Radiation Dose Reduction Research Articles

Development and validation of an automated Tomotherapy planning method for cervical cancer

PurposeThis study aimed to develop an automated Tomotherapy (TOMO) planning method for cervical cancer treatment, and to validate its feasibility and effectiveness.Materials and methodsThe study enrolled 30 cervical cancer patients treated with TOMO at our center. Utilizing scripting and Python environment within the RayStation (RaySearch Labs, Sweden) treatment planning system (TPS), we developed automated planning methods for TOMO and volumetric modulated arc therapy (VMAT) techniques. The clinical manual TOMO (M-TOMO) plans for the 30 patients were re-optimized using automated planning scripts for both TOMO and VMAT, creating automated TOMO (A-TOMO) and automated VMAT (A-VMAT) plans. We compared A-TOMO with M-TOMO and A-VMAT plans. The primary evaluated relevant dosimetric parameters and treatment plan efficiency were assessed using the two-sided Wilcoxon signed-rank test for statistical analysis, with a P-value < 0.05 indicating statistical significance.ResultsA-TOMO plans maintained similar target dose uniformity compared to M-TOMO plans, with improvements in target conformity and faster dose drop-off outside the target, and demonstrated significant statistical differences (P+ < 0.01). A-TOMO plans also significantly outperformed M-TOMO plans in reducing V50Gy, V40Gy and Dmean for the bladder and rectum, as well as Dmean for the bowel bag, femoral heads, and kidneys (all P+ < 0.05). Additionally, A-TOMO plans demonstrated better consistency in plan quality. Furthermore, the quality of A-TOMO plans was comparable to or superior than A-VMAT plans. In terms of efficiency, A-TOMO significantly reduced the time required for treatment planning to approximately 20 min.ConclusionWe have successfully developed an A-TOMO planning method for cervical cancer. Compared to M-TOMO plans, A-TOMO plans improved target conformity and reduced radiation dose to OARs. Additionally, the quality of A-TOMO plans was on par with or surpasses that of A-VMAT plans. The A-TOMO planning method significantly improved the efficiency of treatment planning.

DdeNet: A dual-domain end-to-end network combining Pale-Transformer and Laplacian convolution for sparse view CT reconstruction

Sparse view (SV) computed tomography (CT) is a clinical diagnostic technique aimed at reducing radiation dose to the human body from X-rays. However, SVCT reconstructed using conventional filtered back-projection (FBP) algorithms will produce severe streak artifacts. In recent years, convolutional neural networks (CNNs) have demonstrated considerable success in addressing the inverse problem of SVCT reconstruction. However, the local convolutional operations of CNNs ignores long-range dependencies of contextual feature information, thereby limiting their capability in feature extraction. To address this limitation, we propose a dual-domain end-to-end network (DdeNet) combining Pale-Transformer and Laplacian convolution for SVCT reconstruction. Initially, in the projection domain, a UNet is employed to restore the interpolated sinogram. Subsequently, in the image domain, we introduce Pale-Transformer and Laplacian convolution to design a dual-stream feature fusion network for finely restoring the CT images reconstructed by FBP. The dual-stream feature fusion network comprises an image restoration network (IRN) module and an edge enhancement network (EEN) module. The depthwise separable convolution based modified pale-shaped self-attention mechanism in Pale-Transformer captures global feature information of the CT image in the IRN, while the Laplacian convolution and multi-scale convolution block with a squeeze and excitation mechanism in the EEN further extract and restore edge feature information of the CT image. Finally, the feature information output from IRN and EEN is fused along the channel dimension and then convolved to obtain the final reconstructed CT image. Experimental results demonstrate that DdeNet exhibits superior generalization and reconstruction performance compared to the previous CNN or Transformer-based reconstruction methods.

Dose robustness of deep learning models for anatomic segmentation of computed tomography images.

