Safe Exposure Research Articles

Bone Health at Stake: Alarming Prevalence and Predictors of Vitamin D Deficiency in Karachi Children.

Background: Vitamin D insufficiency is a major public health problem for Pakistani children. The purpose of this cross-sectional research was to determine the prevalence and possible correlates of vitamin D insufficiency in young children under the age of five living in Karachi, Pakistan.
 Methods: We analysed data from 400 children aged 0 to 5 years who had vitamin D testing (serum 25-hydroxyvitamin D) at a diagnostic laboratory in Karachi between January and December 2022. Participants' vitamin D levels were classified as adequate (≥30 ng/ml) or insufficient (<30 ng/ml). Logistic regression with robust standard errors adjusted for clustering in the laboratory environment.
 Results: The prevalence of vitamin D insufficiency was disturbingly high at 71.8% (287/400), near national prevalence. Age emerged as a major risk factor, with older children being more likely to be deficient (OR: 1.20 per year increase in age, 95% CI: 1.11-1.30, p 0.001). Winter months increased the incidence of deficit compared to summer (OR: 1.80, 95% CI: 1.21-2.89, p = 0.010). Gender had no significant connection with deficit.
 Conclusions: Our data show that vitamin D insufficiency is a major problem among children in Karachi. To address this public health concern and protect children's health and development, targeted initiatives encouraging safe sun exposure, diversifying diets with vitamin D-rich foods, and investigating fortified staples or regular supplementation are urgently required.

Screening of low-toxic zinc oxide nanomaterials and study the apoptosis mechanism of NSC-34 cells.

With the increasing application of ZnO nanomaterials (ZnO-NMts) in the biomedical field, it is crucial to assess their potential risks to humans and the environment. Therefore, this study aimed to screen for ZnO-NMts with low toxicity and establish safe exposure limits, and investigate their mechanisms of action. The study synthesized 0D ZnO nanoparticles (ZnO NPs) and 3D ZnO nanoflowers (ZnO Nfs) with different morphologies using a hydrothermal approach for comparative research. The ZnO-NMts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Mouse brain neuronal cells (NSC-34) were incubated with ZnO NMts for 6, 12, and 24h, and the cell morphology was observed using TEM. The toxic effects of ZnO Nfs on NSC-34 cells were studied using CCK-8 cell viability detection, reactive oxygen species (ROS) measurement, caspase-3 activity detection, Annexin V-FITC/PI apoptosis assay, and mitochondrial membrane potential (Δφm) measurement. The results of the research showed that ZnO-NMts caused cytoplasmic vacuolization and nuclear pyknosis. After incubating cells with 12.5µgmL-1 ZnO-NMts for 12h, ZnO NRfs exhibited the least toxicity and ROS levels. Additionally, there was a significant increase in caspase-3 activity, depolarization of mitochondrial membrane potential (Δφm), and the highest rate of early apoptosis.This study successfully identified ZnO NRfs with the lowest toxicity and determined the safe exposure limit to be<12.5µgmL-1 (12h). These findings will contribute to the clinical use of ZnO NRfs with low toxicity and provide a foundation for further research on their potential applications in brain disease treatment.

Development and Validation of an Efficient and Safe Loud Music Exposure Paradigm.

The purpose of this study was to develop a time-efficient music exposure and testing paradigm that safely creates temporary cochlear dysfunction that could be used in future temporary threshold shift (TTS) studies. A 30-min audio compilation of pop rock music tracks was created. Adult volunteers with normal hearing were then exposed to this music material monaurally through headphones for 30 min at 97 dBA or 15 min at 100 dBA. Levels were measured from the ear of a manikin and are considered to provide an equivalent daily noise dose based on a 3-dB exchange. We assessed the changes in their hearing, by means of distortion product otoacoustic emission (DPOAE) testing, and standard and extended high-frequency pure-tone audiometry before and after exposure. There were 17 volunteers in total. In the first trial, eight volunteers (four females; Mdnage = 31 years [interquartile range, IQR = 4.25]) were included. Although TTS was observed in all eight participants for at least one frequency, a large variation in affected frequencies was observed. To address this issue, the audio material was further remastered to adjust levels across the different frequency bands. Fourteen adults (nine newly recruited and five from the first trial; seven females; Mdnage = 31 years [IQR = 5]) were exposed to the new material. All but two of 17 participants presented clinically significant TTS or decrease in DPOAE amplitude in at least one frequency. Statistically significant average TTS of 7.43 dB was observed at 6 kHz. There were statistically significant average DPOAE amplitude shifts of -2.55 dB at 4 kHz, -4.97 dB at 6 kHz, and -3.14 dB at 8 kHz. No participant presented permanent threshold shift. A monaural music paradigm was developed and shown to induce statistically significant TTS and DPOAE amplitude shifts, without evidence of permanent loss. This realistic and time-efficient paradigm may be considered a viable option for experimental studies of temporary music-induced hearing loss. https://doi.org/10.23641/asha.25016471.

