellent, with an R2 value of 0.9656. Results from Spectro colorimetric studies indicated that different CIEL∗a∗b∗ coordinates, as well as the total color difference (ΔE∗ab) and color strength (K/S), were directly proportional to the applied dose intensity, correlating with increasing NBT concentration. The PVA/NBT dosimeter containing 10g/L of NBT shows promising potential as an effective alternative for the prompt and accurate detection of low X-ray doses in diagnostic radiology.

Capillary Force-Assisted CsPbBr3-xIx (x = 0, 1) Columnar Crystal Film for X-ray Detectors with Ultrahigh Electric Field and Sensitivity.

Inorganic halide perovskite thin-film X-ray detectors have attracted great research interest in recent years due to their high sensitivity, low detection limit, and facile fabrication process. The poor crystal quality of the thin film with uncontrollable thickness and low background voltage during detection limits its practical application. Here, a high-quality CsPbBr3-xIx (x = 0, 1) columnar crystal film is prepared by an improved melt-confined method with a porous anodic aluminum oxide (AAO) template, which stabilizes the disorder perovskite systems of CsPbBr2I by stress. The AAO-CsPbBr3-xIx (x = 0) detectors exhibit high detection accuracy and photoelectric conversion capability with an ultrahigh sensitivity of 32,399.5 μC·Gyair-1·cm-2 at 2142.9 V mm-1 under 20 kVp X-rays and 19,217.4 μC·Gyair-1·cm-2 with a higher background electric field of 6666.7 V mm-1 for AAO-CsPbBr3-xIx (x = 1). Moreover, the AAO-CsPbBr3-xIx (x = 1) film detector acquires a lower detection limit of 7.65 nGy·s-1 and a higher X-ray imaging spatial resolution of 1.6 LP/mm and 8.6 nGy·s-1 and 1.4 LP/mm for AAO-CsPbBr3-xIx (x = 0). The facile, high-quality columnar crystal film devices display great potential for low-energy and low-dose X-ray imaging in flat panel detection applications.

Dual Porphyrin-Loaded Scintillating Nanoparticles Enhanced Photodynamic Therapy in Hypoxic Cancer Cells under X-ray Irradiation.

Tumor hypoxia represents a major challenge to achieving successful therapy outcomes with photodynamic therapy (PDT). We hypothesized that systemic loading of dual porphyrins, protoporphyrin IX (PPIX) as a photosensitizer (PS) and hemin (Fe3+-PPIX) as an oxygen generator, onto Eu-doped NaYF4 scintillator (Sc), collectively terms as Eu-PPIX@Hemin, could enhance the activity of X-ray mediated PDT. Catalase-like property of hemin in the presence of H2O2 facilitated the production of oxygen molecules (3O2) in hypoxic cancer cells. The produced 3O2 reacts with nearby excited PPIX molecules (PPIX*) in the Sc-PS pairs to produce singlet oxygen (1O2), as cytotoxic reactive oxygen species (ROS) under X-ray irradiation. Eu-PPIX@Hemin nanoparticles (NPs) with a diameter of ~60 nm efficiently produced oxygen in the presence of H2O2, which its concentration in tumor cells is higher than that in normal cells. Eu-PPIX@Hemin generated similar amounts of ROS in hypoxic cultured cancer cells under low dose X-ray irradiation (0.5 Gy), compared to those in normoxic cancer cells. Notably, Eu-PPIX@Hemin exhibited similar cytotoxic effects in both hypoxic and normoxic cancer cells under X-ray irradiation. Overall, the mutual Sc-PS performance between PPIX and Eu was synergistically enhanced by hemin in Eu-PPIX@Hemin, which relieved hypoxia in the cancer cells under X-ray irradiation.

Optical Properties and Application Development of Glass-Ceramics

Due to the excellent optical properties, glass ceramics are widely used in LED lighting, optical information storage, and other fields. However, the nucleation and growth process of nanocrystals in amorphous glass media is still unclear as to the key to the subjective control of optical properties and its application development. Herein, we propose a real-time in situ TEM imaging method to study the nanocrystal nucleation growth kinetics in amorphous glass media. The results reveal the missing mystery of the nucleation kinetics of amorphous nanoclusters. By directly observing the crystallization process of nanocrystals, the coexistence of the non-classical nucleation theory and the classical nucleation theory was confirmed, and the subjective regulation of the optical properties of glass-ceramics was realized. Based on the excellent optical properties of the optimized glass-ceramic, its application in up-conversion laser, laser refrigeration, short-wave shielding, and other fields has been further realized. Quantum dots with excellent scintillation performance are embedded in the glass to obtain a transparent and uniform composite material. The three-dimensional network structure of the glass ensures its scintillation performance while giving it excellent physical and chemical stability, realizing low-dose high-resolution X-ray imaging, and realizing Repairable after high-dose radiation damage. A trap center and an efficient luminescence center are constructed in the glass to realize mechanoluminescence, and the passive self-driven fiber stress sensing is realized by coupling the optical waveguide effect of the highly transparent glass fiber.

