Total Radiation Dose Research Articles

A Peptide Nanoregulator Enriched at the Endoplasmic Reticulum for Boosting Fractionated Radiotherapy‐Mediated Antitumor Immune Response

AbstractFractionated radiotherapy (FRT), typically delivering low‐dose radiation of 2 Gy per fraction, has been used as the main clinical treatment regimen for various tumors. However, its therapeutic efficacy is severely hindered by inadequate pro‐immunogenic effect and ionizing radiation‐induced immunosuppression. Herein, a peptide nanoregulator (SPER‐NO‐Ind) is constructed from self‐assembling peptides that can enrich nitric oxide (NO) at the endoplasmic reticulum (ER) and inhibit indoleamine 2,3‐dioxygenase (IDO) to enhance FRT‐mediated antitumor immunity and reinforce treatment outcomes. SPER‐NO‐Ind triggered S‐nitrosylation of the ryanodine receptor by ER‐specific enrichment of NO, triggering the release of Ca2+ within ER and induction of robust ER stress. The combination of 2 Gy γ‐radiation with SPER‐NO‐Ind induced intense immunogenic cell death (ICD) in ER‐stressed 4T1 cells. Furthermore, this nanoregulator inhibited IDO and decreased kynurenine production, reversing FRT‐induced immunosuppressive effects. The combined application of FRT and SPER‐NO‐Ind demonstrated superior efficacy in suppressing breast tumor growth, amplifying abscopal effects, and inhibiting metastasis in mice. The SPER‐NO‐Ind treatment achieved a 40% decrease in the total radiation dose while securing equivalent tumor suppression efficacy. Collectively, the work presents a facile approach to augment the efficacy of fractionated radiotherapy for tumors, opening up a new way to enhance the antitumor immune response of radiotherapy.

Skeletal surveys for suspected infant abuse: patient-specific radiation dose estimation using a hybrid computational phantom.

Radiographic skeletal survey plays an important role in the diagnosis of infant abuse. Some practitioners have expressed concerns about the radiation exposure from this examination. To utilize state-of-the-art hybrid computational phantoms to more accurately estimate radiation doses of skeletal surveys performed for suspected infant abuse. We searched our imaging database to identify skeletal surveys performed for suspected infant abuse (5/2020-5/2022). Initial skeletal surveys consisted of 25 standardized radiographs while follow-up skeletal surveys consisted of 16 standardized radiographs (no frontal or lateral views of the skull; or lateral views of the spine, knees, and ankles). To estimate the patient-specific organ and effective dose, we applied the National Cancer Institute dosimetry system for Radiography and Fluoroscopy (with on-the-fly 3D Monte Carlo simulation) to the male and female infant hybrid computational phantoms. The mean total effective radiation dose was 0.627 mSv (initial survey) and 0.495 mSv (follow-up survey). For both surveys, the anteroposterior chest radiograph was the largest contributor to effective dose (contributing 0.101 mSv and 0.108 mSv, respectively). In the initial skeletal survey, the lens and the eyeballs received the highest organ absorbed doses (with the skull radiographs as the major contributors); and in the follow-up skeletal survey, the breasts received the highest organ absorbed dose (with the chest radiographs as the major contributors). We employed hybrid computational phantoms to better estimate the radiation profile of skeletal surveys performed for suspected infant abuse, thus enabling us to update and optimize this life-saving imaging protocol.

Prognostic significance of the mEPE score in intermediate-risk prostate cancer patients undergoing ultrahypofractionated robotic SBRT.