Consumer experiences and perception with reclosable pharmaceutical child resistant closures in Ghana, West Africa

AbstractChild resistant closures (CRCs) are an effective deterrent in preventing inadvertent poisoning in young children. Nevertheless, investigations since their debut have shown that users in different parts of the world do not embrace this safety package due to their opening mechanism. In this study, consumers who have interacted with pharmaceutical CRCs in Ghana within the West African sub‐region were interrogated to assess their experiences and perception. The assessments centred on consumer attitudes towards using CRCs generally, as well as their understanding of and importance for CRCs, the types that are available, observed cases of unintended medicinal child poisoning, ease of opening and injuries/accidents caused by them. The two observed CRCs used in the region were push and turn and squeeze and turn closures, with the former being the most popular. Regardless of educational level, consumers within the region had little understanding of how CRCs worked and how important they were. Due to their imprecise instructions and unpleasant opening mechanisms, CRCs were generally assessed by consumers as being challenging to open. Consumers unable to open CRCs employed their teeth, knives and sharp objects, resulting in injuries and casualties such as cuts and scratches. To maintain safe containment and limit children's exposure to medications, consumers identified CRCs as their top choice for pharmaceutical packaging. In conclusion, consumers oppose changing the design of CRCs but advocate for better opening instructions and pharmacist education for correct use.

More May Not be Better: Enhanced Spacecraft Shielding May Exacerbate Cognitive Decrements by Increasing Pion Exposures during Deep Space Exploration.

The pervasiveness of deep space radiation remains a confounding factor for the transit of humans through our solar system. Spacecraft shielding both protects astronauts but also contributes to absorbed dose through galactic cosmic ray interactions that produce secondary particles. The resultant biological effects drop to a minimum for aluminum shielding around 20 g/cm2 but increase with additional shielding. The present work evaluates for the first time, the impact of secondary pions on central nervous system functionality. The fractional pion dose emanating from thicker shielded spacecraft regions could contribute up to 10% of the total absorbed radiation dose. New results from the Paul Scherrer Institute have revealed that low dose exposures to 150 MeV positive and negative pions, akin to a Mars mission, result in significant, long-lasting cognitive impairments. These surprising findings emphasize the need to carefully evaluate shielding configurations to optimize safe exposure limits for astronauts during deep space travel.

Comparative study between radiation exposure in common urological procedures

BackgroundFluoroscopy has become essential to urological surgery since advancement of endourology. Fluoroscopy use has increased, placing urologists as well as staff members at risk for occupational radiation exposure and related dangers. This study compared radiation exposure for staff personnel in percutaneous nephrolithotomy (PCNL), ureteroscopy (URS) and extracorporeal shock wave lithotripsy (ESWL). Then, study determined the maximum number of PCNL, URS and ESWL cases that staff members can handle safely each year.ResultsRadiation exposure in PCNL group was higher than URS and ESWL especially for surgeon. Dose of radiation exposure in ESWL for surgeon, assistant and nurse was 2.4 microsievert (μSv), 0.9 μSv and 0.8 μSv, respectively. Dose of radiation exposure in URS for surgeon, assistant and nurse was 18.5 μSv, 14.3 μSv and 13.1 μSv, respectively. Dose of radiation exposure in PCNL for surgeon, assistant and nurse was 73 μSv, 51.3 μSv and 47.6 μSv, respectively.ConclusionIncreased stone size and increased fluoroscopy time were associated with high radiation exposure. PCNL procedure was 8.8 times more likely to exhibit high-dose exposure than other procedures. Urologists can perform: 274 PCNL case, 1081 URS case and 8333 ESWL case per year within safe radiation exposure limits advised by International Commission on Radiation Protection (ICRP).

