Effective Dose Research Articles

Features, reasons, and significance of radon and thoron attributable radiological dose in the indoor environment

Humans receive around 50% of natural radiation dose due to 222Rn (radon), 220Rn (thoron) and their decay products. Several field campaigns measuring these gases and the decay products in different regions of India have been conducted in the recent past. Some of these studies measured indoor activity concentration and/or dose due to these gases and the associated decay products. This work compares the fraction of 222Rn and decay products and 220Rn and decay products in inhalation dose for 10 studies conducted in Uttarakhand state. It is seen that AEDT (annual effective dose due to 220Rn and decay products) for these regions varies between 21 and 48% and it is significantly higher than the averaged worldwide reference value of 6%. Based on elaborative measurements performed in the Bageshwar district (present work), Almora and Nainital districts (our previous campaigns); the reasons for this high value have been explored. It was observed that a higher source term for mud houses could be the main reason for the high AEDT range. Interestingly, preliminary analysis revealed that the fraction is higher for the dwellings situated at higher altitudes thus indicating the role of the unavailability of modern building construction materials at remote locations. The study highlights the significant contribution of thoron in the Indian Himalayas.

GRAIN Study - Granulocytes Against Infections - Use of granulocyte transfusion in haematopoietic stem cell transplant

Granulocyte transfusions (GTx) combat infections in neutropenic patients. However, immune-mediated off-target effects in transplant settings are unknown. Between January 2020 and December 2021, all transplants that used GTx during the peri-transplant period were analysed. Engraftment, infections, and days to clearance were retrieved from clinical records. Overall survival is compared with the mean total PMN count and the different products. Pooled buffy coat was used in 110 patients (98 %), of which 38 (34 %) additionally received an apheresed product. The median days of GTx was 4. The median bags pooled to prepare a single buffy coat product was 4. The mean total PMN count was 0.98 × 1010/ L granulocytes per pooled buffy coat and 1.93 × 1010/L granulocytes per apheresis product. A higher PMN count (>1 × 1010/L) was achieved in 48 % with pooled buffy coat versus 85 % with apheresis. Respiratory worsening occurred in 39 % receiving GTx. All patients who received granulocytes had engrafted with a median time of 14 days for neutrophil and 20 days for platelet engraftment. Blood cultures cleared in 81 %, whereas only 28 % cleared other cultures. Fungal pneumonia cleared in 25 %, and invasive fungal sinusitis or otitis cleared in 50 %. Overall survival was 47 %, non-significantly higher (57 % vs 39 %, P = 0.1) with a higher PMN dose. The pooled buffy coat is an affordable alternative to apheresis for an effective PMN dose. Ease of availability and low cost of pooled buffy coat, with comparable overall survival points toward a safe and efficacious product, in the peri-transplant period.

First-in-human study of dosimetry, safety and efficacy for [177Lu]Lu-P15-073: a novel bisphosphonate-based radioligand therapy (RLT) agent for bone metastases.

Bisphosphonates are pivotal in managing bone tumors by inhibiting bone resorption. This study investigates the therapeutic potential of [177Lu]Lu-P15-073, a novel bisphosphonate, for radioligand therapy (RLT) in bone metastases. Ten patients (age 35 to 75) with confirmed bone metastases underwent therapy with a single dose of [177Lu]Lu-P15-073 (1,225 ± 84 MBq, or 33 ± 2 mCi). Prior to treatment, bone metastases were verified via [99mTc]Tc-MDP bone scans. Serial planar whole-body scans monitored biodistribution over a 14-day period. Dosimetry was assessed for major organs and tumor lesions, while safety was evaluated through blood biomarkers and pain scores. Serial planar whole-body scans demonstrated rapid and substantial accumulation of [177Lu]Lu-P15-073 in bone metastases, with minimal uptake in blood and other organs. The absorbed dose in the critical organ, red marrow, was measured at (0.034 ± 0.010 mSv/MBq), with a notably low normalized effective dose (0.013 ± 0.005 mSv/MBq) compared to other 177Lu-labeled bisphosphonates. Persistent high uptake in bone metastases was observed, resulting in elevated tumor doses (median 3.12Gy/GBq). Patients exhibited favorable tolerance to [177Lu]Lu-P15-073 therapy, with no new instances of side effects. Additionally, 87.5% (7/8) of patients experienced a significant reduction in pain scale (numerical rating scale, NRS, from 5.1 ± 2.3 to 3.0 ± 1.8). The tumor-background ratio (TBRmean) of [99mTc]Tc-MDP correlated significantly with [177Lu]Lu-P15-073 uptake (P < 0.01), indicating its potential for prediction of absorbed dose. This study demonstrates the safety, dosimetry, and efficacy of a single therapeutic dose of [177Lu]Lu-P15-073 in bone metastases. The treatment was well-tolerated with no severe adverse events. These findings suggest that [177Lu]Lu-P15-073 holds promise as a novel RLT agent for bone metastases.