This study aimed to evaluate the prognostic significance of magnetic resonance imaging (MRI) parameters on biochemical failure-free survival (BFS) in patients diagnosed with intermediate-risk prostate cancer and treated with robotic ultrahypofractionated stereotactic body radiotherapy (SBRT) without androgen deprivation therapy (ADT). Aretrospective analysis was conducted in patients with intermediate-risk prostate cancer undergoing robotic SBRT delivered in five fractions with atotal radiation dose of 35-36.25 Gy. The primary endpoint was biochemical failure as defined by the Phoenix criteria. Among other clinicopathological data, Tstage, Prostate Imaging-Reporting and Data System (PI-RADS) score, and multiparametric magnetic resonance imaging-based extra-prostatic extension (mEPE) score were collected and analyzed using the log-rank test. Atotal of 74patients were eligible for analysis. Median age at treatment was 68.8 years and median prostate volume was 47.8cm3. Fifty-four and 14patients were diagnosed with Gleason scores 7a and 7b, respectively. In total, 40patients were classified as having unfavorable intermediate-risk prostate cancer according to American Urological Association/American Society for Radiation Oncology/ Society of Urologic Oncology (AUA/ASTRO/SUO) guidelines. The median follow-up was 30months (range: 4-91.2 months; interquartile range (IQR): 18.5-48months). The 3‑year BFS was 92%. Atotal of 12(16.2%) biochemical failures were reported. In univariate analysis, an mEPE score of 5, the delivered total radiation dose (35 Gy vs. 36.25 Gy), and aprostate-specific antigen (PSA) nadir >1 ng/ml were associated with lower BFS (mEPE-BFS: p < 0.001, total radiation dose-BFS: p = 0.04, PSAnadir-BFS: p =< 0.001). Patients diagnosed with intermediate-risk prostate cancer with ahigh mEPE score are more likely to experience biochemical failure after SBRT. Treatment intensification measures, such as administration of concomitant ADT, should be considered.

Evaluation of machine learning models for predicting xerostomia in adults with head and neck cancer during proton and heavy ion radiotherapy.

Few studies have examined the factors associated with xerostomia during proton and carbon ion radiotherapy for head and neck cancer (HNC), which are reported to have fewer toxic effects compared to traditional photon-based radiotherapy. This study aims to evaluate the performance of machine learning approaches in predicting grade 2 + xerostomia in adults with HNC receiving proton and carbon ion radiotherapy. A retrospective study involving 1,769 adults with HNC who completed proton or carbon ion radiotherapy was conducted. Xerostomia was graded using the Radiation Therapy Oncology Group criteria. Eight machine learning models with different combinations sampling methods and class weights were compared to identify the model with the highest balanced accuracy. The mean age of patients was 47.8 years (range 18-80), with 33.5 % female. The average total radiation dose was 71.0 GyE (SD = 5.7). Grade 1 xerostomia was recorded in 572 patients (32.3 %) and grade 2 in 103 patients (5.8 %). No cases of grade 3 or higher xerostomia were reported. A support vector machine with a linear kernel, a 1:2 positive-to-negative class weight, and SMOTE oversampling achieved the highest balanced accuracy (0.66) and AUC-ROC (0.69) for predicting grade 2 xerostomia, outperforming the logistic regression model (balanced accuracy:0.50, AUC-ROC. 0.67). The prevalence of grade 2 radiation-induced xerostomia during proton and carbon ion radiotherapy was low in adults with HNC, posing challenges for accurate prediction. Further research is needed to develop improved methods for predicting xerostomia during proton and carbon ion radiotherapy.

Common oral conditions associated with post-radiotherapy patients in Africa

Radiotherapy involves the use of high-energy radiation to shrink and or kill cancer cells, thus preventing the cells from growing, dividing, and spreading. Oral conditions associated with radiotherapy can affect the quality of life of post- radiotherapy patients when symptoms are not managed or prevented. The effects of radiotherapy on oral tissues is dependent on the total radiotherapy dose, fractionation system used, radiotherapy volume, radiation techniques used, entire and daily doses of radiotherapy and location of the tumour. Age, poor oral hygiene status prior to radiotherapy, gender, alterations in salivary production, mucosal trauma and nutritional status of the patient are some factors associated with radiotherapy related oral manifestations . After searching PubMed, ScienceDirect, African journal online and Google scholar by two independent investigators. The aim of this article was to review the available studies on the prevalence and common oral conditions/manifestations associated with post-radiotherapy patients in Africa. The oral conditions or manifestations reported from Africa based studies are oral mucositis , xerostomia ,dysphagia, radiation-related dental caries, dermatitis, altered taste sensation and osteoradionecrosis of the mandible. Treatment options for oral mucositis include basic oral care, sodium bicarbonate mouthwash, cryotherapy , chlorhexidine mouthwash, mixed medication mouthwash, anti-inflammatory agents, anti-microbial agents, local anesthetics, analgesics and natural agents such as honey. Xerostomia (dry mouth) can affect speech , taste ,chewing, swallowing and quality of life. There is need for more research towards understanding the preventive and treatment interventions to improve quality of life of post-radiotherapy patients.

Exploration of Optical Fiber and Laser Cutting Head Applications in High-Radiation Environments for Fast Reactor Spent Fuel Reprocessing.