A digital heliometric device for monitoring sun exposure in cases of hypovitaminosis D: A qualitative analysis of user evaluations from the UAE

BackgroundHypovitaminosis D is a significant health concern in the United Arab Emirates (UAE), particularly among females. Wearable devices designed to encourage safe sun exposure could potentially help individuals achieve and sustain healthy vitamin D levels. ObjectiveThis qualitative, proof-of-concept study aimed to explore the evaluations of Emirati women with hypovitaminosis D regarding the usability and effectiveness of wearing a novel heliometric device to promote and measure safe sun exposure. MethodsNine Emirati women, aged between 19 and 21, adhered to a protocol stipulating that they wear the heliometric device (a wristband) for 10 min daily over one week. Participants were also asked to follow recommended sun exposure guidance. After one week, qualitative evaluations of participant experiences were elicited via open-ended survey questions (an online evaluation form). All participants were also interviewed to elaborate on their written answers. All qualitative data were explored using thematic analysis. ResultsOverall, participants' evaluations of the device were positive. There was broad agreement that the heliometric wristband encouraged compliance with the recommended sun exposure guidance. Other factors that influenced compliance included climatic conditions, religio-cultural clothing norms, and physical activity preferences. Participants were generally favorable about the device's usability and accuracy, although there were some concerns about wearability and connection challenges. Participants suggested improvements in device design and functionality to enhance usability, wearability, and connectivity. The device appeared to help raise awareness and correct misconceptions among participants. ConclusionThe wearable heliometric device was well tolerated, and such devices could be used as an adjunctive technology to help combat hypovitaminosis D by encouraging safe sun behaviors. Further quantitative research using larger samples, longer durations, and control conditions could assess the clinical effectiveness of such devices.

Capsular Management in Hip Arthroscopy: Interportal and T-Capsulotomy, Suspension, and Closure

Capsular management in hip arthroscopy has recently become a popular topic in the literature. Various approaches have been developed around the critical balance between safe and satisfactory exposure while maintaining hip joint stability and the restoration of capsular integrity at the conclusion of the case. Advocates for capsular closure recognize the role of the capsule in providing hip joint stability and aim to reestablish normal hip biomechanics through capsule preservation. Several recent studies have also shown capsular management strategies to influence both clinical outcomes and risk of revision surgery. We present an effective method for capsular management in hip arthroscopy that consistently allows excellent exposure and working space while allowing for facile, anatomic closure.

A narrative review of intraoperative adjuncts and techniques to minimize radiation during complex endovascular aneurysm repair

BackgroundRadiation exposure is a known risk to both patients and providers during endovascular aortic aneurysm repair (EVAR). Complex EVAR procedures, such as fenestrated and branched EVAR, inherently involve longer fluoroscopy times and increased radiation doses. While adhering to the as low as reasonably achievable principles and ensuring appropriate personal protective equipment for all operating room staff remains essential, the use of intraoperative techniques and adjuncts to decrease radiation specifically during complex EVAR is necessary. This review aims to summarize intraoperative radiation reduction techniques to provide valuable insights to vascular surgeons and interventional proceduralists to enhance radiation safety during complex EVAR. MethodsThis review focused on intraoperative techniques and adjuncts that have been used to decrease intraoperative radiation exposure to patients and operators. Published and presented preclinical results, prospective and retrospective study data, and future directions are presented. ResultsWe highlight several intraoperative adjuncts and techniques for reducing radiation exposure during complex EVAR including image fusion, digital zooming, intravascular ultrasound examination, Fiber Optic RealShape (FORS) technology, and robotic navigation systems. Short-term outcomes suggest that these techniques are safe, feasible, and effective and decrease radiation exposure to both patients and operators. ConclusionsDecreasing radiation exposure during complex EVAR remains of critical importance. The presented techniques offer promising avenues for significantly decreasing radiation exposure to both patients and providers while maintaining procedural efficacy during complex EVAR.

A deep-learning approach for identifying prospective chemical hazards

With the aim of helping to set safe exposure limits for the general population, various techniques have been implemented to conduct risk assessments for chemicals and other environmental stressors; however, none of these tools facilitate the identification of completely new chemicals that are likely hazardous and elicit an adverse biological effect. Here, we detail a novel in silico, deep-learning framework that is designed to systematically generate structures for new chemical compounds that are predicted to be chemical hazards. To assess the utility of the framework, we applied the tool to four endpoints related to environmental toxicants and their impacts on human and animal health: (i) toxicity to honeybees, (ii) immunotoxicity, (iii) endocrine disruption via ER-α antagonism, and (iv) mutagenicity. In addition, we characterized the predicted potency of these compounds and examined their structural relationship to existing chemicals of concern. As part of the array of emerging new approach methodologies (NAMs), we anticipate that such a framework will be a significant asset to risk assessors and other environmental scientists when planning and forecasting. Though not in the scope of the present study, we expect that the methodology detailed here could also be useful in the de novo design of more environmentally-friendly industrial chemicals.