Environmental assessment of toxic heavy metals and natural radionuclides in irrigation water from Rustenburg, South Africa

Water is a transparent, tasteless and odourless inorganic compound, essential for life and sustainable development. It is important for food and energy production, socio-economic growth, healthy ecosystems and human existence. Global attention is given to water quality monitoring due to the role it plays in human exposure to different kinds of contaminants, including radioactive and toxic contaminants from industrial, agrochemicals, mining and other anthropogenic activities. This work presents the results of measured natural radionuclides and toxic heavy metals in Rustenburg, and their associated non-carcinogenic and carcinogenic risk. The average concentrations of Cd, Cu, Co, Fe, Ni, Mn, Pb and Zn are 0.00007 mg/l, 0.0087 mg/l, 0.0033 mg/l, 0.0636 mg/l, 0.0052 mg/l, 0.0217 mg/l, 0.0003 mg/l and 0.0047 mg/l respectively and are below the safe limit of toxic heavy metals in water. The activity concentration of 40K and 238U ranges from 7.07 Bq/l to 13.2 Bq/l and 1.24 × 10−04 Bq/l to 1.09 × 10−02 Bq/l, with a mean activity concentration of 11.6 Bq/l and 2.78 × 10−03 Bq/l respectively. 232Th was not found in all measured water samples. The estimated average committed effective dose from ingestion of natural radionuclides was observed to be below 170 μSv/yr for 40K, 120 μSv/yr for 232Th and 238U, and a total of 290 μSv/yr reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. The assessment of human health risks resulting from exposure to toxic heavy metals shows negligible carcinogenic and non-carcinogenic health risks to the exposed population, making the water sources from which the sample was collected, safe for agricultural and domestic use. The obtained results will also serve as reference data for future environmental studies.

Feasibility of ultra-low activity 18F-FDG PET/CT imaging in children.

To investigate the feasibility of pediatric 18F-FDG total-body PET/CT imaging with an ultra-low activity and explore an optimized acquisition time range. A total of 38 pediatric patients were prospectively enrolled and underwent dynamic total-body PET/CT imaging using ultra-low 18F-FDG activity (0.37 MBq/kg). The 60-minute list-mode raw data were acquired and then reconstructed as static PET images by using 50-51, 50-52, 50-53, 50-54, 50-55, 50-58, 50-60, and 45-60 minutes data, which were noted as G1, G2, G3, G4, G5, G8, G10, and G15, respectively. Image qualities were subjectively evaluated using the Likert scale and were objectively evaluated by the quantitative metrics including standard uptake value (SUV), signal-to-noise ratio (SNR), target-to-background ratio (TBR), and contrast-to-noise ratio (CNR). The injected activity of FDG was 13.38 ± 5.68 MBq (4.40-28.16 MBq) and produced 0.58 ± 0.19 mSv (0.29-1.04 mSv) of effective dose. The inter-reader agreement of subjective image quality was excellent (kappa = 0.878; 95% CI, 0.845-0.910). The average scores of image quality for G1-G15 were 1.10 ± 0.20, 2.03 ± 0.26, 2.66 ± 0.35, 3.00 ± 0.27, 3.32 ± 0.34, 4.25 ± 0.30, 4.49 ± 0.36, and 4.70 ± 0.37, respectively. All image scores are above 3 and all lesions are detectable starting from G8. SNRs of backgrounds, TBRs, and CNRs were significant differences from the control group before G8 (all P < 0.05). The image quality of the 8 min acquisition for pediatric 18F-FDG total-body PET/CT with an ultra-low activity could meet the diagnostic requirements. This study confirms the feasibility of ultra-low dose PET imaging in children, and its methods and findings may guide clinical practice. pediatric patients will benefit from reduced radiation doses.