Fast-neutron reactors are an important representative of Generation IV nuclear reactors, and due to the unique structure and material properties of fast reactor fuel, traditional mechanical cutting methods are not applicable. In contrast, laser cutting has emerged as an ideal alternative. However, ensuring the stability of optical fibers and laser cutting heads under high radiation doses, as well as maintaining cutting quality after irradiation, remains a significant technical challenge. Here, we study the performance changes in optical fibers exposed to a total radiation dose of 105 Gy, focusing on power transmission and thermal characteristics. By integrating irradiated optical fibers with irradiated laser cutting heads, simulated cutting experiments on the hexagonal tubes of spent fuel from fast reactors (fast reactor simulation assembly) were conducted. Critical cutting quality parameters, including kerf width, surface roughness, and slagging length, were analyzed. The results indicate that, while the power transmission performance of irradiated optical fibers shows slight degradation, its impact on cutting quality is minimal. High-quality cutting can still be achieved under optimized parameters. This study confirms the feasibility of laser cutting technology in high-radiation environments and provides essential technical support for its application in nuclear fuel reprocessing.

The inhibitory impact of various total body irradiation doses on the hematopoietic system of mice

Irradiation with X-rays has been widely utilized in the clinical treatment of solid tumors and certain hematopoietic malignancies. However, this method fails to completely distinguish between malignant and normal cells. Prolonged or repeated exposure to radiation, whether due to occupational hazards or therapeutical interventions, can cause damage to normal tissues, particularly impacting the hematopoietic system. Therefore, it is important to investigate the effects of total body irradiation on the hematopoietic system of mice and to compare the inhibitory effects of various doses of irradiation on this system. In this study, we primarily employed flow cytometry to analyze mature lineage cells in the peripheral blood, as well as immature hematopoietic stem and progenitor cells (HSPCs) in the bone marrow and spleen. Additionally, we evaluated the multilineage differentiation capacity of HSPCs through colony-forming cell assays. Our results indicated that peripheral B and T cells demonstrated increased sensitivity to irradiation, with significant cell death observed 1-day post-irradiation. Common lymphoid progenitor cells exhibited greater radiotolerance compared to other progenitor cell types, enabling them to maintain a certain population even at elevated doses. Moreover, notable differences were observed between intramedullary and extramedullary hematopoietic stem cells and common lymphoid progenitor cells regarding the extent of damage and recovery rate following irradiation. The multilineage differentiation capacity of HSPCs was also compromised during radiation exposure. In conclusion, different types of mature blood cells, along with immature HSPCs, exhibited varying degrees of sensitivity and tolerance to irradiation, resulting in distinct alterations in cell percentages and numbers.

Discolouration and Chemical Changes of Beech Wood After CO2 Laser Engraving

This study evaluated the influence of infrared laser radiation produced by a CO2 laser, performing under different engraving parameters, on the colour changes and chemical composition of a beech wood surface. The results showed that the lightness clearly decreased with increasing laser power and density. At the highest laser power and the highest raster density, the ΔL* value was 51.3. The values of coordinates a* and b* moderately increased up to a raster density of 5 mm−1; then, with a subsequent raster density increase, the values of these coordinates decreased again. However, the coordinate values were positive in all cases. Even the lowest laser power and raster density resulted in conspicuous discolouration or even a completely new colour compared to the original (ΔE = 10) of the beech wood surface. Further increases in the laser power and raster density resulted in progressively pronounced colour differences and a darker brown colour of the surface. The ATR-FTIR chemical analysis of the beech wood surface revealed that discolouration was mainly caused by heat-induced processes associated with the degradation of carbonyl groups (C=O) in lignin and hemicelluloses. The splitting of C=O bonds induced changes in the content of chromophores responsible for the natural wood colour and for the engraving-related discolouration. The study demonstrates that the amount of energy supplied onto the wood surface by a laser beam using diverse combinations of radiation parameters can be represented by a single variable: the total irradiation dose. The functional relation detected between this variable and the colour differences may serve as a basis for using a controlled laser beam for targeted wood surface discolouration to improve the quality of patterns transferred onto a wood surface. Knowledge of this relation will enable the targeted setting of the laser parameters during engraving so that the laser beam can be used as a tool for transferring high-quality patterns onto wood surfaces.

Risk Factors of Esophageal Fistula Associated with Volumetric Modulated Arc Therapy for Esophageal Squamous Cell Cancer.