The trend towards lower radiation doses and advances in computed tomography (CT) reconstruction may impair the operation of pretrained segmentation models, giving rise to the problem of estimating the dose robustness of existing segmentation models. Previous studies addressing the issue suffer either from a lack of registered low- and full-dose CT images or from simplified simulations. We employed raw data from full-dose acquisitions to simulate low-dose CT scans, avoiding the need to rescan a patient. The accuracy of the simulation is validated using a real CT scan of a phantom. We consider down to 20% reduction of radiation dose, for which we measure deviations of several pretrained segmentation models from the full-dose prediction. In addition, compatibility with existing denoising methods is considered. The results reveal the surprising robustness of the TotalSegmentator approach, showing minimal differences at the pixel level even without denoising. Less robust models show good compatibility with the denoising methods, which help to improve robustness in almost all cases. With denoising based on a convolutional neural network (CNN), the median Dice between low- and full-dose data does not fall below 0.9 (12 for the Hausdorff distance) for all but one model. We observe volatile results for labels with effective radii less than 19mm and improved results for contrasted CT acquisitions. The proposed approach facilitates clinically relevant analysis of dose robustness for human organ segmentation models. The results outline the robustness properties of a diverse set of models. Further studies are needed to identify the robustness of approaches for lesion segmentation and to rank the factors contributing to dose robustness.

RAdiation Dose Attenuation using RADPAD in CATH lab for primary and secondary operators - RADAR-CATH STUDY.

Radiation injury is an important concern for interventional cardiologists and needs to be addressed. RADPAD is a radiation protection drape that has been shown to reduce the radiation exposure of the primary operator (PO). While Indian data on radiation exposure of the PO in the cath lab are scarce, the exposure of the secondary operator (SO) is even less well studied. The aim of this study was to evaluate the efficacy of RADPAD drapes in reducing radiation doses in the cath lab for the primary as well as the secondary operator. A total of 160 patients (40 patients each with single vessel disease [SVD], double vessel disease [DVD] and triple vessel disease [TVD] undergoing coronary angioplasty, and 40 patients undergoing balloon mitral valvuloplasty [BMV]) were randomised in a 1:1 pattern to undergo a procedure with or without the use of RADPAD. For patients with SVD, DVD and TVD undergoing percutaneous coronary intervention (PCI) and those undergoing BMV, the % reduction with the use of RADPAD reduced the PO's received dose (in mrem) by 65%, 54%, 28% and 67%, respectively, as compared to without RADPAD. The % reduction in relative operator exposure for the PO for the 4 groups was 55%, 34%, 18% and 75%, respectively, with the use of RADPAD. The corresponding % reduction for the SO's received dose (in mrem) was 80%, 63%, 33% and 69% and for relative operator exposure was 74%, 46%, 23% and 76% in the 4 groups, respectively. RADPAD significantly reduces the radiation exposure of the primary and secondary operator during prolonged complex PCI and BMV procedures.

Pharyngeal Constrictor-Sparing Salvage Stereotactic Body Radiation Therapy With Tongue-Out for In-Field Recurrence After Definitive Radiation Therapy for Head and Neck Cancer: Guide to Tongue-Out Radiation Therapy