Radiation therapy in the hypofractionation mode on the Halcyon elite linear accelerator: the first experience of St. Petersburg city clinical oncology dispensary

Stereotactic radiation therapy in the hypofractionation mode is a method in which high doses of ionizing radiation (more than 3 Gy per fraction) are delivered in a small number of fractions (from 2 to 5). Treatment and the process of preparation for it are carried out using special fixing devices, dosimetric planning techniques of high conformity, with control of the treatment position using x-ray imaging. which makes it possible to ensure the required irradiation accuracy. The advantages are a shorter course of treatment compared to standard fractionation, a high biologically effective dose, a reduced effect of tumor repopulation, greater efficiency under hypoxic conditions, and satisfactory results when irradiating radioresistant tumors. The article presents clinical cases of the use of hypofractionation modes on the Halcyon elite linear accelerator.

Intensive care unit continuous kidney replacement therapy: time to change dosage recommendations?

Continuous kidney replacement therapy (CKRT) is the predominant form of acute kidney support used for hemodynamically unstable adult ICU patients with severe AKI (KDIGO stage 3). The success of CKRT depends on the achieved doses. Practice patterns worldwide are highly variable. A contemporary understanding of treatment adequacy is essential. The KDIGO AKI clinical guidelines recommend delivering effluent volumes of 20-25ml/kg/hour for CKRT in the ICU setting, with the caveat that higher prescribed doses (25-30ml(kg/h) may be necessary to achieve adequate delivered CKRT doses. The reference landmark trials provide definitive evidence that increases of delivered CKRT doses beyond the recommended dose are not beneficial for unselected ICU patients with severe AKI. However, the minimum delivered CKRT intensity at which underdosing becomes harmful remains unknown. The answer to this question has clinical relevance (dosing of critically ill patients with obesity or Covid-19 disease, minimizing adverse effects of CKRT) and a relevant impact on the costs of CKRT. The delivered dose of CKRT for Japanese ICU patients with severe AKI has been generally smaller (median 15ml/h/kg) than the recommended delivered KDIGO dose. The most recently published retrospective cohort study by Okamoto et al. demonstrated that low delivered CKRT doses were associated with a higher mortality among critically ill patients with severe AKI. These data challenge the nation-wide accepted hypothesis that a lower limit of delivered CKRT (< 20ml/ kg/h) may adequately control uremia/volume overload. Thus, there is an unmet clinical need for prospective randomized trials defining the minimal effective dose of CKRT. Given the dynamic nature of the precipitating critical illness and the natural course of most episodes of AKI, CKRT dose targets are likely to vary. Doses should be tailored to the needs of the individual patient within the limits of the KDIGO guideline recommendations. The Japanese experience with low-dose CKRT is not practice changing.

Image Quality and Lesion Detectability of Low-Concentration Iodine Contrast and Low Radiation Hepatic Multiphase CT Using a Deep-Learning-Based Contrast-Boosting Model in Chronic Liver Disease Patients.

This study investigated the image quality and detectability of double low-dose hepatic multiphase CT (DLDCT, which targeted about 30% reductions of both the radiation and iodine concentration) using a vendor-agnostic deep-learning-based contrast-boosting model (DL-CB) compared to those of standard-dose CT (SDCT) using hybrid iterative reconstruction. The CT images of 73 patients with chronic liver disease who underwent DLDCT between June 2023 and October 2023 and had SDCT were analyzed. Qualitative analysis of the overall image quality, artificial sensation, and liver contour sharpness on the arterial and portal phase, along with the hepatic artery clarity was conducted by two radiologists using a 5-point scale. For quantitative analysis, the image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. The lesion conspicuity was analyzed using generalized estimating equation analysis. Lesion detection was evaluated using the jackknife free-response receiver operating characteristic figures-of-merit. Compared with SDCT, a significantly lower effective dose (16.4 ± 7.2 mSv vs. 10.4 ± 6.0 mSv, 36.6% reduction) and iodine amount (350 mg iodine/mL vs. 270 mg iodine/mL, 22.9% reduction) were utilized in DLDCT. The mean overall arterial and portal phase image quality scores of DLDCT were significantly higher than SDCT (arterial phase, 4.77 ± 0.45 vs. 4.93 ± 0.24, AUCVGA 0.572 [95% CI, 0.507-0.638]; portal phase, 4.83 ± 0.38 vs. 4.92 ± 0.26, AUCVGA 0.535 [95% CI, 0.469-0.601]). Furthermore, DLDCT showed significantly superior quantitative results for the lesion contrast-to-noise ratio (7.55 ± 4.55 vs. 3.70 ± 2.64, p < 0.001) and lesion detectability (0.97 vs. 0.86, p = 0.003). In patients with chronic liver disease, DLDCT using DL-CB can provide acceptable image quality without impairing the detection and evaluation of hepatic focal lesions compared to SDCT.