To investigate risk factors for esophageal fistula in esophageal squamous cell cancer (ESCC) patients who treated with volumetric modulated arc therapy (VMAT). A retrospective analysis was performed on 171 ESCC patients treated with VMAT at Hefei Cancer Hospital, Chinese Academy of Sciences, from February 2017 to February 2021. Clinical and dosimetric parameters, including age, gender, feeding channel, tumor location, T stage, ulcerative tumor, were recorded. Univariate and multivariate logistic regression were used to determine risk factors for esophageal fistula. The predictive accuracy of the constructed nomogram was assessed using a receiver operating characteristic (ROC) curve and calibration curves. Esophageal fistula occurred in 12.87% (22/171) of all the patients. Univariate analysis showed that gender, age, diabetes, T4 stage, ulcerative tumor, total radiation dose, maximum gross tumor volume (GTV) diameter, and GTV length correlated with the incidence of esophageal fistula. Multivariable analysis highlighted gender, age, diabetes, T4 stage, and total radiation dose as significant predictors. A predictive nomogram including these five factors was developed and showed an AUC of 0.876 (95% CI 0.807-0.946), a C-index of 0.847, and a corrected C-index of 0.833. Gender, age, diabetes, T4 stage, and total radiation dose emerged as significant risk factors for esophageal fistula in ESCC patients undergoing VMAT. The developed nomogram provides a reliable tool to predict the risk of esophageal fistula risk in this cohort.

Reduced dose helical CT scout imaging on next generation wide volume CT system decreases scan length and overall radiation exposure

PurposeTraditional CT acquisition planning is based on scout projection images from planar anterior-posterior and lateral projections where the radiographer estimates organ locations. Alternatively, a new scout method utilizing ultra-low dose helical CT (3D Landmark Scan) offers cross-sectional imaging to identify anatomic structures in conjunction with artificial intelligence based Anatomic Landmark Detection (ALD) for automatic CT acquisition planning. The purpose of this study is to quantify changes in scan length and radiation dose of CT examinations planned using 3D Landmark Scan and ALD and performed on next generation wide volume CT versus examinations planned using traditional scout methods. We additionally aim to quantify changes in radiation dose reduction of scans planned with 3D Landmark Scan and performed on next generation wide volume CT. MethodsSingle-center retrospective analysis of consecutive patients with prior CT scan of the same organ who underwent clinical CT using 3D Landmark Scan and automatic scan planning. Acquisition length and dose-length-product (DLP) were collected. Data was analyzed by paired t-tests. Results104 total CT examinations (48.1 % chest, 15.4 % abdomen, 36.5 % chest/abdomen/pelvis) on 61 individual consecutive patients at a single center were retrospectively analyzed. 79.8 % of scans using 3D Landmark Scan had reduction in acquisition length compared to the respective prior acquisition. Median acquisition length using 3D Landmark Scan was 26.7 mm shorter than that using traditional scout methods (p < 0.001) with a 23.3 % median total radiation dose reduction (245.6 (IQR 150.0–400.8) mGy cm vs 320.3 (IQR 184.1–547.9) mGy cm). CT dose index similarly was overall decreased for scans planned with 3D Landmark and ALD and performed on next generation CT versus traditional methods (4.85 (IQR 3.8–7) mGy vs. 6.70 (IQR 4.43–9.18) mGy, respectively, p < 0.001). ConclusionScout imaging using reduced dose 3D Landmark Scan images and Anatomic Landmark Detection reduces acquisition range in chest, abdomen, and chest/abdomen/pelvis CT scans. This technology, in combination with next generation wide volume CT reduces total radiation dose.

The effect of Fiber Optic RealShape technology on perioperative and postoperative outcomes following complex abdominal aortic repair.