Optimization of diffuse Raman spectroscopy for in-vivo quantification of foreign body response in a small animal model.

Diffuse Raman spectroscopy (DRS) allows subsurface molecular analysis of optically turbid samples. Numerical modeling of light propagation was used as a method for improving the design of an DRS instrument to maximize the signal to noise ratio (SNR) while ensuring safe laser exposure parameters required for in-vivo measurements. Experimental validation of the model was performed on both phantom samples and disks implanted postmortem to mimic the typical response to foreign bodies (formation of a fibrotic capsule around an implant). A reduction of laser exposure of over 1500-fold was achieved over previous studies whilst maintaining the same Raman collection rates and reaching the safe power density of 3 mW/mm2. The validation of this approach in a subcutaneous implant in a mouse cadaver showed a further improvement of 1.5-fold SNR, with a thickness limit of detection for the fibrotic layer of 23 µm, under the same acquisition times. In the animal body, a thickness limit of detection of 16 µm was achieved. These results demonstrate the feasibility of numerical model-based optimization for DRS, and that the technique can be improved sufficiently to be used for in-vivo measurement of collagenous capsule formation as a result of the foreign body response in murine models.

A safe and simple exposure and Pringle maneuver in laparoscopic anatomical liver resection of segment 7

BackgroundLaparoscopic access to liver segment 7 (S7) is difficult for deep surgical situations and bleeding control. Herein, our proposed laparoscopic technique for S7 lesions using a self-designed tube method is introduced.MethodsClinical data of patients who underwent laparoscopic anatomical liver resection of S7 (LALR-S7) with the help of our self-designed tube to improve the exposure of S7 and bleeding control in the Second Affiliated Hospital, Third Military Medical University (Army Medical University) from April 2019 to December 2021 were retrospectively analyzed to evaluate feasibility and safety.ResultsNineteen patients were retrospectively reviewed. The mean age was 51.3 ± 10.3 years; mean operation time, 194.5 ± 22.7 min; median blood loss, 160.0 ml (150.0–205.0 ml); and median length of hospital stay, 8.0 days (7.0–9.0 days). There was no case conversion to open surgery. Postoperative pathology revealed all cases of hepatocellular carcinoma (HCC). Free surgical margins were achieved in all patients. No major postoperative complications were observed. Patients with postoperative complications recovered after conservative treatment. During outpatient follow-up examination, no other abnormality was presented. All patients survived without tumor recurrence.ConclusionsThe preliminary clinical effect of our method was safe, reproducible and effective for LALR-S7. Further research is needed due to some limitations of this study.

Exposure to chlorpyrifos and pyrethroid insecticides and symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in preschool children from the Odense Child Cohort

BackgroundAttention Deficit Hyperactivity Disorder (ADHD) is a common childhood psychiatric disorder with severe and lifelong impact on mental health and socioeconomic achievements. Environmental factors may play a role in the increasing incidens rates. Previous studies on associations between prenatal and childhood exposure to organophosphate and pyrethroid insecticides and ADHD symptoms have yielded mixed findings. ObjectivesTo investigate associations between prenatal and childhood exposure to chlorpyrifos and pyrethroids and ADHD symptoms in 5-year-old children from the Odense Child Cohort. MethodsSpot urine samples from pregnant women in gestational week 28 (n = 614) and offspring at 5 years of age (n = 814) were collected and analyzed for the specific metabolite of chlorpyrifos, TCPY (3,5,6-trichloro-2-pyridinol), as well as the generic pyrethroid metabolite, 3-PBA (3-phenoxybenzoic acid). Offspring ADHD symptoms were assessed at age 5 years using the parent reported “ADHD scale” from the “Child Behavior Checklist 1½-5” (n = 1114). Associations between insecticide exposure variables and an ADHD score ≥90th percentile were analyzed using logistic regression for all children and stratified by sex. ResultsMost pregnant women had detectable concentrations of 3-PBA (93%) and TCPY (91%) with median concentrations of 0.20 μg/L and 1.62 μg/L, respectively. In children, 3-PBA and TCPY concentrations were detectable in 88% and 82% of the samples, and the median concentrations were 0.17 and 1.16 μg/L. No statistically significant associations were observed between insecticide metabolites and an ADHD score ≥90th percentile at age 5. ConclusionIn this relatively large Danish birth cohort study with mainly low dietary insecticide exposure, we found no statistically significant associations between prenatal or childhood exposure to chlorpyrifos or pyrethroids, and excess ADHD-symptom load, in 5-year-old children. Prospective studies with multiple urine samples across vulnerable windows of neurodevelopment is warranted to improve assessment of safe exposure levels, which is particularly relevant for pyrethroids, since their use is increasing.