This report details a pharyngeal constrictor muscle (PCM)–sparing stereotactic body radiation therapy (SBRT) using our institutional technique of “tongue-out” radiation therapy (TORT) for treating a local recurrent cancer in the uvula (GTVuvula) in a patient with history of a definitive chemotherapy with radiation therapy (70 Gy with weekly cisplatin) for a locally advanced laryngeal cancer 4 years ago. TORT includes optimizing the patients’ reproducible tongue-out position using readily available medicine cup (30 cc) followed by sculping the thermoplastic mask with tongue-out, and real-time visual monitoring of the tongue position during the computed tomography simulation scan, cone beam computed tomography acquisition, and treatment. Between arcs during volumetric modulated arc therapy, time for tongue relaxation and saliva swallowing can be given to the patient. Without TORT, the patient's GTVuvula abutted the medial aspect of superior PCM (medial-sPCM) and a substantial volume of the previously irradiated superior PCM (sPCM) would have received high radiation dose from this salvage SBRT (32.5 Gy in 5 fractions). Comparing without TORT, the shortest distance between medial-sPCM-to-GTVuvula was increased by 13 mm with TORT, which reduced radiation dose to sPCM in the salvage SBRT plan. The mean dose to sPCM was decreased from 20.5 Gy without TORT to 12.7 Gy with TORT. With TORT, minimal sPCM volumes fell within higher isodose line: volume receiving ≥ 60% prescription dose (V60%Rx), V80%Rx, and V100%Rx to sPCM was, 4.8 versus 0.7 cc (without vs with TORT, respectively), 2.9 versus 0.19 cc, and 1.6 versus 0.04 cc, respectively. Maximum dose (Dmax) to medial-sPCM was 34.6 Gy without TORT versus 22.7 Gy with TORT. These high doses to the sPCM and intrafractional swallowing-related geographic misses of GTVuvula were avoided through the application of TORT in this salvage reirradiation setting. The patient successfully finished salvage SBRT with TORT resulting in no dysphagia or mucositis and maintained complete response at 12 months after treatment.

Evolving Oral Diagnostics: Cone-beam Computed Tomography's (CBCT) Importance in Contemporary Dentistry

Recent improvements in cone-beam computed tomography (CBCT) have transformed maxillofacial imaging, which formerly depended on 2D imaging. This review highlights the benefits of CBCT in many dental specialties, including implant dentistry, endodontics, orthodontics, and temporomandibular joint examination. CBCT provides remarkable diagnostic accuracy while reducing radiation exposure, making it an invaluable tool in the dental practice. Artificial Intelligence and machine learning integration in CBCT technology offers numerous benefits, including automated image analysis, pathology detection, treatment planning, radiation dose reduction, image enhancement, workflow optimization, predictive analytics, personalized treatment plans, tele dentistry, and dental education. AI's role in dentistry is expected to improve diagnostic and therapeutic capacities while optimizing CBCT scans, resulting in better patient care.

HEAL: High-Frequency Enhanced and Attention-Guided Learning Network for Sparse-View CT Reconstruction.

X-ray computed tomography (CT) imaging technology has become an indispensable diagnostic tool in clinical examination. However, it poses a risk of ionizing radiation, making the reduction of radiation dose one of the current research hotspots in CT imaging. Sparse-view imaging, as one of the main methods for reducing radiation dose, has made significant progress in recent years. In particular, sparse-view reconstruction methods based on deep learning have shown promising results. Nevertheless, efficiently recovering image details under ultra-sparse conditions remains a challenge. To address this challenge, this paper proposes a high-frequency enhanced and attention-guided learning Network (HEAL). HEAL includes three optimization strategies to achieve detail enhancement: Firstly, we introduce a dual-domain progressive enhancement module, which leverages fidelity constraints within each domain and consistency constraints across domains to effectively narrow the solution space. Secondly, we incorporate both channel and spatial attention mechanisms to improve the network's feature-scaling process. Finally, we propose a high-frequency component enhancement regularization term that integrates residual learning with direction-weighted total variation, utilizing directional cues to effectively distinguish between noise and textures. The HEAL network is trained, validated and tested under different ultra-sparse configurations of 60 views and 30 views, demonstrating its advantages in reconstruction accuracy and detail enhancement.