MQ232, A Snake Toxin Derivative for Treatment of Hyponatremia and Polycystic Kidney Diseases

Background: Vaptans were developed at the end of the previous century as V2R antagonists. Tolvaptan is the most prescribed vaptan for hyponatremia and the autosomal polycystic kidney disease (ADPKD). However, its use is not as widespread as it should be due to price issues, a narrow therapeutic window and some side effects. With the aim of discovering new efficient and safer V2R antagonists, we screened animal venoms and identified several interesting peptide toxins. Among them, MQ1 displayed such unique biological properties in that regard that it was the starting point for the development of a potential drug candidate. Methods: Human T-cell assays and bioinformatics was used to mitigate MQ1 immunogenicity risk. The MQ232 biodistribution in mice was done by positron emission tomography (PET). Pharmacodynamics, pharmacokinetics, acute and chronic toxicity tests were performed on control rats. A rat experimental model of dDAVP-induced hyponatremia, an ex vivo mice model of renal cysts and a mice orthologous model of ADPKD were used to validate MQ232 efficacy in these pathologies. Results: Three mutations were introduced in MQ1 to mitigate its immunogenicity risk. A fourth gain-of-function mutation was added to generate MQ232. MQ232’s safety was demonstrated by a first toxic dose as high as 3,000 nmol/kg and a strong kidney organ selectivity by PET imaging, while showing almost no interaction with the liver. MQ232’s efficacy was first demonstrated with an effective dose of 3 nmol/kg in a hyponatremic model, and then in polycystic kidney models on which MQ232 significantly reduced cyst growth. Conclusions: We demonstrated, employing diverse translational techniques and minimizing animal use, MQ232's safety and efficacy in several rodent models of hyponatremia and ADPKD.

ASSESSMENT OF THE LEVELS OF NATURAL RADIOACTIVITY AND THE POSSIBILITY OF RADIATION RISKS IN SOIL SAMPLES TAKEN FROM DIFFERENT LOCATIONS IN SOUTHERN ALMAZAR-ALKARAK, JORDAN

A wide study of environmental radioactivity levels in soil samples from Southern Almazar-Alkarak in Jordan was performed to develop a radiological map of the area. 15 soil samples were collected from different locations across the region and subjected to analysis using a high-purity germanium detector (HPGe). The study showed that the average levels of natural radionuclides 226Ra, 232Th, 238U and 40K were 34.5±0.98, 25.6±1.3, 32.2±3.7 and 278.5±15.7 Bq.kg−1, respectively. Also, to evaluate the radiological danger, the radium equivalent activity (Raeq) is calculated, absorbed gamma dose rate (D), annual effective dose equivalent (AEDE) and external hazard index (Hex), internal hazard index (Hin). The average values for these parameters were determined to be 92.5 Bq.kg−1, 43.0 nGy h−1, 52.7 µSv y−1 and 0.25Bq.kg−1, 0.34Bq.kg−1 respectively. The values of the gathered samples stay below the allowable limits. Consequently, the examined region does not present any radiation risk to the general population. Moreover, it has been discovered that there is no concentration of 137Cs radionuclide activity in the studied area.

