Dose Monitoring Research Articles

Development and Demonstration of a Wireless Ultraviolet Sensing Network for Dose Monitoring and Operator Safety in Room Disinfection Applications.

The use of mobile ultraviolet-C (UV-C) disinfection devices for the decontamination of surfaces in hospitals and other settings has increased dramatically in recent years. The efficacy of these devices relies on the UV-C dose they deliver to surfaces. This dose is dependent on the room layout, the shadowing, the position of the UV-C source, lamp degradation, humidity and other factors, making it challenging to estimate. Furthermore, since UV-C exposure is regulated, personnel in the room must not be exposed to UV-C doses beyond occupational limits. We proposed a systematic method to monitor the UV-C dose administered to surfaces during a robotic disinfection procedure. This was achieved using a distributed network of wireless UV-C sensors that provide real-time measurements to a robotic platform and operator. These sensors were validated for their linearity and cosine response. To ensure operators could safely remain in the area, a wearable sensor was incorporated to monitor the UV-C exposure of an operator, and it provided an audible warning upon exposure and, if necessary, ceased the UV-C emission from the robot. Enhanced disinfection procedures could then be conducted as items in the room could be rearranged during the procedure to maximise the UV-C fluence delivered to otherwise inaccessible surfaces while allowing UVC disinfection to occur in parallel with traditional cleaning. The system was tested for the terminal disinfection of a hospital ward. During the procedure, the robot was manually positioned in the room by the operator repeatedly, who then used feedback from the sensors to ensure the desired UV-C dose was achieved while also conducting other cleaning tasks. An analysis verified the practicality of this disinfection methodology while highlighting factors which could affect its adoption.

Gallosilicate glass and fiber for radiation detection

AbstractAs ionizing radiation can cause harmful effects to human and electronic devices, accurate dose monitoring plays an important role in fields such as radiotherapy, nuclear industry, and aerospace. Currently, it is still a challenge to fabricate a miniaturized dosimeter that can achieve real‐time monitoring. Here, a gallosilicate glass with potential application in visualization detection of ultraviolet and ionizing radiation, as well as cumulative dose measurement, is presented. Color centers are induced in the glass upon exposure to ultraviolet or ionizing radiation, resulting in a darkening effect. The color change of glass is related to the energy and intensity of incident photons and can be erased by subsequent heat treatment. Electron paramagnetic resonance measurement indicates that the formation of color centers is associated with non‐bridging oxygen hole centers related to gallium. The glass can be fabricated into fiber with perfect core‐cladding structure, which provides an alternative for preparing a new type of high‐sensitivity radiation dosimeter.

Flexible fully organic indirect detector for megaelectronvolts proton beams

A flexible, fully organic detector for proton beams is presented here. The detector operates in the indirect mode and is composed of a polysiloxane-based scintillating layer coupled to an organic phototransistor, that is assessed for flexibility and low-voltage operation (V = −1 V), with a limit of detection of 0.026 Gy min−1. We present a kinetic model able to precisely reproduce the dynamic response of the device under irradiation and to provide further insight into the physical processes controlling it. This detector is designed to target real-time and in-situ dose monitoring during proton therapy and demonstrates mechanical flexibility and low power operation, assessing its potential employment as a personal dosimeter with high comfort and low risk for the patient. The results show how such a proton detector represents a promising tool for real-time particle detection over a large area and irregular surfaces, suitable for many applications, from experimental scientific research to innovative theranostics.

Artificial Intelligence in Continuous Kidney Replacement Therapy.

Artificial Intelligence in Continuous Kidney Replacement Therapy.

Monitoring cone-beam CT radiation dose levels in a University Hospital.