Ongoing innovations in the minimally invasive management of complex abdominal aortic aneurysms, including physician-modified endografts (PMEG) and, more recently, Fiber Optic RealShape (FORS) technology, have allowed vascular surgeons to expand the surgical indications for and complexity of care to this multifaceted patient population. Prior analyses have demonstrated intraoperative advantages of Fiber Optic RealShape in the management of complex abdominal aortic aneurysms for lower total procedural radiation and cannulation tasks; however, few analyses have evaluated the technology's effect on perioperative and postoperative outcomes. All PMEGs performed at our institution between 2020 and 2024 were reviewed retrospectively. Primary intraoperative and perioperative outcomes included fluoroscopy time and dose, target vessel cannulation failure, target vessel dissection or perforation, and perioperative complications. Primary postoperative (6-month) outcomes included target vessel related (type Ic or IIIc) endoleak and target vessel instability, defined as any branch-related complication leading to aneurysm rupture, death, occlusion, component separation, or reintervention. Inverse probability of treatment weighting was used to account for factors of clinical significance. The χ2 test, logistic regression, and Cox regression were used to evaluate perioperative outcomes in the weighted cohort. Between 2020 and 2024, 118 patients received a PMEG: 49 with Fiber Optic RealShape (FORS) and 69 using standard fluoroscopy. Baseline characteristics were similar between groups. After weighting, use of FORS exhibited lower fluoroscopy time (38minutes vs 56minutes; P< .01) and air Kerma (429mGy vs 655mGy; P= .01). Between FORS and standard fluoroscopy, there were no differences noted in target vessel cannulation failure (4.7% vs 1.0%) or in intraoperative or perioperative target vessel perforation (1.9% vs 1.0%) or dissection (6.7% vs 2.1%) (all P > .05). Perioperative complications were similar between groups (22% vs 21%), including spinal cord ischemia (temporary, 8.4% vs 6.1%; permanent, 2.0% vs 3.9%) and bowel ischemia (0% vs 2.6%). FORS use did demonstrate lower rates of target vessel instability (1.2% vs 10%; P= .02) at 6months; however, this difference did not persist on multivariable analysis. Since the implementation of FORS at our institution, when compared with standard fluoroscopy, there have been significantly lower intraoperative fluoroscopy times and total radiation doses, with no difference in target vessel cannulation failure, dissection, perforation, perioperative complications, or target vessel instability at 6months after a PMEG. Although these data may represent our institution's gradual improvement in expertise with this new technology, our results underscore the importance of additional analyses on this evolving technology as it becomes more integrated into the standard practice of the management of complex aortic pathologies.

Fractionated radiotherapy with stereotactic radiosurgery boost controls gross disease in grade 2 meningioma

Opportunity exists for improved local control rates of grade 2 meningiomas that recur despite maximal surgical resection and adjuvant fractionated radiotherapy (RT). We describe a dose escalation strategy of increasing the total tumor radiation dose by adding a stereotactic radiosurgery (SRS) boost targeting gross disease to fractionated RT. A single-institution retrospective cohort of patients from 2009-2023 with grade 2 meningioma treated with surgical resection, fractionated RT, and SRS boost were evaluated for baseline characteristics, local disease control, and adverse events (AE). Fourteen meningioma patients were included. Ten patients (71.4%) underwent radiosurgery at initial diagnosis, while 4 patients (28.6%) were treated for recurrent disease. The median fractionated dose was 54 Gy, while the median dose for SRS was 7.5 Gy. Among the 13 patients with follow-up available, median follow-up was 34 months. Three patients (23%) had treatment failures; however, none occurred within the SRS volume and 2 thirds occurred in patients treated for recurrent disease. Eighteen-month progression-free survival was 92.3%, while 18-month overall survival was 100%. Most patients experienced no or mild AEs; however, 3 patients (23%) experienced a high-grade (Common Terminology Criteria for Adverse Events v5.0 grade ≥3) AE including radiation necrosis, seizures, and cognitive decline. We found 100% in-field local control at 3 years from an SRS boost to fractionated RT targeting gross disease with an acceptable toxicity profile, suggesting this may be an effective and improved adjuvant treatment strategy in patients with grade 2 meningioma.

"When Less is More": Paradigm Shifts in Radiation Treatment for Early-Stage Breast Cancer.

Recent advancements in the treatment of early-stage breast cancer have significantly shifted the radiotherapy landscape. Traditionally, the standard of care included lumpectomy followed by endocrine therapy and 3-5 weeks of adjuvant radiation targeting the entire unilateral breast. This review summaries modern trials, emphasizing data reported since 2019 that have changed radiation treatment paradigms. Ultra-hypofractionated treatment regimens have enabled radiation oncologists to deliver the total radiation dose in as few as 5 treatments over 1 week for select patients. Partial breast irradiation, treating only the breast tissue nearest to the lumpectomy cavity, has also emerged as an effective and well-tolerated treatment. Furthermore, a growing body of evidence supports the safety of omitting radiation completely for certain older adults with low-risk disease. Ongoing research in areas such as precision cancer care, treatment de-escalation, and toxicity prevention and management reflects a broader shift toward shared decision-making in medicine and individually tailored treatment paradigms. As research progresses, treatment options will continue to evolve. Advances in radiation oncology will give the oncology team a growing array of tools to custom treatment plans to individual patient risks and toxicity concerns. Knowledge of radiation advances should be used to facilitate shared decisions with patients about the balance of treatment efficacy, toxicity, and quality of life, with the ultimate goal of promoting high-quality, personalized, and patient-centered cancer care.