First-in-human study of D6-[18F]FP-(+)-DTBZ, a novel VMAT2 tracer: whole-body biodistribution and brain PET comparison with [18F]FP-(+)-DTBZ (AV-133)

BackgroundIn the central nervous system, type 2 vesicular monoamine transporters (VMAT2) are responsible for the reuptake of monoamines from synaptic junction back to pre-synaptic terminal vesicles. These transporters are functionally crucial as they reflect the integrity of monoamine neurons. D6-[18F]FP-(+)-DTBZ, a novel deuterated VMAT2 radioligand, has shown promise as a potential PET tracer for the diagnosis of Parkinson’s disease (PD). This study evaluates the biodistribution and dosimetry of D6-[18F]FP-(+)-DTBZ and includes a head-to-head comparison with its non-deuterated version, [18F]FP-(+)-DTBZ (AV-133), in healthy individuals and PD patients.ResultsThe automated synthesis of D6-[18F]FP-(+)-DTBZ using the SPE method was accomplished in 35 min, yielding a high radiochemical purity (> 99%) and high radiochemical yields (35 ± 5%). The biodistribution and dosimetry study indicated an effective dose of 37.1 ± 7.2 μSv/MBq, with the liver receiving the highest radiation dose (289.6 ± 42.1 μGy/MBq), followed by pancreas (185.2 ± 29.1 μGy/MBq). Brain imaging with D6-[18F]FP-(+)-DTBZ exhibited a significantly increased uptake in VMAT2-rich regions, particularly the striatum. In a head-to-head comparison between [18F]FP-(+)-DTBZ and D6-[18F]FP-(+)-DTBZ, the latter exhibited approximately 15% higher SUVR in the caudate, putamen, and nucleus accumbens. Preliminary studies in PD patients showed a substantial reduction in VMAT2 uptake in the striatum, with the most pronounced decrease observed in the putamen (a 53% decline).ConclusionsD6-[18F]FP-(+)-DTBZ is a safe and improved VMAT2-specific imaging agent, which may be suitable for diagnosing PD by evaluating changes in VMAT2 binding of monoamine neurons in the brain.Trial registration Chinese Clinical Trial Registry, ChiCTR2200057218, Registered 16 August 2021, https://www.chictr.org.cn/bin/project/edit?pid=142725.

Enhancing Gentamicin Antibacterial Activity by Co-Encapsulation with Thymoquinone in Liposomal Formulation

Background and Purpose. Gentamicin (GEN) is a broad-spectrum antibiotic that cannot be prescribed freely because of its toxicity. Thymoquinone (THQ), a phytochemical, has antibacterial, antioxidant, and toxicity-reducing properties. However, its hydrophobicity and light sensitivity make it challenging to utilize. This incited the idea of co-encapsulating GEN and THQ in liposomes (Lipo-GEN-THQ). Method. Lipo-GEN-THQ were characterized using the zeta-potential, dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscope (TEM). The liposomes’ stability was evaluated under different storage and biological conditions. Lipo-GEN-THQ’s efficacy was investigated by the minimum inhibitory/bactericidal concentrations (MICs-MBCs), time–kill curves, and antibiofilm and antiadhesion assays. Bacterial interactions with the empty and GEN-THQ-loaded liposomes were evaluated using TEM. Results. The Lipo-GEN-THQ were spherical, monodispersed, and negatively charged. The Lipo-GEN-THQ were relatively stable and released GEN sustainably over 24 h. The liposomes exhibited significantly higher antibacterial activity than free GEN, as evidenced by the four-fold lower MIC and biofilm eradication in resistant E. coli strain (EC-219). TEM images display how the empty liposomes fused closely to the tested bacteria and how the loaded liposomes caused ultrastructure damage and intracellular component release. An antiadhesion assay showed that the Lipo-GEN-THQ and free GEN (0.125 mg/L) similarly inhibited Escherichia coli (EC-157) adhesion to the A549 cells (68% vs. 64%). Conclusions. The Lipo-THQ-GEN enhanced GEN by combining it with THQ within the liposomes, reducing the effective dose. The reduction in the GEN dose after adding THQ may indirectly reduce the toxicity and aid in developing an enhanced and safer form of GEN.

The effect of radiotherapy, chemotherapy, and immunotherapy on fusion rate in spinal surgery using osteobiologics for patients with metastatic spinal disease: a systematic review.