Examining the Perceptions Among Undergraduate Nursing Students Using Virtual Reality in a Community Course: A Mixed-Methods Explanatory Study

ABSTRACT Purpose This study investigated undergraduate nursing students’ perceptions of integrating virtual reality (VR) technology into a community nursing course, specifically home and environmental patient safety assessments. Design This study used a mixed-methods approach with an explanatory design. Methods Participants were recruited from a community health course. The students engaged in a VR simulation involving home visits using the vizHome platform. Quantitative and qualitative data were gathered using the Technology Acceptance Model (TAM) and the System Usability Scale (SUS). Semi-structured interviews were conducted. Quantitative data were collected through Qualtrics and secure Zoom connections for the interviews. The data were analyzed with SPSS and MAXQDA. Findings The results indicated that participants perceived VR as valuable and easy to use for learning home assessment skills. The System Usability Scale (SUS) score revealed room for improvement. Technical limitations were identified as challenges that must be addressed to enhance the user experience. Conclusion Participants acknowledged VR’s potential to supplement traditional learning methods, providing safe and realistic exposure to diverse home environments. While VR was seen as beneficial, it was not considered a replacement for actual home visits in community nursing education. Clinical evidence This study provided clinical teaching evidence on the usability and student perceptions of VR in community courses.

Individual and combined effect of acrylamide, fumitremorgin C and penitrem A on human neuroblastoma SH-SY5Y cells

Acrylamide (AA) is a chemical compound that can be formed in certain foods during high-temperature cooking processes such as frying, baking, and roasting. Exposure to AA has been linked to several neurological effects, including peripheral neuropathy, ataxia, and impaired cognitive function. Penitrem A (PEN A) and Fumitremorgin C (FTC) are toxic mycotoxins produced by certain species of fungi, such as Penicillium Crustosum, Aspergillus Fumigatus and Neosartorya Fischeri. Both mycotoxins are commonly found in contaminated foods and animal feeds and have been linked to several adverse health effects in humans and animals, including the ability to disrupt normal functioning of the nervous system, tremors, seizures, muscle spasms, and convulsions. AA, PEN A, and FTC are all chemical contaminants. Understanding their toxicity and how they may affect human cells can help food safety authorities to establish safe exposure levels for these compounds through food and develop strategies to reduce their presence. The aim of this study was to explore the combined in vitro toxicological effects of AA, PEN A and FTC in SH-SY5Y cells. For this purpose, cells were treated with AA, FTC, and PEN A as an individual and combined treatment. The types of interactions were assessed by the isobologram analysis. The cell cycle was performed by flow cytometry. Additive effect in binary and tertiary combinations was the major effect according to isobologram graphics. Our results demonstrate that PEN A possessed the highest potential in disturbing cell cycle progression by disrupting cell density in G0/G1 phase.

IVIVE-PBPK based new approach methodology for addressing early life toxicity induced by Bisphenol A

