Suphalak Khamruang Marshall

Lead-free polymer composites are being developed to reduce occupational radiation exposure associated with nuclear medicine procedures. This study fabricated monolithic and four-layer hybrid Bi₂O₃/WO₃ nanoparticle-filled diglycidyl ether of bisphenol A epoxy composites for attenuating the 140.5-keV photons emitted by technetium-99m (^99mTc). Bi- and W-containing powders were prepared by wet-chemical precipitation and incorporated into the epoxy matrix at 25 and 50 parts per hundred parts of resin. Alternating B50/W50/B50/W50 (ML-BW50) and reverse-layer configurations were produced by sequential casting with a total specimen thickness of 2.0 cm. The nanoparticle dispersions and cured composites were evaluated using DLS, zeta-potential analysis, FE-SEM–EDX, XRD, FTIR spectroscopy, PBS contact-angle measurements, and supplementary tensile testing. Shielding performance was measured at ^99mTc activities of 925 MBq (25 mCi) and 6.105 GBq (165 mCi) using an anthropomorphic thorax phantom and an electronic personal dosimeter under a fixed source–shield–detector geometry. The Bi₂O₃ and WO₃ dispersions exhibited Z-average hydrodynamic diameters of 646.41 and 413.38 nm and zeta potentials of −33.70 and −31.65 mV, respectively. FE-SEM and EDX analyses documented compositionally differentiated Bi-rich and W-rich layers in ML-BW50. XRD identified a mixed-phase Bi- and W-containing filler system, including α-Bi₂O₃, bismuth oxide carbonate hydroxide, WO₃, and residual Na₂WO₄·2H₂O, while FTIR spectra retained the characteristic bands of the cured epoxy network. ML-BW50 exhibited a maximum tensile stress of 4.008 MPa, a terminal strain of 74.294%, and a tensile toughness of 2.250 MJ·m⁻³, representing the highest tensile toughness among the investigated epoxy-based formulations. The shielding formulation significantly affected the background-corrected personal dose equivalent, Hp(10), at both activities (both p < 0.0001), and the multilayer specimens reduced Hp(10) by approximately 45–72% relative to their corresponding monolithic composites. ML-BW50 was the most effective lead-free formulation, producing Hp(10) values of 33.15 ± 2.75 and 228.42 ± 6.50 µSv and radiation-shielding efficiencies of 77.42% and 82.70% at 925 MBq and 6.105 GBq, respectively. ML-BW50 and the 0.5-mm lead reference produced statistically comparable Hp(10) values at 925 MBq, whereas ML-BW50 produced a 9.12% lower Hp(10) than lead at 6.105 GBq. For the same 10 × 10 cm projected area, ML-BW50 had a mass of 44.0 g compared with 77.0 g for lead, representing a 42.9% mass reduction, and exhibited a mean PBS contact angle of approximately 102.3°. Collectively, ML-BW50 combined effective ^99mTc attenuation, reduced specimen mass, differentiated multilayer organization, low PBS wettability, and favorable tensile-energy absorption, supporting its continued development as a lead-free occupational shielding material for nuclear medicine.