To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation mode, and patient age. An integrated dose monitoring tool was used to collect radiation exposure data [type of CBCT unit, dose-area product (DAP), FOV size, and operation mode] and patient demographic information (age, referral department) performed on a 3D Accuitomo 170 and a Newtom VGI EVO unit. Effective dose conversion factors were calculated and implemented into the dose monitoring system. For each CBCT unit, the frequency of examinations, clinical indications, and effective dose levels were obtained for different age and FOV groups, and operation modes. A total of 5163 CBCT examinations were analyzed. Surgical planning and follow-up were the most frequent clinical indications. For the standard operation mode, effective doses ranged from 35.1 to 300 µSv and 9.26-117 µSv using 3D Accuitomo 170 and Newtom VGI EVO, respectively. In general, effective doses decreased with increasing age and FOV size reduction. Effective dose levels varied notably between systems and operation modes.Operation mode selection and FOV size were indication-oriented, with larger FOV sizes election serving surgical planning and follow-up. Seeing the influence of FOV size on effective dose levels, manufacturers could be advised to move toward patient-specific collimation and dynamic FOV selection. Systematically monitoring patient doses could be recommended for steering future CBCT optimization.

Water luminescence imaging for visualization of therapeutic effects of proton therapy and radiosensitizers

Chemoradiotherapy, which combines chemotherapy and radiotherapy, has recently gained popularity. However, some chemoradiotherapy drugs have yet to be used in clinical practice because biocompatibility and the mechanism of their therapeutic effects are not clearly understood. Therefore, we focused on the luminescence imaging proposed by Yamamoto et al. (2015); Yamamoto (2021). It is a method for observing luminescence that occurs even under radiation with energy below the Cherenkov threshold. Moreover, the emission profiles were consistent with the dose distribution (Yamamoto, 2021; Yabe et al., 2018). We examined the luminescence mechanism of water irradiated with proton beams to determine whether it can be used to monitor the therapeutic effect of drugs that are going to be used for chemoradiotherapy. We succeeded in obtaining images and spectra of luminescence, and the results suggested that water luminescence may have complex structures. These findings may provide not only a new step toward understanding physical and chemical phenomena, but also the sensitization effect depends on drugs that occurs when water is irradiated with proton beams. • We succeeded in obtaining images and spectra of radioluminescence, which has potential for application as a new radiation dose monitor. • The results suggested that water luminescence may have complex structures. • These findings may provide not only a new step toward understanding physical and chemical phenomena that occurs when water is irradiated with proton beams.

A survey of critical care pharmacists on venous thromboembolism prophylaxis dosing practices with enoxaparin in adult trauma patients

AbstractEnoxaparin is the preferred treatment for venous thromboembolism (VTE) prophylaxis in trauma patients, but timing of initiation, optimal dosing, and therapeutic drug monitoring remain controversial. The objective of this study was to evaluate enoxaparin VTE prophylaxis practices in adult trauma patients across trauma centers in the United States and compare results to current guideline recommendations. An online survey designed by the study investigators was sent to pharmacist members of the American College of Clinical Pharmacy (ACCP) Critical Care Practice Research Network (PRN) and residency directors of institutions with accredited Critical Care Pharmacy Residency programs in the fall of 2021. This survey queried pharmacists' self‐reported practices regarding enoxaparin dosing and monitoring in trauma patients. One hundred five responses were collected with an estimated response rate of 5.3%. Most respondents reported using a standard enoxaparin dose of 30 mg subcutaneously (SUBQ) every 12 h (67%; 70/104) in trauma patients with normal renal function and higher initial dosing for obese trauma patients (75%; 78/104). The most common body mass index (BMI) threshold for dose adjustments in obesity was a BMI ≥40 kg/m2; whereas 100 kg or more was commonly reported for a weight threshold. Multiple alternative enoxaparin dosing regimens were reported for obese and overweight patients. Of respondents who monitor anti‐Factor Xa (anti‐Xa) levels, 84% (61/73) reported monitoring peak levels with 47% (29/61) targeting a peak anti‐Xa goal of 0.2–0.4 units/ml. Seventy‐five percent (51/68) of respondents who adjust enoxaparin dosing based on anti‐Xa level monitoring reported adjusting doses by increments of 10 mg SUBQ every 12 h, and 41% (28/68) indicated having a pharmacist‐driven protocol for dose adjustments. Significant variation exists in enoxaparin dosing and monitoring strategies for VTE prophylaxis. Consensus among clinical practice guidelines is needed to standardize practice nationally.