To evaluate the impact that adjuvant therapies like radiotherapy, chemotherapy, and immunotherapy have on osteobiologic properties and bony regeneration in patients with metastatic spine disease (MSD) undergoing spinal fusion surgery. PubMed and ClinicalTrials.gov searches were performed. MSD patients undergoing fusion surgery with an osteobiologic and radiotherapy, chemotherapy and/or immunotherapy were included. Demographics, primary tumor, surgery, adjuvant treatments, osteobiologic type, fusion rates with scoring criteria, hardware failure, reoperation rates, follow-up, and survival were extracted. 1487 studies were screened, 20 included. 585 patients (464 with MSD) had fusion rates ranging from 17.9 to 100%. In the setting of radiotherapy, fusion rates of 10 studies using autologous bone graft (autograft), 5 studies using allogenic bone graft (allograft), 5 studies using combination autograft/allograft, 4 studies using biomaterial scaffolds (BMS), 3 studies using demineralized bone matrices (DBM), and 1 study using growth factors (GF), were 50-100%, 17.9-100%, 57.8-100%, 52.9-100%, 20-100%, and 100%, respectively. A higher incidence of fusion in patients with autograft or allograft receiving stereotactic body radiotherapy (SBRT) at lower biologically effective doses (BED) and at least 1-month postoperatively was noted. Chemotherapy had no impact on fusion. No studies evaluated the impact of immunotherapy on fusion. SBRT at lower doses given greater than 1-month postoperatively may enhance bony fusion in patients receiving autograft, allograft, or autograft/allograft. Chemotherapy may delay bony fusion without affecting overall fusion rates. Preclinical studies suggest immunotherapy may prevent osteolysis and promote osteogenesis, but no studies have yet evaluated the clinical impact of these findings on spinal fusion. Further research is needed on osteobiologics in bony regeneration in the MSD population.

Quantifying of highly radioactive and radiotoxic polonium-210 intake from cannabis (Cannabis sativa L.): impacts of different smoking and vaporization techniques.

This study investigates the radiation dose that humans receive from naturally occurring uranium-series radionuclides, with a focus on alpha-emitting polonium-210 (210Po), which has a half-life of 138.4days. Polonium is efficiently absorbed by living organisms and is estimated to contribute approximately 7% of the total effective dose from ingested natural internal radiation. The primary source of atmospheric 210Po is the decay of radon-222 (222Rn), which precipitates onto land and water surfaces, including crops. In Cannabis sativa, 210Po accumulates primarily through direct deposition on leaf surfaces and from fertilizers, particularly phosphate fertilizers. This study examined 10 samples of dried hemp (Cannabis sativa L.) legally available in Poland, assessing 210Po concentrations through radiochemical analysis. Various consumption methods were analyzed, including smoking with a glass pipe, a water pipe (bong), a cigarette (joint or spliff), and vaporization. The desorption of 210Po during combustion and vaporization was measured, revealing significant differences based on the method used. Results showed that smoking with a glass pipe resulted in the highest desorption of 210Po (approximately 80%), while water pipe and blunt smoking exhibited lower desorption rates (around 40%). The efficiency of 210Po adsorption in filters varied, with water filters showing about 8% absorption and cellulose filters about 20%. Vaporization results indicated that the desorption of 210Po increased with temperature. These findings underscore the importance of considering the method of consumption when calculating the radiation dose from 210Po, as the differences can significantly impact the accuracy of dose assessments. The study highlights the need for further research to optimize safety guidelines for cannabis consumption in relation to radioactive contaminants.

Treat-to-target fixed dose rituximab retreatment versus fixed interval retreatment with disease activity-guided rituximab dose optimisation for patients with rheumatoid arthritis: study protocol for a multicentre randomised controlled superiority trial focusing on long-term disease impact (RITUXERA)