Lead-free polymer composites containing high-atomic-number fillers are promising alternatives to conventional lead shielding for nuclear medicine applications. In this study, Bi₂O₃-, WO₃-, and hybrid Bi₂O₃/WO₃ nanoparticle-filled epoxy resin composites were fabricated and evaluated for attenuation of the 140 keV photons emitted by technetium-99m (Tc-99m). The synthesized Bi₂O₃ and WO₃ nanoparticles exhibited hydrodynamic diameters of 638.2 ± 11.3 and 404.2 ± 3.2 nm, respectively, with polydispersity indices below 0.30 and zeta potentials of −33.73 ± 0.63 and −32.47 ± 0.75 mV, indicating acceptable dispersion characteristics and colloidal stability. SEM–EDX confirmed successful incorporation of Bi- and W-containing phases into the epoxy matrix, while the XRD and FTIR analyses verified retention of the crystalline metal oxide phases and the principal chemical structure of the cured epoxy network. Tensile testing revealed a composition-dependent strength–ductility relationship, with the Bi₂O₃-filled composite exhibiting the highest tensile strength among the developed formulations and the hybrid composite showing the greatest elongation at break. XCOM and Phy-X/PSD simulations demonstrated that increasing high-Z filler content enhanced the mass and linear attenuation coefficients and reduced the half-value layer, tenth-value layer, and mean free path. Experimental shielding performance was evaluated using Hp(10) measurements with optically stimulated luminescence dosimeters positioned on an anthropomorphic thorax phantom under a fixed Tc-99m exposure geometry. The transmitted dose decreased with increasing filler loading, and nanoparticle-filled formulations generally outperformed the corresponding conventional-particle composites. The hybrid 75:25 Bi₂O₃/WO₃ NP composite exhibited the lowest mean Hp(10) value of 0.016 µSv, corresponding to a 50% reduction relative to the lead reference under the investigated geometry. The combined structural, mechanical, computational, and dosimetric results demonstrate that hybrid filler design enables simultaneous optimization of attenuation efficiency and mechanical tolerance. These findings identify the Bi-rich hybrid epoxy composite as a promising lead-free material for customized shielding components, including vial holders, syringe-shield housings, protective panels, and workstation accessories used during Tc-99m handling in nuclear medicine.

Background: Radiologic technology (RT) education faces challenges in bridging theory and practice due to limited clinical opportunities. While virtual reality (VR) enables safe and repeatable practice, a systematic instructional design framework is needed to develop scalable, procedure-focused modules. Objective: This study evaluates the Radiologic Technology Virtual Reality (RTVR) framework that integrates 360-degree video capture, instructional overlays, interactive assets, and an immersive content authoring platform to deliver a contrast-enhanced computed tomography (CECT) brain scan module. Methods: In this open-label, parallel-group, randomized controlled trial, 36 year-2 and year-3 RT students with no prior clinical training in diagnostic radiology at a university hospital in Thailand were randomly allocated (1:1) to a VR group or a conventional document-based instruction (control) group. The VR group completed the VR module, a grounded instructional design framework using 360-degree videos and a structured prebrief and debrief, for 20 minutes using a head-mounted display. The control group studied standard curriculum materials for the same duration. Blinding of participants was not possible. Outcome assessment was blinded. The primary outcome was declarative knowledge gain, assessed using a 20-item multiple-choice test before and after intervention. Secondary outcomes included technology acceptance, student satisfaction, and physiological responses during VR immersion. Results: All 36 randomized participants (VR: n=18, control: n=18) completed the study and were included in the analysis. Experts validated the module as suitable and highly appropriate. Students reported high technology acceptance and satisfaction. Both VR and conventional methods produced substantial gains in declarative knowledge. No statistically significant difference in knowledge gain was detected between groups (test × group: unstandardized regression coefficient β=.056, 95% CI −1.360 to 1.473, P =.94). Year-2 students, who had less prior clinical exposure, showed larger pretest to posttest knowledge gains compared to year-3 students. Physiological monitoring showed a reduction in heart rate across the session, while blood pressure remained stable. No adverse events or VR-related discomfort requiring discontinuation was observed. Conclusions: The RTVR framework, which uses a real 360-degree video of authentic clinical settings, offers a scalable approach to procedural VR content creation without requiring specialist technical skills, distinguishing it from prior VR studies in radiography. These findings support the RTVR framework as a feasible, evidence-informed supplement to RT curricula for knowledge-focused procedural teaching, with learning outcomes comparable to those of conventional instruction in this context.