Task-based assessment for radiation dose optimization in CT abdominal examinations: A phantom study

Recent advancements in Computed Tomography (CT) imaging technology have significantly enhanced healthcare delivery. However, public concern regarding the safety and health risks associated with increased exposure to ionizing radiation has escalated. In response, this study performs a quantitative analysis comparing the image quality of the standard CT abdomen protocol (P1 protocols) with alternative optimization techniques. Adjustments to standard CT scan parameters, including tube potential (P2 protocols), effective mAs value (P3), and pitch factor (P4, P5, P6 protocols), were made to evaluate the effectiveness of these optimization strategies. A 64-slice CT scanner (Canon, Japan) and a polymethylmethacrylate (PMMA) textural water phantom was utilized in this study. CT dose descriptors, volume weighted CT Dose Index (CTDIvol) and dose-length product (DLP) alongside evaluation parameters such as Hounsfield Unit (HU) number, noise levels, Signal-to-Noise Ratio (SNR), and Contrast-to-Noise Ratio (CNR) were measured and analysed. Furthermore, this research introduced a Figure of Merit (FOM) based on the ratio of image quality parameters (SNR and CNR) to the CTDIvol, establishing a quantitative measure for optimization. A notable reduction in radiation dose—34.85% below the standard protocol (P1)—was observed in protocol P6, attributed to an increased pitch factor. Conversely, increase the effective mAs value has improved SNR and CNR values. The findings reveal that protocols P1 and P2 deliver the highest FOM for soft tissue and fat imaging, respectively. Protocol P1, with its higher attenuation factor, is optimal for abdominal examinations targeting soft tissues. Meanwhile, protocol P2's increase effective mAs value enhances beam intensity, improving CT numbers for fat tissues with their high-density composition. The study also found a strong correlation between FOM based on SNR and CNR values. In conclusion, adjustments to primary CT parameters significantly influence image quality. The FOM serves as an effective tool for measuring the overall performance of image quality, facilitating post-optimization assessment and contributing to the development of safer, more efficient CT imaging protocols.

Dosimetric analysis of six whole-breast irradiation techniques in supine and prone positions

In breast cancer radiation therapy, minimizing radiation-related risks and toxicity is vital for improving life expectancy. Tailoring radiotherapy techniques and treatment positions can reduce radiation doses to normal organs and mitigate treatment-related toxicity. This study entailed a dosimetric comparison of six different external beam whole-breast irradiation techniques in both supine and prone positions. We selected fourteen breast cancer patients, generating six treatment plans in both positions per patient. We assessed target coverage and organs at risk (OAR) doses to evaluate the impact of treatment techniques and positions. Excess absolute risk was calculated to estimate potential secondary cancer risk in the contralateral breast, ipsilateral lung, and contralateral lung. Additionally, we analyzed the distance between the target volume and OARs (heart and ipsilateral lung) while considering the treatment position. The results indicate that prone positioning lowers lung exposure in X-ray radiotherapy. However, particle beam therapies (PBTs) significantly reduce the dose to the heart and ipsilateral lung regardless of the patient’s position. Notably, negligible differences were observed between arc-delivery and static-delivery PBTs in terms of target conformity and OAR sparing. This study provides critical dosimetric evidence to facilitate informed decision-making regarding treatment techniques and positions.

Investigation of the optimal tube voltage kV exposure parameters for general X-ray of dental cone-beam computed tomography: A cephalometric view

This study aims to investigate and optimize the effect of different exposure parameters on the reduction of noise and radiation dose and to find the optimal balance among tube voltage, tube current, and exposure time for the latest-generation cone-beam computed tomography system (CBCT) at Advanced Medical and Dental Institute, Universiti Sains Malaysia, using the dose area product (DAP) meter. The DAP meter was attached to the X-ray detector of the CBCT device to cover the entire irradiated area and then connected to a Raysafe electrometer. The DAP meter was scanned with the following exposure parameter: constant tube voltage of 70 kV with a varying tube current ranging from 5 mA &amp;ndash; 16 mA and then at a constant tube current of 10mA and a varying tube voltage ranging from 60 kV &amp;ndash; 80 kV. For each scanning protocol, the noise was determined. At constant tube voltage and varying tube current, the noise level ranged from 41.99 &amp;ndash; 82.16, while at constant tube current and varying tube voltage, the noise level ranged from 50.66 &amp;ndash; 60.76 with equal exposure time. A 0.09% increase in noise was observed when the tube voltage was varied. Therefore, low noise protocols should consist of a reduction in the tube current setting rather than a reduction in peak voltage (kVp), as this would result in a smaller level of noise and consequently less quality degradation in the image.