Bisphenol A (BPA) is a known endocrine disruptor mimicking natural estrogens with the potential to affect human health, especially during prenatal and postnatal exposure at or below current acceptable daily intake levels. Different adverse effects of BPA are still under investigation, and multiple mechanisms of action remain unexplored. This may be one of the reasons for the continuously changing tolerable daily intake (TDI) of BPA with the emergence of new adverse health effects over time. In addition, translational modelling through in vitro-in vivo extrapolation (IVIVE) can act as prerequisite bridge for translating in-vitro finding into human risk assessment. The objective of this study was to conduct in-vitro experiments and utilize an IVIVE-pregnancy physiologically based pharmacokinetic (P-PBPK) modeling to investigate developmental neurotoxicity and embryotoxicity in humans. The data obtained from human embryonic stem cells-based assays (study conducted between October 2020–2021) were used for the IVIVE-P-PBPK models to obtain the human equivalent doses (HEDs) which were further extrapolated to reference doses (RfDs). The results showed that simulated mean RfDs (μg/kg/day) derived from the HSD3B1 and NFATC2 gene of embryotoxicity and neurodevelopmental toxicity tests, respectively, were 4.94 and 5.18. The simulated RfDs were close to the temporary-tolerable daily intake (t-TDI) recommended by European Food Safety Authority (EFSA) in 2015 (t-TDI: 4 μg/kg·bw) and higher than the TDI of 2023 (0.2 ng/kg·bw). In conclusion, in-vitro toxicogenomics dose-response data combined with PBPK modeling can become a promising alternative new approach methodology (NAM) to support decision-making in chemical risk assessment. Based on the simulated RfDs derived from this NAM, the t-TDI set by EFSA in 2015 may be considered a safe exposure limit for mothers and fetuses at the current BPA intake levels in Chinese mothers. This study provided an animal-free new strategy for NAMs based risk assessment by combining toxicogenomics and computational toxicology.

Interspecies scaling of toxicity reference values in human health versus ecological risk assessments: A critical review.

Risk assessments that focus on anthropogenic chemicals in environmental media-whether considering human health or ecological effects-often rely on toxicity data from experimentally studied species to estimate safe exposures for species that lack similar data. Current default extrapolation approaches used in both human health risk assessments and ecological risk assessments (ERAs) account for differences in body weight between the test organisms and the species of interest, but the two default approaches differ in important ways. Human health risk assessments currently employ a default based on body weight raised to the three-quarters power. Ecological risk assessments for wildlife (i.e., mammals and birds) are typically based directly on body weight, as measured in the test organism and receptor species. This review describes differences in the experimental data underlying these default practices and discusses the many factors that affect interspecies variability in chemical exposures. The interplay of these different factors can lead to substantial departures from default expectations. Alternative methodologies for conducting more accurate interspecies extrapolations in ERAs for wildlife are discussed, including tissue-based toxicity reference values, physiologically based toxicokinetic and/or toxicodynamic modeling, chemical read-across, and a system of categorical defaults based on route of exposure and toxic mode of action. Integr Environ Assess Manag 2024;20:749-764. © 2023 SETAC.

Osteological morphometric analysis of instrumentation safe zones of C1 and C2 vertebra in North Indian population: a multicentric study

Background: The complex anatomy and critical functional role of the C1 and C2 vertebrae necessitate precise understanding of safe zones for instrumentation to mitigate risks during surgical interventions. This study aimed to conduct a comprehensive morphometric analysis to identify and characterize safe zones for instrumentation within C1 and C2 vertebrae. Though there are multiple radiological based studies, actual osteological measurements are not available for North Indian population. Methods: 200 atlas and axis vertebrae were measured within an accuracy of 0.01 mm to ascertain various dimensions, distances and angles to guide safe exposure and instrumentation. To the best of our knowledge this observational morphometric study is first to provide actual osteological measurements in large number of C1 and C2 vertebrae in North Indian population. Results: The morphometric analysis revealed precise measurements of pedicle dimensions, transverse foramen parameters, and distances from key anatomical landmarks within C1 and C2 vertebrae. Safe zones for instrumentation were identified based on these measurements, considering the optimal implant size and trajectory to minimize the risk of neural or vascular damage. Differences between the morphology of North Indian, South Indian and Turkish C1 and C2 morphology was also identified. Conclusions: This study provides critical insights into the morphometric parameters which can be used to identify safe zones for instrumentation within the C1 and C2 vertebrae. The identified safe zones and associated measurements are essential for optimizing surgical strategies, enhancing instrumentation accuracy, and ultimately improving patient outcomes during craniovertebral surgical procedures. Spine Surgeons can utilize this data to tailor surgical approaches and implant placements, promoting safer and more effective interventions in the challenging anatomical region of the craniovertebral junction.