Background: The working environment of nuclear medicine staff is a critical factor in occupational sustainability, particularly in newly established clinical services where safety systems and workflows are still developing. Objectives: This study examined the relationship between quality of work life (QWL), job satisfaction, and occupational radiation exposure among healthcare professionals in a newly established cyclotron and molecular imaging nuclear medicine center equipped with a PET/CT facility that has been operational for less than 5 years. Methods: A mixed-methods design was applied, integrating a cross-sectional assessment of QWL and job satisfaction with environmental radiation monitoring and personal dose mapping associated with ¹⁸ F-FDG procedures. Participants included radiochemists, nurses, radiological technologists, and support staff. Results: Qualitative findings indicated strong theoretical knowledge of radiation protection principles following structured training; however, early-stage operational barriers such as limited access to protective equipment, lack of real-time dosimetry, and workflow pressures often hindered consistent safety compliance. These issues motivated a quantitative evaluation of occupational dose distribution across different body regions. Environmental dose mapping and extremity dosimetry revealed significant variation in exposure among professional groups, with radiochemists demonstrating the highest extremity doses, particularly at the right thumb, index finger, and palm ( p < 0.05), reflecting direct manual handling during radiopharmaceutical synthesis and dispensing. Despite moderate overall job satisfaction, safety training improved radiation safety awareness by approximately 80% and increased adherence to radiation protection protocols from 14.29% to 87%. Conclusion: The findings suggest that while education may enhance radiation safety awareness, early-stage workflow constraints and manual handling tasks may remain important contributors to occupational exposure. These results emphasize the potential importance of integrating accurate dose monitoring, ergonomic workflow design, and continuous education during the early development of nuclear medicine services to help maintain exposures within ALARA limits and support a resilient and sustainable healthcare workforce. Furthermore, the findings indicate that combining objective radiation monitoring with organizational and psychosocial assessment may help inform proactive occupational health planning in newly established nuclear medicine centers.

Antimicrobial resistance is a major global health threat, creating an urgent need for effective non-antibiotic antimicrobial strategies. In this study, CS–AgNPs were synthesized by electron-beam radiolysis, providing a clean, dose-controllable route that avoids additional chemical reducing agents. The effects of irradiation dose and chitosan concentration on nanoparticle formation, physicochemical properties, and antibacterial activity were systematically evaluated. Spectroscopic and structural analyses confirmed the formation of highly crystalline, face-centered cubic silver nanoparticles uniformly dispersed within the chitosan matrix, with Ag–polymer coordination involving –NH₂ and –OH functional groups. Under the optimal conditions (8 kGy, 0.06 mmol AgNO₃, and 0.05% w/v chitosan), ultrasmall, well-dispersed CS–AgNPs were obtained, with an average size of 5.30 ± 2.01 nm and high phase purity. Antibacterial evaluation demonstrated potent, concentration-dependent activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with low minimum inhibitory and minimum bactericidal concentrations (MIC/MBC = 1.96 µg/mL). These findings define a clear structure–property–activity relationship and support a synergistic antibacterial effect between nanosilver and chitosan, while maintaining favorable in vitro cytocompatibility and hemocompatibility within the effective concentration range. Overall, electron-beam radiolysis represents a promising scalable platform for producing broad-spectrum antimicrobial nanomaterials with potential utility in addressing antimicrobial resistance.

Injection-related errors remain a common clinical issue and can cause patient discomfort, hematoma formation, and procedural inefficiencies. The visualization of subcutaneous veins using near-infrared (NIR) imaging has gained attention as an effective approach to reducing such errors, as blood exhibits a higher absorption of NIR light than surrounding tissue. In this study, a low-cost, non-invasive vein visualization system is presented to support safer and more accurate venous access. The proposed system integrates an NIR illumination source and a modified webcam within a compact equipment enclosure, allowing subjects to be conveniently examined by placing their arm inside the device. Vein images are automatically acquired using a laptop-based platform, followed by digital image processing techniques for vein enhancement and visualization. Laboratory-scale experiments were conducted on healthy volunteers to evaluate system performance under multiple conditions, including different vein locations (upper and lower arm regions), varying distances between the NIR light source and the arm (15 cm and 20 cm), and ambient illumination interference (light sources on and off). The experimental results demonstrate the successful implementation and reliable operation of the proposed system. Effective vein visualization was achieved across all test conditions, as confirmed by qualitative visual assessment and quantitative image quality metrics, including the Peak Signal-to-Noise Ratio (PSNR) and Mean Squared Error (MSE). Overall, the proposed system offers a practical, accessible, and cost-effective solution for vein visualization, showing strong potential for clinical and experimental applications aimed at reducing injection errors and improving venous access reliability.