Comparing technical success and clinical outcomes of macrocatheter versus microcatheter in genicular artery embolization for knee osteoarthritis

PurposeThe purpose of this study was to evaluate the comparative effectiveness and safety of using macrocatheters versus microcatheters for genicular artery embolization (GAE) in the management of knee osteoarthritis (OA). The primary outcomes were technical success and adverse events during and immediately after the procedure. The secondary outcome was the clinical outcome over the follow-up period. Materials and methodsIn our retrospective analysis, we included 79 patients undergoing GAE for OA. Patients were categorized based on the catheter type used: microcatheter through macrocatheter or directly through macrocatheter. Key parameters, including technical success, adverse events, procedure duration, radiation exposure, and clinical outcomes (VAS and WOMAC scores), were assessed at 1st, 3rd, and 6th-month intervals. ResultsTechnical success stood at 100 % for the microcatheter group, with a slight reduction for the macrocatheter group at 91 % (p = 0.069). Procedure and fluoroscopy durations were significantly shorter in the macrocatheter group (p < 0.001). Additionally, the macrocatheter group demonstrated a marked reduction in radiation dose, with notably decreased air kerma values. Clinical outcomes, including VAS and WOMAC scores at the predefined intervals, revealed no significant disparities between the two cohorts. ConclusionIn GAE procedures utilizing a temporary embolic agent (imipenem/cilastatin), initiating the intervention with a macrocatheter can be deemed cost-effective, safe and advantageous for patients with less complex vascular anatomy, as it significantly reduces procedural and fluoroscopy times, thereby minimizing radiation exposure. Conversely, in patients with intricate vascular pathways, transitioning to a microcatheter enhances technical success.

Super-resolution deep-learning reconstruction for cardiac CT: impact of radiation dose and focal spot size on task-based image quality.

This study aimed to evaluate the impact of radiation dose and focal spot size on the image quality of super-resolution deep-learning reconstruction (SR-DLR) in comparison with iterative reconstruction (IR) and normal-resolution DLR (NR-DLR) algorithms for cardiac CT. Catphan-700 phantom was scanned on a 320-row scanner at six radiation doses (small and large focal spots at 1.4-4.3 and 5.8-8.8mGy, respectively). Images were reconstructed using hybrid-IR, model-based-IR, NR-DLR, and SR-DLR algorithms. Noise properties were evaluated through plotting noise power spectrum (NPS). Spatial resolution was quantified with task-based transfer function (TTF); Polystyrene, Delrin, and Bone-50% inserts were used for low-, intermediate, and high-contrast spatial resolution. The detectability index (d') was calculated. Image noise, noise texture, edge sharpness of low- and intermediate-contrast objects, delineation of fine high-contrast objects, and overall quality of four reconstructions were visually ranked. Results indicated that among four reconstructions, SR-DLR yielded the lowest noise magnitude and NPS peak, as well as the highest average NPS frequency, TTF50%, d' values, and visual rank at each radiation dose. For all reconstructions, the intermediate- to high-contrast spatial resolution was maximized at 4.3mGy, while the lowest noise magnitude and highest d' were attained at 8.8mGy. SR-DLR at 4.3mGy exhibited superior noise performance, intermediate- to high-contrast spatial resolution, d' values, and visual rank compared to the other reconstructions at 8.8mGy. Therefore, SR-DLR may yield superior diagnostic image quality and facilitate radiation dose reduction compared to the other reconstructions, particularly when combined with small focal spot scanning.