Delayed Facial Nerve Dysfunction Following CyberKnife® Radiosurgery for Vestibular Schwannoma.

The incidence and risk factors for facial nerve dysfunction (FND) following CyberKnife® therapy for vestibular schwannoma (VS) remain poorly understood. This study investigates whether differential radiation doses to vulnerable segments of the facial nerve may be associated with FND outcomes. Patients were identified who underwent CyberKnife® radiosurgery for VS at a single institution. Basic demographics, tumor characteristics, and facial nerve function were collected. Total radiation doses to tumor, internal auditory canal (IAC), and labyrinthine segment of facial nerve (LSFN) were evaluated. Six out of 64 patients experienced FND following CyberKnife® treatment for VS (9.38%, 6/64). Patients with FND were compared to those without FND (control). Of the 64 patients, complete radiation records were obtained for 30 patients (6 FND vs. 24 control). There were no significant differences in demographic or tumor characteristics between control and FND cohorts. More severe FND (HB ≥ 4) had significantly larger tumors (3.74 vs. 1.27 cm3, p = 0.037) with directionally decreased time to FND (3.50 vs. 33.5 months, p = 0.106) than patients with HB < 4, respectively. There were directionally, nonsignificant differences between maximum radiation doses to the LSFN (2492.4 vs. 2557.0 cGy, p = 0.121) and IAC (2877.3 vs. 2895.5 cGy, p = 0.824) between the control and FND cohorts, respectively. FND may represent an underrecognized sequelae of CyberKnife® radiosurgery for VS that can occur many months following treatment. Further studies are needed to elucidate the effect of differential radiation exposure to the facial nerve with FND following treatment. 3 (Retrospective Cohort Study) Laryngoscope, 134:5080-5086, 2024.

Improvement in cranial neuropathies following stereotactic radiotherapy as primary treatment for skull base meningiomas

Purpose Many patients with skull base meningiomas (SBMs) develop cranial neuropathies, though there is a paucity in literature regarding cranial neuropathy improvement following treatment. This is even more profound when isolating for patients who received stereotactic radiotherapy (SRT) as their primary treatment without additional open surgery. Our goal was to investigate the effect of SRT on cranial neuropathies secondary to SBMs and identify predictors of favourable treatment response. Materials and methods A single-center retrospective case-control study was performed assessing factors associated with cranial neuropathy improvement in patients with SBMs treated with SRT alone. Patients diagnosed with SBMs, having a cranial neuropathy, and treatment with radiation monotherapy were included. Patients without SBMs or who underwent surgery treatments were excluded. Patients with olfactory and vestibulocochlear neuropathies were ultimately excluded due to sample sizes. Subgroup analysis was performed assessing predictors of improvement for optic, extraocular, and trigeminal neuropathy. Statistical analysis was completed using R version 4.0 (R Foundation for Statistical Computing, Vienna, Austria). Results Eighty-five patients met the inclusion criteria of SBMs treated with SRT alone. Forty-five patients (52.9%) had improvement in their symptoms. Among the entire cohort, there was no significant difference between gender, age, tumour location, type of neuropathy, duration of symptoms, tumour volume, total radiation dose, or follow-up duration between those who did and those who did not improve. Subgroup analysis demonstrated significant improvement with younger age at diagnosis of optic neuropathy (50.7 vs 59.6 years, p = 0.04), shorter duration of symptoms prior to radiation in those with extraocular neuropathy (3.0 vs 11.5 months, p = 0.02), and lower radiation dose in those with trigeminal neuropathy (50.0 vs 54.0 Gy, p = 0.01). Conclusions This study demonstrates that SRT alone resulted in cranial neuropathy improvement in more than half of patients with SBM and identifies factors predictive of symptom resolution.