Characterization of Lab-on-Fiber-based dosimeters in ultra-high dose radiation fields

Next generation High Energy Physics (HEP) accelerators will require new devices and technologies capable of operating in extreme environments characterized by ultra-high radiation doses up to the MGy levels. To this aim, we report on an innovative Lab-On-Fiber (LOF) probe for the real-time dose monitoring. The proposed platform is based on a metallo-dielectric nanostructured grating made of gold and poly(methyl methacrylate) (PMMA) patterned on the termination of single mode fibers. The nanostructure has been judiciously designed to support a plasmonic resonance in the reflection spectrum occurring at near infrared wavelengths. Electron beam lithography was used for the fabrication of two LOF prototypes, which in turn, were exposed to X-rays with a total dose of 2.02 MGy and a dose rate of 88 kGy/h. Reflection spectra acquired during the irradiation revealed a clear dependence of the LOF resonance wavelength and depth on the absorbed dose, confirming the outcomes of our previous proton campaign. Morphological characterization of the irradiated samples showed that the main radiation induced effect is the reduction of the PMMA thickness (ranging between 26 % and 40 %), which in turn strongly affects the resonance behavior. Quantitative morphological measurements have been used to achieve a fair and objective correlation with our numerical modelling. Moreover, we investigated the effect of ultra-high doses of several radiation types, including X-rays, electrons and protons, on the thickness of PMMA nanolayers deposited on planar substrates. Experimental results revealed that the amount of absorbed dose (1.9–16.06 MGy) is the main parameter affecting the PMMA relative compaction (9.5–59.1 %), while the influence of the radiation type, dose rate and initial PMMA thickness can be considered negligible. Overall, these results pave the way to the development of radiation type independent PMMA assisted LOF dosimeters operating at MGy doses for the radiation monitoring in future HEP experiments.

Japanese patients need slower, personalized clozapine titrations: A comment on the case described by Kikuchi et al.

Japanese patients need slower, personalized clozapine titrations: A comment on the case described by Kikuchi et al.

Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Children Aged 5-11 Years - United States, October 12-January 1, 2023.

On October 12, 2022, the Food and Drug Administration (FDA) issued Emergency Use Authorizations (EUAs) for bivalent (mRNA encoding the spike protein from the SARS-CoV-2 ancestral strain and BA.4/BA.5 Omicron variants) formulations of Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines for use as a single booster dose ≥2 months after completion of primary series or monovalent booster vaccination for children aged 5-11 years (Pfizer-BioNTech) and 6-17 years (Moderna); on December 8, 2022, FDA amended the EUAs to include children aged ≥6 months (1,2). The Advisory Committee on Immunization Practices (ACIP) recommends that all persons aged ≥6 months receive an age-appropriate bivalent mRNA booster dose (3). The safety of bivalent mRNA booster doses among persons aged ≥12 years has previously been described (4). To characterize the safety of bivalent mRNA booster doses among children aged 5-11 years after receipt of bivalent Pfizer-BioNTech and Moderna booster doses, CDC reviewed adverse events and health impacts reported to v-safe,* a voluntary, smartphone-based U.S. safety surveillance system established by CDC to monitor adverse events after COVID-19 vaccination, and to the Vaccine Adverse Event Reporting System (VAERS), a U.S. passive vaccine safety surveillance system co-managed by CDC and FDA† (5). During October 12-January 1, 2023, a total of 861,251 children aged 5-11 years received a bivalent Pfizer-BioNTech booster, and 92,108 children aged 6-11 years received a bivalent Moderna booster.§ Among 3,259 children aged 5-11 years registered in v-safe who received a bivalent booster dose, local (68.7%) and systemic reactions (49.5%) were commonly reported in the week after vaccination. Approximately 99.8% of reports to VAERS for children aged 5-11 years after bivalent booster vaccination were nonserious. There were no reports of myocarditis or death after bivalent booster vaccination. Eighty-four percent of VAERS reports were related to vaccination errors, 90.5% of which did not list an adverse health event. Local and systemic reactions reported after receipt of a bivalent booster dose are consistent with those reported after a monovalent booster dose; serious adverse events are rare. Vaccine providers should provide this information when counseling parents or guardians about bivalent booster vaccination. Preliminary safety findings from the first 11 weeks of bivalent booster vaccination among children aged 5-11 years are reassuring. Compared with the low risk of serious health effects after mRNA COVID-19 vaccination, the health effects of SARS-CoV-2 infection include death and serious long-term sequalae (6). ACIP recommends that all persons aged ≥6 months receive an age-appropriate bivalent mRNA booster dose ≥2 months after completion of a COVID-19 primary series or receipt of a monovalent booster dose.¶.