Advancements in Dental Imaging: A Technological Renaissance in Diagnosis and Treatment Planning

Dental imaging technology has undergone significant advancements in recent years, offering dentists unprecedented tools for accurate diagnosis and treatment planning. This article provides a comprehensive overview of the latest innovations in dental imaging and their clinical applications. Cone Beam Computed Tomography (CBCT) has revolutionized imaging by providing high-resolution 3D images with minimal radiation exposure. Its versatility in applications, from implant planning to TMJ analysis, makes it an indispensable tool in modern dentistry. Studies have shown its effectiveness in detecting root fractures and periapical lesions, enhancing diagnostic precision. Digital Radiography has replaced traditional film-based systems, offering benefits like reduced radiation doses and faster image acquisition. Its superior diagnostic capabilities in detecting caries and periodontal conditions enable early intervention and preventive strategies, improving patient outcomes. Intraoral Scanners have transformed impression-taking, eliminating the need for messy materials and improving patient comfort. Their accuracy in capturing detailed intraoral structures ensures precise fit and aesthetics in crown and bridge restorations, enhancing overall treatment quality. Optical Coherence Tomography (OCT) has gained attention for its non-invasive, high-resolution imaging of dental tissues. Its utility in detecting early caries lesions, evaluating periodontal tissues, and assessing adhesive interfaces in restorations supports conservative treatment approaches and long-term restoration success. Artificial Intelligence (AI) algorithms are being integrated into dental imaging, enhancing diagnostic capabilities and streamlining workflow. AI’s role in image analysis, risk assessment, and treatment planning opens avenues for personalized dentistry and predictive outcomes, ultimately improving patient care. In conclusion, the rapid advancements in dental imaging technologies have transformed dental diagnostics and treatment planning. Integrating these innovations into clinical practice not only improves diagnostic accuracy and treatment outcomes but also enhances patient experience and satisfaction. Continued research and technological advancements promise further enhancements in dental imaging capabilities, paving the way for optimized patient care in the future.

Photon-Counting Computed Tomography for Microstructural Imaging of Bone and Joints.

Recently, photon-counting computed tomography (PCCT) has been introduced in clinical research and diagnostics. This review describes the technological advances and provides an overview of recent applications with a focus on imaging of bone. PCCT is a full-body scanner with short scanning times that provides better spatial and spectral resolution than conventional energy-integrating-detector CT (EID-CT), along with an up to 50% reduced radiation dose. It can be used to quantify bone mineral density, to perform bone microstructural analyses and to assess cartilage quality with adequate precision and accuracy. Using a virtual monoenergetic image reconstruction, metal artefacts can be greatly reduced when imaging bone-implant interfaces. Current PCCT systems do not allow spectral imaging in ultra-high-resolution (UHR) mode. Given its improved resolution, reduced noise and spectral imaging capabilities PCCT has diagnostic capacities in both qualitative and quantitative imaging that outperform those of conventional CT. Clinical use in monitoring bone health has already been demonstrated. The full potential of PCCT systems will be unlocked when UHR spectral imaging becomes available.

A multicentre survey of knowledge and implementation of radiation protection techniques in cardiac cath-lab medical personnel

BackgroundAwareness of radiation hazards and methods to reduce radiation dose is a sine qua non for all staff working in the cath-lab for their own safety and their patient’s safety.ResultsThere were large variations in the implementation of radiation protection techniques with overall inadequate radiation risk knowledge. Some members of the cath-lab team are at higher risk of radiation-induced side effects, including the fellows, nurses, technicians, and anaesthesiologists because they spent longer time in the cath-lab and/or their position in relation to the source of radiation. About 10% of the participants have reported different health problems potentially induced by radiation exposure.ConclusionsThere is lack of radiation risks knowledge with inadequate radiation protection practice among cath-lab team. Some members such as fellows, nurse, technicians, and cardiac anaesthesiologist are at higher risks. They represent the forgotten members of the Cath-Lab team.