The Role of Micro Propulsion in Enabling Autonomous Operations of Nanosatellites

Micro-Electro-Mechanical Systems (MEMS)-based propulsion devices have significant potential for providing high specific power. The application of Micro Power Generation technology to space propulsion systems can enhance orbit and station-keeping capabilities, potentially at lower costs. New-generation spacecraft and satellites are becoming smaller and require micro-propulsion systems for all aspects of their operations. The development of micro-propulsion systems with associated combustors for micro-electricity generation, utilizing liquid fuel, presents major challenges in fuel injection, mixing, combustion, and chemical reactor systems. A micro-spacecraft with high-accuracy station-keeping and attitude control capabilities needs to have low mass and deliver small impulses. Each nanosatellite will weigh a maximum of 10 kg, including the propellant mass. Provisions for orbital manoeuvres, attitude control, multiple sensors, and instruments, along with full autonomy, will result in a highly capable miniaturized satellite. All onboard electronics will endure a total radiation dose of 100 k rads over a two-year mission lifetime. Nanosatellites designed for in-situ measurements will be spin-stabilized and equipped with a complement of particles and fields instruments. Nanosatellites intended for remote measurements will be three-axis stabilized and equipped with imaging and radio wave instruments. Key technologies under development include: advanced, miniaturized chemical propulsion systems; miniaturized sensors; highly integrated, compact electronics; autonomous onboard and ground operations; miniaturized onboard orbit determination methods; onboard RF communications capable of transmitting data to Earth from significant distances; lightweight and efficient solar array panels; lightweight, high-output battery cells; a miniaturized heat transport system; lightweight yet strong composite materials for nano-satellite and deployer-ship structures; and simple, reusable ground systems.

Radiation exposure and protection advice after [177Lu]Lu-DOTA-TATE therapy in China

BackgroundWe conducted a study on radiation exposure in patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) treated with [177Lu]Lu-DOTA-TATE in China for the first time, aiming to provide guidance and reference for radiation protection in this regard. A total of 30 GEP-NENs patients who received [177Lu]Lu-DOTA-TATE therapy were recruited in the study. We measured the external dose rate (EDR) values of each patient during the injection and 0–6 h post-administration period, as well as the radiation dose (RD) values to healthcare nurses and the surrounding environment. We performed a double exponential curve fitting and estimated the RD to the public from patients discharged at different times after [177Lu]Lu-DOTA-TATE therapy.ResultsAmong the 30 patients, 27 patients completed 4 cycles of [177Lu]Lu-DOTA-TATE treatments, the estimated RD to the public indicated that for adult family members, children above 10 years old, children aged 3–10 and coworkers of the patients, patients could begin daily contact at least 24 h, 48 h, 144 h and 192 h after injection to ensure that the total RD values after four treatments not exceed the limit. During the hospitalization of patients receiving [177Lu]Lu-DOTA-TATE, the cumulative dose received by the administering nurses and to the ward environment were both well below the national RD limits.ConclusionsThis study conducted a fitting analysis of the decay pattern of EDR values in GEP-NENs patients undergoing [177Lu]Lu-DOTA-TATE therapy, in order to establish guidelines for patient discharge timing and provide recommendations for radiation protection for the general public after patient discharge.Trial registration A Study Comparing Treatment With Lutetium[177Lu] Oxodotreotide Injection to Octreotide LAR in Patients With GEP-NETs, NCT05459844. https://clinicaltrials.gov/study/NCT05459844?cond=NCT05459844&rank=1. Registered 5 July 2022.

(Invited) Blended Positive Electrode Materials for Li-Ion Batteries: Electrode Dynamics and Operando XRD

Transport electrification has resulted in an expansion of the Li-ion battery application from Wh to kWh storage. This has brought up additional requirements to improve performance (e.g. power, cycle life) enhance of sustainability and decrease of cost. Blending different active materials at the same cell electrode, an empirical approach commonly used for primary cells, has been readily applied to commercial EV Li-ion batteries mostly on the positive side. The global aim is to promote positive synergetic effects between the different electrode components, which have unfortunately received limited attention at the fundamental research level.Materials with fast reaction kinetics, such as LiMn2O4 (LMO) can sustain significantly higher effective rates than the nominal rate applied to the electrode. This has motivated the widespread commercial use of NMC:LMO blends as LiNixMnyCozO2 (x+y+z=1, NMC) despite having slow kinetics, exhibits high capacity (especially for large amounts of Ni) and the addition of LMO lowers overall costs while enhancing power performance. Olivine LiMPO4 (M=Fe, Mn) based blends have a lower presence in commercial cells to date but they have also deserved attention at the laboratory scale as they can as well exhibit fast kinetics and are based on low cost abundant transition metals.Results will be presented related to different blends, consisting of combinations of LMO, NMC, LiFePO4 (LFP) and LiFe0.35Mn0.65PO4 (LFMP). Electrochemical experiments coupled to time-resolved synchrotron operando X-ray diffraction experiments enable to capture charge transfer events between blend components which are dependent on both voltage profile and kinetics of individual blend components. The results demonstrate the significant impact of the voltage profiles of individual materials on the current distribution, with the effective C-rate of each component varying throughout the state of charge (SoC).Finally, systematic operando synchrotron X-ray diffraction and absorption experiments will be presented for NMC and LFP with diverse experimental conditions (cell type, radiation energy etc.) to illustrate the existence of beam-induced effects which may bias interpretation of results. These range from total reaction inhibition to partial hindrance and negligible deviations from the expected mechanism, and have been consistently observed across various experimental conditions, photon energies, photon fluxes and exposure times. The total radiation dose per cycle seems to be a useful predictor of the magnitude of beam-induced electrochemical delay and could serve as a guideline to define reliable measurement protocols.