A spectroscopic and imaging gamma-detector prototype towards dose monitoring in BNCT

We report the performances of a compact gamma-ray detection prototype, based on a 2” LaBr3 scintillator crystal coupled to a matrix of 64 SiPMs, designed as a single unit for a future SPECT system for dose monitoring in BNCT. The aim of the module is to detect the 478 keV gamma rays emitted by the boron neutron capture reactions, in order to map the 10B distribution in the patient. The spectroscopic capabilities of the module have been validated by irradiating borated vials with thermal neutrons fluxes in the order of 1 × 105 n/cm2/s. The good energy resolution of the detector (2.7% at 662 keV) has allowed to resolve the boron neutron capture photopeak, achieving excellent linear correlation between the number of detected events at 478 keV and the boron concentration in the vials irradiated. Preliminary imaging results based on a Convolutional Neural Network and obtained by irradiating a 5 cm × 5 cm × 2 cm square crystal with a 1 mm collimated 137Cs source (662 keV) are also reported.

Current and Future Therapeutic Approaches of Exocrine Pancreatic Insufficiency in Children with Cystic Fibrosis in the Era of Personalized Medicine.

This review presents current updates of pancreatic enzyme replacement therapy in children with cystic fibrosis based on literature published in the last decade and some special considerations regarding pancreatic enzyme replacement therapy in the era of new therapies, such as cystic fibrosis transmembrane conductance regulator modulator therapies. Few articles evaluate the efficacy of pancreatic enzyme replacement therapy in the pediatric population, and most studies also included children and adults with cystic fibrosis. Approximately 85% of cystic fibrosis patients have exocrine pancreatic insufficiency and need pancreatic enzyme replacement therapy. Fecal elastase is the most commonly used diagnostic test for exocrine pancreatic insufficiency, although this value can fluctuate over time. While it is used as a diagnostic test, it cannot be used for monitoring the effectiveness of pancreatic enzyme replacement therapy and for adjusting doses. Pancreatic enzyme replacement therapy, the actual treatment for exocrine pancreatic insufficiency, is essential in children with cystic fibrosis to prevent malabsorption and malnutrition and needs to be urgently initiated. This therapy presents many considerations for physicians, patients, and their families, including types and timing of administration, dose monitoring, and therapy failures. Based on clinical trials, pancreatic enzyme replacement therapy is considered effective and well-tolerated in children with cystic fibrosis. An important key point in cystic fibrosis treatment is the recent hypothesis that cystic fibrosis transmembrane conductance regulator modulators could improve pancreatic function, further studies being essential. Pancreatic enzyme replacement therapy is addressed a complication of the disease (exocrine pancreatic insufficiency), while modulators target the defective cystic fibrosis transmembrane conductance regulator protein. Exocrine pancreatic insufficiency in cystic fibrosis remains an active area of research in this era of cystic fibrosis transmembrane conductance regulator modulator therapies. This new therapy could represent an example of personalized medicine in cystic fibrosis patients, with each class of modulators being addressed to patients with specific genetic mutations.

Extremity exposure of nuclear medicine workers: results from an EANM and EURADOS survey.