Intraindividual Comparison of Dose Reduction and Coronary Calcium Scoring Accuracy Using Kilovolt-independent and Tin Filtration CT Protocols.

Purpose To investigate the ability of kilovolt-independent (hereafter, kV-independent) and tin filter spectral shaping to accurately quantify the coronary artery calcium score (CACS) and radiation dose reductions compared with the standard 120-kV CT protocol. Materials and Methods This prospective, blinded reader study included 201 participants (mean age, 60 years ± 9.8 [SD]; 119 female, 82 male) who underwent standard 120-kV CT and additional kV-independent and tin filter research CT scans from October 2020 to July 2021. Scans were reconstructed using a Qr36f kernel for standard scans and an Sa36f kernel for research scans simulating artificial 120-kV images. CACS, risk categorization, and radiation doses were compared by analyzing data with analysis of variance, Kruskal-Wallis test, Mann-Whitney test, Bland-Altman analysis, Pearson correlations, and κ analysis for agreement. Results There was no evidence of differences in CACS across standard 120-kV, kV-independent, and tin filter scans, with median CACS values of 1 (IQR, 0-48), 0.6 (IQR, 0-58), and 0 (IQR, 0-51), respectively (P = .85). Compared with standard 120-kV scans, kV-independent and tin filter scans showed excellent correlation in CACS values (r = 0.993 and r = 0.999, respectively), with high agreement in CACS risk categorization (κ = 0.95 and κ = 0.93, respectively). Standard 120-kV scans had a mean radiation dose of 2.09 mSv ± 0.84, while kV-independent and tin filter scans reduced it to 1.21 mSv ± 0.85 and 0.26 mSv ± 0.11, cutting doses by 42% and 87%, respectively (P < .001). Conclusion The kV-independent and tin filter research CT acquisition techniques showed excellent agreement and high accuracy in CACS estimation compared with standard 120-kV scans, with large reductions in radiation dose. Keywords: CT, Cardiac, Coronary Arteries, Radiation Safety, Coronary Artery Calcium Score, Radiation Dose Reduction, Low-Dose CT Scan, Tin Filter, kV-Independent Supplemental material is available for this article. © RSNA, 2024.

Mitochondrial Targeted Cerium Oxide Nanoclusters for Radiation Protection and Promoting Hematopoiesis.

Mitochondrial oxidative stress is an important factor in cell apoptosis. Cerium oxide nanomaterials show great potential for scavenging free radicals and simulating superoxide dismutase (SOD) and catalase (CAT) activities. To solve the problem of poor targeting of cerium oxide nanomaterials, we designed albumin-cerium oxide nanoclusters (TPP-PCNLs) that target the modification of mitochondria with triphenyl phosphate (TPP). TPP-PCNLs are expected to simulate the activity of superoxide dismutase, continuously remove reactive oxygen species, and play a lasting role in radiation protection. First, cerium dioxide nanoclusters (CNLs), polyethylene glycol cerium dioxide nanoclusters (PCNLs), and TPP-PCNLs were characterized in terms of their morphology and size, ultraviolet spectrum, dispersion stability and cellular uptake, and colocalization Subsequently, the anti-radiation effects of TPP-PCNLs were investigated using in vitro and in vivo experiments including cell viability, apoptosis, comet assays, histopathology, and dose reduction factor (DRF). TPP-PCNLs exhibited good stability and biocompatibility. In vitro experiments indicated that TPP-PCNLs could not only target mitochondria excellently but also regulate reactive oxygen species (ROS)levels in whole cells. More importantly, TPP-PCNLs improved the integrity and functionality of mitochondria in irradiated L-02 cells, thereby indirectly eliminating the continuous damage to nuclear DNA caused by mitochondrial oxidative stress. TPP-PCNLs are mainly targeted to the liver, spleen, and other extramedullary hematopoietic organs with a radiation dose reduction factor of 1.30. In vivo experiments showed that TPP-PCNLs effectively improved the survival rate, weight change, hematopoietic function of irradiated animals. Western blot experiments have confirmed that TPP-PCNLs play a role in radiation protection by regulating the mitochondrial apoptotic pathway. TPP-PCNLs play a radiologically protective role by targeting extramedullary hematopoietic organ-liver cells and mitochondria to continuously clear ROS.