SAT559 Challenges Involved in Managing a Paraplegic Patient with Metastatic Papillary Thyroid Cancer Requiring Radioactive Iodine Therapy

Abstract Disclosure: G. Al-Naqeeb: None. E. Munger: None. P. Veeraraghavan: None. C. Cochran: None. P. Bernaldez: None. P. Wong: None. N. Devaraj: None. T. Fisher: None. K. Lee: None. O. Owoade: None. I. Jones: None. S. Gubbi: None. J. Klubo-Gwiezdzinska: None. Background: High radioactive iodine (RAI) therapy doses utilized for treating thyroid cancer patients require a 24-48-hour radiation isolation period until the total effective dose equivalent exposure (TEDE) to the general population does not exceed 5mSv. We present a unique scenario of a paraplegic patient with metastatic papillary thyroid cancer (PTC) requiring RAI therapy and the radiation precaution strategies implemented by our team to reduce radiation exposure risk to the medical staff.A 69-year-old female with RAI-refractory tall cell-variant PTC (pT4aN1bM1; BRAF V600E pathogenic variant) with pulmonary metastases, paraplegia due to a motor vehicle accident with neurogenic bowel and bladder, was referred to our center for management of PTC. Laboratory data revealed a serum thyroglobulin of 2313 ng/mL (normal=1.6-59.9), and anatomical imaging showed numerous pulmonary nodules that had increased in size and number compared to prior imaging from 6 months ago. Due to disease progression, re-differentiation therapy with dabrafenib was initiated. After 3-months of dabrafenib therapy, a diagnostic thyroid hormone withdrawal-aided 131I scan with dosimetry revealed a significant re-induction of RAI uptake in pulmonary lesions and it was determined that therapy with an RAI dose of 200 mCi would not exceed a safe radiation exposure to the bone marrow of 200 rads. A multi-step mitigation strategy was developed based on a multidisciplinary team meeting and appropriate mock sessions. Stay times were estimated for individuals based on historical TEDE following the care of non-paralyzed patients receiving similarly prescribed activity. To minimize exposure to nursing staff, the patient’s Foley catheter was shielded with lead lining and bowels were emptied the night before RAI with a laxative. For each entry, posted safety sheets were updated with one-foot and one-meter isodose lines and on-contact exposure rates. Two nurses and one radiation safety staff member donned full personal protective equipment (PPE; full body suit, double gloves, booties, face covering) in the staging area and entered via lane one. While nursing provided direct care needs, radiation safety staff emptied the shielded catheter, organized clutter and packaged radioactive waste containers. Upon completion of duties, staff exited via lane two, removed PPE, and performed a full personnel contamination survey in the staging area. The patient successfully underwent RAI therapy with 200 mCi. Six months later the serum thyroglobulin had reduced to 48.4ng/ml with a substantial reduction in pulmonary metastatic tumor burden on imaging studies. Conclusion: Post-RAI therapy care of paralyzed patients during radiation isolation poses a unique challenge to medical staff warranting modifications in routine care practices, which can be achieved safely through optimal planning and enhanced training. Presentation Date: Saturday, June 17, 2023

Human health risk assessment due to mercury use in gold mining areas in the Ecuadorian Andean region

Mining activity drives economic development and has established itself as one of the main industrial spheres globally. However, illegal, and artisanal gold mining, which uses mercury (Hg), is a major source of global pollution. Hg is highly toxic and persistent in the environment, affecting human health and the ecosystem. The objective of this research is to; (a) analyze Hg concentrations in surface waters of nine provinces of the Andean region of Ecuador and compare them with the maximum permissible limits of Ecuadorian regulations, and (b) evaluate the health risk of people exposed to waters with high Hg content through residential and recreational scenarios. In this study, 147 water samples from rivers and streams were analyzed. The results revealed worrying levels of Hg, especially in the provinces of Azuay and Loja where Hg values of up to 0.0913 mg/L and 0.0387 mg/L, respectively, were detected. In addition, it was found that 45% of the samples did not meet the water quality criteria for the preservation of aquatic life, which represents a severe risk to the ecosystem. The probabilistic risk analysis yielded values that exceeded the acceptable exposure limit for adults and children in residential settings in Azuay and Loja, while in the recreational scenario the safe exposure limit was exceeded for both receptors only in the province of Azuay. The elevated presence of Hg in the provinces, mainly in Azuay and Loja, possibly related to illegal gold mining activity, represents a threat to water quality and aquatic life in the Andean region of Ecuador. Children are especially vulnerable, and effective regulation is required to ensure the safety of the population. This study provides valuable information for decision makers regarding the risk associated with Hg exposure in areas of mining activity in the Ecuadorian Andean region. In addition, it can contribute to the development of policies and strategies to control contamination in mining environments and protect human and environmental health in the region.