Extremity exposure during the handling of unsealed radioactive sources is a matter of concern for nuclear medicine workers. Next to 99mTc and 18F, other radiopharmaceuticals have seen an increase in their use over the last decade. However, limited information on their impact on extremity dose is available. This study aimed to gain insight into the status of extremity exposure and dose monitoring in Europe. A survey was conducted at the end of 2020 among the European Association of Nuclear Medicine community. It contained 24 questions considering department characteristics, worker tasks, dosimeter use, typical worker extremity dose, department workload for selected radionuclides (99mTc, 18F, 68Ga, 177Lu, 90Y) and protective measures. A total of 106 replies were received, 92% of which were from Europe. About half of the respondents were from academic hospitals. Ninety-nine departments implement extremity dose monitoring for a total of 1335 workers. Most workers (95%) wear a ring dosimeter, generally on the non-dominant hand, and 44% on the index finger. Monthly doses were generally low (median values at different ring position: 0.4-1.8 mSv), although higher doses were reported (20.8-38.8 mSv). About 1/3 of workers performed the full task range (preparation, dispensing, and administration). Administration is associated with significantly lower extremity doses. Interestingly, no correlation between department workload and collective dose was found. The adoption of vial and syringe shielding, as well as distance tools, was common. The workers dispensing 99mTc without syringe shielding or PET nuclides without automated system received a significantly higher dose. Handling 68Ga, 177Lu and 90Y did not appear to have an impact on the reported doses. Protective measures play a significant role in lowering extremity doses, while department workload and more recently introduced radionuclides seem not to be major dose determinants.

Monitoring of annual effective dose (AED) in surface soils of Ahero rice fields, Kenya

Monitoring of annual effective dose (AED) in surface soils of Ahero rice fields, Kenya

The time profile of relativistic solar particle events as observed by neutron monitors

The most energetic particles accelerated in solar eruptive events are protons and nuclei with energies that may reach a few tens of GeV. They can be detected on the Earth through the secondaries they produce when interacting with the atmosphere. Solar energetic particle events where this happens are called Ground-Level Enhancements (GLEs). Their study is relevant on the one hand because the high particle energies pose particularly strong challenges to the understanding of the acceleration processes. On the other hand, the secondary particles constitute a source of radiation in the atmosphere that may temporarily exceed the permanent dose rate from galactic cosmic rays. This makes the monitoring of radiation doses received by aircrew from GLEs one issue of space weather services for civil aviation. This study addresses the time profiles of GLEs, in the search for commonalities that can be used to constrain models of acceleration and propagation and to forecast the evolution of an ongoing event. We investigate historical GLEs (1971–2012) with the worldwide network of neutron monitors, comparing the rise and the decay as observed by the neutron monitor with the strongest response. The sample comprises 23 events. We evaluate statistical correlations between rise time and decay time inferred from fits to the time profiles and compute a normalised median GLE time profile. An empirical correlation reported in earlier work between the observed rise times and decay times of the neutron monitor count rate profiles is confirmed. We find indications of a statistical relationship between the rise times and the parent eruptive activity. We discuss ideas on the mechanisms behind the correlation of rise and decay times and on its usefulness for space weather services.

Monitoring of annual effective dose (AED) in surface soils of Ahero rice fields, Kenya

Monitoring of annual effective dose (AED) in surface soils of Ahero rice fields, Kenya

Impact of a Pharmacist-Managed Outpatient Parenteral Antimicrobial Therapy (OPAT) Service on Cost Savings and Clinical Outcomes at an Academic Medical Center.

Outpatient antimicrobial therapy (OPAT) is managed by a variety of teams, but primarily through an infectious disease clinic. At our medical center, OPAT monitoring is performed telephonically by pharmacists through a collaborative practice agreement under the supervision of an infectious disease physician. The effect of telephonic monitoring of OPAT by pharmacists on patient outcomes is unknown. This retrospective cohort study was conducted between July 2017 and July 2018 at a 350-bed academic medical center and included adult patients discharged home on IV antibiotics or oral linezolid. The experimental group comprised patients discharged with a consultation for the OPAT management program, whereas the control group comprised patients discharged home without a consultation. The primary outcome was 30-day readmission. In total, 399 patients were included: 243 patients in the OPAT management program group and 156 patients in the control group. The 30-day readmission rates were similar in each cohort (20% vs 19%; P = .8193); however, the 30-day readmission rates were lower in the OPAT management program for patients discharged on vancomycin (19.4% vs 39.1%; P = .004). We did not find a difference in 30-day readmissions between patients receiving pharmacy-driven OPAT management services and those who did not. Patients receiving vancomycin via OPAT had lower 30-day readmissions when included in the pharmacist-driven OPAT management program. Institutions with limited resources may consider reserving OPAT management services for patients receiving antimicrobials that require pharmacokinetic dosing and/or close monitoring.