73‐2: Ultrasensitive Image Sensor Based on Amorphous Silicon Avalanche Photodiodes (a‐Si APD) Used for Optical Fingerprint Identification and Flat‐panel X‐ray Detector

The amorphous avalanche photodiodes (a‐Si APD) have been first introduced into flat‐panel detector. The sensor with a‐Si APD indicate much higher sensitivity than normal PIN PD devices. The ultrasensitive image sensor with a‐Si APD can realize optical fingerprint identification under COE OLED screen with very low transmittance. And the flat‐panel X‐ray detector (FPXD) with a‐Si APD can reduce radiation dose significantly because of its much higher sensitivity compared to traditional FPXD products.

Diagnostic reference levels in spinal CT: Jordanian assessments and global benchmarks.

To reduce radiation dose and subsequent risks, several legislative documents in different countries describe the need for Diagnostic Reference Levels (DRLs). Spinal radiography is a common and high-dose examination. Therefore, the aim of this work was to establish the DRL for Computed Tomography (CT) examinations of the spine in healthcare institutions across Jordan. Data was retrieved from the picture archiving and communications system (PACS), which included the CT Dose Index (CTDI(vol)) and Dose Length Product (DLP). The median radiation dose values of the dosimetric indices were calculated for each site. DRL values were defined as the 75th percentile distribution of the median CTDI(vol) and DLP values. Data was collected from 659 CT examinations (316 cervical spine and 343 lumbar-sacral spine). Of the participants, 68% were males, and the patients' mean weight was 69.7 kg (minimum = 60; maximum = 80, SD = 8.9). The 75th percentile for the DLP of cervical and LS-spine CT scans in Jordan were 565.2 and 967.7 mGy.cm, respectively. This research demonstrates a wide range of variability in CTDI(vol) and DLP values for spinal CT examinations; these variations were associated with the acquisition protocol and highlight the need to optimize radiation dose in spinal CT examinations.

Intraoperative Ionizing Radiation Exposure Awareness and Associated Morbidity in Neurosurgery: A Nationwide Survey

Neurosurgeons often use radiation to visualize blood vessels and implants intraoperatively. However, high exposure to radiation increases one's cancer risk. This study aims to investigate intraoperative ionizing radiation exposure awareness and associated morbidity among neurosurgeons. An anonymized 30-question survey about their intraoperative radiation exposure, protective measures, radiation knowledge, and any conditions that can arise from protracted radiation exposure was disseminated to 3344 American Association of Neurological Surgeons members. A total of 227 (6.8%) neurosurgeons completed the survey. Most neurosurgeons (61, 27%) performed 2-4 surgeries per week necessitating radiation (61, 27%), did not use a dosimeter (134, 59%), and wore a lead apron (89%) and a thyroid shield (75%). Only 7 (3%) of respondents could correctly identify the safety limit for occupational radiation. One hundred and thirty-four (59%) respondents correctly identified the relationship between distance and radiation dose reduction. Two hundred and thirteen (94%) neurosurgeons reported concern about occupational radiation exposure. No significant association was found between occupational radiation exposure and the rate of cataracts, combined cancer, and skin cancer. Multivariate logistic regression adjusting for age and cancer history found that the likelihood of developing leukemia (P= 0.02) and nonmalignant thyroid nodular disease (P= 0.01) is positively associated with increased total occupational radiation exposure. There is a need for improved radiation safety awareness among neurosurgeons, especially in the context of rising usage of minimally invasive surgery. This can allow for a greater understanding of radiation-associated risks among neurosurgeons and guide the implementation of safer practices.