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.

Pure organic phosphorescent scintillator for glucose metabolism regulation-enhanced low-dose X-ray-induced photodynamic therapy

X-ray-induced photodynamic therapy (X-PDT) leverages the penetration power of X-rays to generate reactive oxygen species (ROS) within deep tissues for cancer treatment, merging the benefits of both photodynamic therapy and radiotherapy. Traditional X-PDT, however, typically relies on inorganic scintillators containing heavy-metals to act as energy transducers, exciting nearby photosensitizers to produce singlet oxygen. Moreover, the hypoxia conditions prevalent in tumors can severely diminish the efficacy of X-PDT. Here, we report a metal-free, self-enhanced organic phosphorescent nanoscintillator (termed OPSG NPs) capable of efficiently generating singlet oxygen under low-dose X-ray irradiation, facilitated by glucose metabolism regulation. OPSG NPs are constructed through a self-assembly behavior driven by molecular interactions between an organic phosphorescent scintillator and a glucose transporter 1 (GLUT1) inhibitor. The OPSG NPs serve dual functions, acting as both scintillator and photosensitizer, which can be activated by direct X-ray irradiation. Additionally, they possess the ability to inhibit glucose supply and reduce oxygen consumption for tumor cell respiration. This strategy effectively alleviates the hypoxia within the tumor microenvironment and consequently enhances the therapeutic efficacy of X-PDT. Both in vitro and in vivo studies demonstrate the excellent antitumor X-PDT performance. This glucose metabolism regulation-enhanced low-dose X-PDT strategy paves the way for more efficient therapy against deep-seated tumors.

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.

Thigh and paraspinal muscles change after fusionless bipolar fixation for early onset scoliosis in type 2 spinal muscular atrophy: Modifications in the spinal and thigh muscles of subjects with SMA2 and early onset scoliosis

BackgroundSpinal muscular atrophy is a severe, progressive autosomal recessive neuromuscular disorder associated with neuromuscular scoliosis. When bracing is not sufficient to control the deformity, early spinal surgery is required. To the best of our knowledge, no work in the literature have assessed modifications in spinal and thigh muscles of subjects with type 2 spinal muscular atrophy (SMA2) following spinal surgery. ObjectiveThis study aimed to better understand modifications in the spinal and thigh muscles of subjects with SMA2 and early onset scoliosis, before and after minimally invasive fusionless surgery. Methods and settings20 SMA2 patients with confirmed scoliosis on bi-planar low-dose X-ray were included: 10 preoperative and 10 postoperative patients with a minimal follow-up of 5 years after surgery. The surgery consisted of a bilateral sliding rod construct extended from T1 to the sacrum, through a minimally invasive approach. All subjects had fat/water separation muscle magnetic resonance imaging from the spine to the thigh. The percentage of fat degeneration was compared before and after surgery. A quality-of-life survey was performed. ResultsFat infiltration was diffuse and symmetric in both groups of patients, and on average six times more compared to control subjects previously published at thigh level. Adductors, sartorius, and gracilis were less affected with respectively, 51%, 56%, and 57% of fat fraction before surgery. Comparing the preoperative and postoperative groups, fat infiltration was higher in sartorius and multifidus after surgery (p < 0.05). No significant difference was found for the other muscles studied. These results did not affect quality of life. ConclusionThis is the first study to compare fat infiltration of spinal and thigh muscles of SMA2 patients before and after minimally invasive surgery. Our results demonstrate that muscles were globally preserved apart from multifidus and sartorius which were more affected.

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.

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

C. vulgaris is a microalga with great potential as a source of lipids and essential fatty acids for human nutrition during extended space missions to Mars. However, the effects of Mars-like radiation on lipid composition are still poorly understood. In this study, we analyzed the effects of X-rays on the growth and lipid biosynthesis of C. vulgaris CCALA 269, exposing the cultures to doses of 450, 900, 1800, 3600, and 10,800 mSv, simulating approximately 354, 709, 1417, 2835, and 8504 days of exposure to Martian radiation, respectively. The results show that, although growth remained stable, doses exceeding 1800 mSv led to an increased production of specific lipid classes, suggesting an adaptive mechanism to counteract radiation stress. This adaptation was accompanied by an increase in reactive oxygen species (ROS) and changes in pigment composition, with an elevation in pheophytin-a and chlorophyll-a, and a decrease in chlorophyll-b. Our results demonstrate the ability of C. vulgaris to adapt to ionizing radiation, highlighting its suitability for sustainable lipid production in extraterrestrial environments, supporting human life on Mars through in situ resource utilization.

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.

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.

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.