This study employs simulation tools to design and evaluate lightweight, lead-free polymer composites incorporating polytetrafluoroethylene (PTFE), polyethylene (PE), and polyetherimide (PEI) for gamma radiation shielding in nuclear medicine. Targeting clinically relevant photon energies from Tc-99m (140 keV), I-131 (364 keV), and Cs-137 (662 keV), composites’ structural and shielding performance with Bi₂O₃ and WO₃ was assessed using XCOM and Phy-X/PSD. PEI emerged as the most suitable polymer for load-bearing and thermally exposed applications, offering superior mechanical stability and dimensional integrity. Bi₂O₃-WO₃ fillers for Tc-99m achieved a ~7000-fold increase in MAC, I-131 ~2063-fold, and Cs-137 ~1370-fold compared to PbO₂. The PEI-75Bi₂O₃-25WO₃ achieved a ~21-fold reduction in half-value layer (HVL) compared to lead for Tc-99m. For higher-energy isotopes of I-131 and Cs-137, HVL reductions of ~0.44-fold and ~0.08-fold, respectively, were achieved. The results demonstrate that high-Z dual filler polymer composites have an equal or enhanced attenuation properties to lead-based shielding, whilst also enhancing the polymer composites’ mechanical and thermal characteristics. As the use of ionizing radiation increases, so does the potential risks; high-Z dual filler polymer composites provide a sustainable, lightweight, non-toxic alternative to conventional lead shielding.

Tungsten oxide (WO₃) is a high-density material with exceptional radiation attenuation properties, making it a strong candidate for advanced shielding applications. This study explores the structural, mechanical, and shielding performance of WO₃-reinforced polyisoprene composites. Morphological analysis reveals a plate-like structure, indicating robust interfacial interactions that enhance mechanical integrity and thermal stability. X-ray diffraction confirms the crystalline nature of WO₃, while Fourier transform infrared spectroscopy detects distinct W–O bond absorption bands, validating uniform dispersion. Computational analysis using XCOM demonstrates remarkable improvements in attenuation properties, particularly at intermediate- and high-photon energies. While PbO₂ outperforms at lower energies due to the photoelectric effect, Phy-X/PSD analysis confirms that composites with ≥75% WO₃ offer strong shielding capabilities. Variations in effective atomic number, linear attenuation coefficient, and mass attenuation coefficient establish WO₃-reinforced NR as a compelling lead-free alternative, especially for Tc-99m applications. Experimental findings further reveal that increasing WO₃ content significantly reduces Tc-99m gamma radiation dose equivalents Hp(0.07), Hp(3), and Hp(10), emphasizing the potential of WO₃-reinforced composites for next-generation radiation shielding solutions.

This study investigates the development of advanced radiation shielding materials incorporating bismuth oxide (Bi₂O₃) nanoparticles (NPs) into polymethyl methacrylate (PMMA) composites, comparing efficacy against I-131 gamma radiation. The NPs exhibit a 1.53-fold reduction in z-average diameter and a significantly higher surface area than Bi₂O₃, ensuring superior dispersion and structural uniformity within the PMMA matrix. These characteristics, validated through SEM, EDX, and XRD analyses, contribute to enhanced gamma radiation attenuation, leveraging the high atomic number and density of Bi₂O₃. Mechanical evaluations reveal that increasing Bi₂O₃-NPs concentrations enhances ductility but reduces tensile strength, likely due to nanoparticle agglomeration and stress concentration. Radiation shielding performance, assessed using XCOM and Phy-X/PSD simulations, demonstrates a direct correlation between Bi₂O₃ content and attenuation efficiency. Notably, composites with 75% Bi₂O₃ content exhibit attenuation properties comparable to, or exceeding, those of PbO₂, achieving superior shielding efficacy at reduced thicknesses across various photon interaction mechanisms. These findings position Bi₂O₃ NPs-enhanced PMMA composites as promising lightweight high-performance alternatives to lead-based shields. By addressing toxicity and environmental concerns associated with lead, this work emphasizes the potential of high-Z nanomaterials in advancing radiation protection applications. This study highlights a transformative approach to designing safer and more efficient shielding solutions, contributing to the next generation of radiation protection materials.