Pharmacological Monitoring of Capecitabine in a Gastric Cancer Patient with Hyperbilirubinemia

Objective: To examine therapeutic drug monitoring in managing hyperbilirubinemia caused by capecitabine in patients with gastric adenocarcinoma with extensive liver metastases. Results: The initial liver function tests showed an elevation of transaminases (aspartate amino transferase 615 UI/l, alanine aminotransferase 385.9 UI/l), hyperbilirubinemia (total bilirubin at 246.1 μmol/l), and alkaline phosphatase at 694.6 UI/l. We initiated capecitabine based combination chemotherapy, and the clinical pharmacist conducted a full-course medication monitoring of the patient’s treatment including design of individualized dosing regimens and monitoring of bilirubin, infection, cancer pain, parenteral nutrition support and adverse events. After 21 days of supervision by clinical pharmacist and clinicians, the patient’s bilirubin and transaminase decreased progressively, with aspartate aminotransferase, total bilirubin and alkaline phosphatase falling back to 57 UI/l, 69.8 μmol/l, 307.2 UI/l, respectively. The patient’s condition improved significantly at the time of discharge, with the jaundice subsided, and the bloating relieved. Conclusion: Due to adverse reactions, capecitabine requires medication monitoring during use. The relationship between effectiveness and adverse effects is controversial. Adverse reactions should not be the sole criterion for the use of drugs. Clinical pharmacists can improve the safety and effectiveness of patients’ medications and promote rational drug use by monitoring patients, which may be useful to help the doctors identify the high-risk patients for taking efficient treatment strategy decisions.

Significance of therapeutic dose monitoring of busulfan and targeted dose adjustment in transplantation

ブスルファンは造血細胞移植の前処置として広く用いられているが，体内動態には個体差が大きいことが知られており，血中濃度の過剰・過少のいずれも移植の転帰に悪影響をもたらしうる。この対策として，ブスルファンの薬物濃度モニタリングに基づいた用量調整が行われる。特に血中濃度が移植成績に直結することが示されている疾患に移植を行う場合や，小児患者に移植を実施する場合はその必要性が高い。また，ブスルファンを前処置に用いる臨床試験では，体重あたりの固定用量ではなく，標的とする血中濃度で表記されることが多くなっている。臨床試験の成果を受けて標準治療が確立した場合には，その成績を実臨床で再現するためにも血中濃度測定による用量調整が必要となる。より安全かつ有効な造血細胞移植を実施するためにも，ブスルファンの血中濃度測定が広くなされるような体制の整備が望まれる。

Development of a X-ray Exposure Dose Control Tool for CT Examination by Using Spreadsheet Software

We developed X-ray dose monitoring and optimization software for computed tomography (CT) by using a spreadsheet software. The analysis was carried out on 1,212 patients using 2,128 CT examinations at our institution, in the period of April 2020 to April 2022. These cases were extracted in the limitation of patient's weight in the range of 50 to 70 kg. The individual radiation report, including CTDIvol and DLP, on the console displayed by a CT system was used and manually transferred to our software. The X-ray dose distribution was evaluated by using a boxplot chart and a scatter plot, and the data were referred to Japan DRLs 2020 (National Diagnostic Reference Levels in Japan 2020). Almost all patient's doses in our institution were distributed in the acceptable ranges in comparison with the Japan DRLs 2020. Neither extremely high nor low dose data were recorded. However, seven cases recorded outlier dose values. Three cases were caused by errors during manually inputting the data. Four from seven cases were explored the reason to record outlier dose values. Our software on a spreadsheet software worked well to explore the CT dose data, such as CTDIvol and DLP. Our software was able to find cases that were recorded as outlier dose values, but their values were not extremely high/low values. The cautionary notice of either high or low dose, as a function of our software, will be able to keep our patient's CT dose in the universal-standard "justification and optimization" level.