RADIATION PROTECTION WHEN USING SOURCES OF IONIZING RADIATION IN MEDICINE

Problem statement. The use of sources of ionizing radiation (SIR) in medicine is necessary for establishing diagnoses and treating patients, as well as measures for visualization and localization of various formations when using radiopharmaceuticals to study the functions and structure of organs. But when using sources of ionizing radiation, risks from radiation exposure to patients and staff are possible. Such risks are safety concerns in nuclear medicine procedures. The application of SIR requires proper radiation protection in accordance with the norms and rules of nuclear and radiation safety. Purpose of the article is to develop recommendations for improving radiation safety measures in medical institutions of Ukraine on the basis of an analytical review of regulatory and scientific and technical literature on radiation safety when using ionizing radiation in nuclear medicine in the countries of the world. Conclusions. During medical research using sources of ionizing radiation, risks from radiation exposure to patients and staff are possible. Radiation safety should consider: duration of exposure, distance of patients and staff from the source of radiation and use of appropriate protection. Dosimeters for measuring the total radiation dose must be worn by all personnel of the radiology department of the hospital. For interventional radiologists, lead aprons and thyroid shields are the primary means of radiation protection that must be worn at all times during the procedure. It is recommended that criteria for clinical audits be included in standards and accreditation and certification programs related to medical practice using ionizing radiation. It is advisable to introduce the teaching of clinical audit into the initial and continuing education and curricula of the professional training of medical workers, including administrative and managerial profiles. In the radiological laboratories of Ukraine, it is expedient to implement the recommendations of the EU Atomic Energy Commission in accordance with Council Directive 2013/59/Euratom. Clinical audit of medical radiological procedures will provide an opportunity to improve the quality and safety of medical services, as well as patient health care.

NEW APPROACHES TO CROSSLINKING IN COMBINATION WITH REFRACTIVE KERATOMODELING IN CORNEAL ECTASIA

Objective: To consider new approaches to crosslinking in combination with refractive keratomodeling in corneal ectasia of various etiologies.Methods: The work is based on clinical observations of the immediate and remote results of prophylactic and therapeutic corneal crosslinking with argon-fluorine excimer laser radiation (over 700 operations) over periods from 1 month to 13 years. Particular emphasis was placed on the formation of a Bowman-like membrane structure on the ablation surface and local exposure with a personalized gradient refractive profile of the total dose of radiation to achieve a greater keratomodeling effect. Rapid transition without additional calibrations to energy densities below the ablation threshold was carried out on the Russian excimer laser “Microscan Visum-500”.Results: Experimental and clinical studies have shown that excimer laser radiation on argon-fluorine can be used for corneal crosslinking, with energy densities in the pulse being below the ablation threshold. The advantage of excimer laser crosslinking was scanning with a narrow beam, which disrupts the oxygenation of the corneal stroma to a lesser extent and allows for the implementation of personalized local refractive keratomodeling based on keratotopography or aberrometry data. In this case, the induced secondary radiation covers all four peaks of maximum absorption by riboflavin. The use of subablative energy densities during irradiation of the cornea in the personalized PRK mode made it possible to locally affect the ectasia zone and enhance the refractive effect due to the gradient distribution of the total radiation dose.Conclusion: Radiation from an argon-fluorine excimer laser opens up new possibilities for refractive ablative and non-ablative refractive keratomodeling of the cornea in combination with laser-induced crosslinking in keratoconus and secondary keratoectasias of various etiologies.