BackgroundThe optimal retreatment strategy with rituximab for rheumatoid arthritis (RA) remains a point of discussion. Depending on local guidelines, rituximab can either be administered at fixed intervals or when losing disease control, balancing therapeutic effectiveness with drug overexposure. However, treatment based on loss of disease control may significantly affect patients’ lives, provoking uncertainty and potentially leading to progressive joint damage. Moreover, as low-dose rituximab proved to be effective in treating RA while decreasing toxicity, drug exposure may be limited by tapering down rituximab doses guided by disease activity.MethodsRITUXERA is a 104-week open-label multicentre randomised controlled superiority trial. In total, 134 patients with RA treated with rituximab will be 1:1 randomised when in need of retreatment (DAS28-CRP ≥ 3.2 with previous rituximab administration at least 24 weeks earlier) to either a treat-to-target-driven fixed dose retreatment strategy (usual care group) or fixed interval disease-activity guided dose optimisation strategy (experimental group). The usual care group will be retreated with fixed rituximab doses (1 × 1000 mg IV) in case of loss of disease control (DAS28-CRP ≥ 3.2). The experimental group will receive a 24-weekly rituximab treatment while tapering down the dose in a decreasing sequence if DAS28-CRP ≤ 3.2: 1 × 1000 mg IV (maximal dose), 1 × 500 mg IV, and 1 × 200 mg IV (minimal dose). If DAS28-CRP exceeds 3.2 at the six-monthly retreatment, patients will receive and remain on the previous effective dose. Study visits are planned every 12 weeks. Primary outcome is the comparison of longitudinal patient-reported disease impact over 104 weeks, measured with the Rheumatoid Arthritis Impact of Disease (RAID) instrument, analysed using a linear mixed model. Main secondary outcome is the comparison of longitudinal disease activity (DAS28-CRP) over 104 weeks.DiscussionThe RITUXERA trial aims to explore the optimal retreatment strategy with rituximab for RA in terms of long-term patient-reported disease impact, by proposing a fixed interval disease activity-guided dose optimisation strategy as compared to a treat-to-target fixed dose strategy.Trial registrationCTIS 2023–506638-59–01 (registration date: 07 September 2023), ClinicalTrials.gov NCT06003283 (registration date: 17 August 2023).

Factors affecting radiation exposure in patients undergoing endoscopic treatment for urolithiasis.

Imaging techniques, such as computed tomography (CT) and fluoroscopy, are essential for the diagnosis and treatment of urolithiasis. There is increasing concern regarding the cumulative radiation dose associated with medical imaging and its adverse effects. This study aimed to assess radiation exposure in patients undergoing endoscopic management of urolithiasis and to identify factors associated with increased exposure.A retrospective analysis of all consecutive symptomatic urolithiasis cases who underwent endoscopic surgery over a two-year period at a tertiary referral center was performed. The cumulative radiation dose was recorded per stone episode, and the effective dose (ED) then calculated. Multivariable regression analysis was performed to determine the association between ED and patient, stone, and procedural characteristics.Between January 2020 and December 2021, 250 patients underwent endoscopic intervention for urolithiasis; 71% (n = 178) were male with a median age of 48 years (IQR 35-59). The median stone size was 6mm (IQR, 5-8mm) and the median stone volume was 110 mm3 (IQR, 60-206 mm3). Most stones were located in the distal ureter (46%, n = 114). The median ED received per stone episode was 3.99 mSv (IQR 2.9-7 mSv). On multivariable analysis, BMI, number of CT scans performed, CT protocol used, and repeat procedures strongly predicted increased radiation dose (p < 0.01).It is important for urologists to consider the cumulative radiation dosage in patients with urolithiasis. Strategies to minimize exposure, such as avoiding re-imaging, low-dose CTs, and collimation of the region of interest with judicious magnification, should be considered during treatment.

Trypanosoma cruzi infection enhances olfactory response in Triatoma pallidipennis Stål (Hemiptera: Triatominae) to compounds potentially useful for insect control.

In Mexico, Triatoma pallidipennis is a major vector of Trypanosoma cruzi, the causative agent of Chagas disease. Current efforts are focused on developing attractants to control these vectors, using volatile substances derived from vertebrate hosts or compounds known to attract hematophagous insects. However, the efficacy of these compounds in attracting parasite-infected triatomines remains to be evaluated. In this study, we assessed the attractant activity of octenol (1-octen-3-ol), nonanal and a mixture of odorants consisting of ammonium hydroxide, lactic acid and hexanoic acid (in a ratio of 1:0.2:0.4 respectively), at concentrations of 1, 10 and 100 ng on the N3, N4 and N5 nymphal stages of T. pallidipennis, both infected and non-infected with T. cruzi. We also evaluated the synergistic effect of the most effective compounds and doses. All experiments were performed in a laboratory using a Y-type glass olfactometer. We found that both infected and non-infected N3 and N4 nymphs were attracted to low doses of octenol, nonanal and the odorant mixture. Particularly noteworthy was the synergistic effect observed between the odorant mixture and nonanal, which significantly increased attraction of T. cruzi-infected individuals. These findings contribute to the development of baited traps utilising these compounds for monitoring triatomines in epidemiological studies or for mass trapping to control these vectors.

Continuous monitoring of outdoor natural gamma absorbed dose rate in air: a long-term study in Kolkata, West Bengal, India

AbstractThis study contributes to the overarching Indian Environmental Radiation Monitoring Network initiative, concentrating on the continual assessment of the gamma absorbed dose rate in outdoor air attributable to natural gamma radiation in Kolkata, West Bengal, India. Over a span of fourteen years (2011–2024), data were gathered from 32 monitoring sites within the city utilizing permanently installed Geiger-Mueller detector-based environmental radiation monitors. This paper offers an analysis of extensive findings from long-term monitoring efforts. The absorbed gamma dose rate in outdoor air varied among the monitoring sites, ranging from 78 ± 5 to 137 ± 4 nGy h− 1, with a mean value of 107 ± 12 nGy h− 1. The estimated mean annual effective dose due to outdoor natural gamma radiation ranged from 0.10 ± 0.01 to 0.17 ± 0.01 mSv y− 1, with an overall mean of 0.13 ± 0.01 mSv y−1.

Development of a method to use standard hospital gamma cameras as triage whole body monitors in UK emergencies

This paper outlines the process by which a medical gamma camera can be utilised to support assessment of internal radionuclides for the public. While hospital based gamma cameras are able to detect photopeaks, they are often limited to an energy range of 40-540 keV. However, radionuclides with photopeak energies above 540 keV can still be detected as the partial collection of photon energy increases the count rate at lower energies. By combining extensive mathematical modelling with empirical calibration of multiple gamma cameras it is possible to develop a linear correlation between the efficiency of counting point sources and the overall counting efficiency for the camera. Once established, a simple protocol can be used to characterise any gamma camera, using optimal system settings, and hence generate a system efficiency with sufficient accuracy to allow the camera to be used in a triage process to committed effective doses of 2 mSv.&#xD.

The Use of Cone-Beam Computed Tomography (CBCT) Arthrography for Wrist Ligamentous Injuries - A Diagnostic Test Accuracy Meta-analysis.

Background: Diagnosis of ligamentous wrist injuries can be challenging with the absence of dynamic instability on radiographs. Our aim was to evaluate the accuracy of cone-beam computed tomography (CBCT) arthrography in diagnosing scapholunate ligament (SLL), lunotriquetral ligament (LTL) and triangular fibrocartilage complex (TFCC) injuries. Methods: A systematic review and literature search were conducted in compliance with Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) and registered at the International Prospective Register of Systematic Reviews, PROSPERO (CRD42024517655). A mixed-effects logistic regression bivariate model was used to estimate summary sensitivity and specificity, and hierarchical summary receiver operating characteristic (HSROC) curves were constructed to determine diagnostic accuracy of CBCT arthrography. Results: We identified five studies assessing the accuracy of CBCT arthrography against wrist arthrography or intraoperative findings as reference standard. The pooled estimates for sensitivity and specificity of CBCT arthrography was 93% (95% CI 40-100) and 91% (95% CI 81-96) for SLL injuries, 83% (95% CI 37-98) and 64% (95% CI 42-81) for LTL injuries and 78% (95% CI 57-91) and 80% (95% CI 54-93) for TFCC injuries. The area under the curve was 0.91 (95% CI 0.89-0.94), showing an excellent diagnostic accuracy of CBCT arthrography in SLL injuries. CBCT arthrography had an estimated mean effective dose of 3.2 mSv (2.0-4.8). Conclusions: Our study confirms that CBCT arthrography has an excellent diagnostic accuracy for wrist ligamentous injuries with comparably high sensitivity to conventional arthrography and a better specificity. While further studies with more robust methodology are required to support its implementation in clinical practice, our analysis shows that it is a reliable option and has a promising future. Level of Evidence: Level III (Diagnostic).