Patient-specific Effective Dose Estimation from Dose-Length Product in Lung Computed Tomography Using Monte Carlo Simulation.

Background: Computed tomography (CT) imaging has a large portion in the dose of patients from radiological procedures; therefore, accurate calculation of radiation risk estimation in this modality is inevitable. In this study, a method for determining the patient-specific effective dose using the dose-length product (DLP) index in lung CT scan using Monte Carlo (MC) simulation is introduced. Methods: EGSnrc/BEAMnrc MC code was used to simulate a CT scanner. The DOSxyznrc simulation code was used to simulate a specific voxelized phantom from the patient's lungs and irradiate it according to X-ray parameter of routing lung CT scan, and dose delivered to thorax organs was calculated. Three types of phantoms were simulated according to three different body habits (slim, standard, and fat patients) in two groups of men and women. A factor was used to convert the relative dose per particle in MC code to the absolute dose. The dose was calculated in all lung organs, and the effective dose was calculated for all three groups of patient body habits. DLP index and volume CT dose index (CTDIvol) were extracted from the patient's dose report in the CT scanner. The DLP to effective dose conversion factor (k-factor) for patients with different body habitus was calculated. Results: Lung radiation dose in slim, standard, and fat patients in men was 0.164, 0.103, and 0.078 mGy/mAs and in women was 0.164, 0.105, and 0.079 mGy/mAs, respectively. The k-factor in the group of slim patients, especially in women, was higher than in other groups. Conclusions: CT scan dose indexes for slim patients are reported to be underestimated in studies. The dose report in CT scan systems should be modified in proportion to the patient's body habitus, to accurately estimate the radiation risk.

Dosimetry of [64Cu]FBP8: a fibrin-binding PET probe.

Purpose: This study presents the biodistribution, clearance and dosimetry estimates of [64Cu]Fibrin Binding Probe #8 ([64Cu]FBP8) in healthy subjects. Procedures: This prospective study included 8 healthy subjects to evaluate biodistribution, safety and dosimetry estimates of [64Cu]FBP8, a fibrin-binding positron emission tomography (PET) probe. All subjects underwent up to 3 sessions of PET/Magnetic Resonance Imaging (PET/MRI) 0-2 hours, 4h and 24h post injection. Dosimetry estimates were obtained using OLINDA 2.2 software. Results: Subjects were injected with ~400 MBq of [64Cu]FBP8. Subjects did not experience adverse effects due to the injection of the probe. [64Cu]FBP8 PET images demonstrated fast blood clearance (half-life = 67 min) and renal excretion of the probe, showing low background signal across the body. The organs with the higher doses were: the urinary bladder (0.075 vs. 0.091 mGy/MBq for males and females, respectively); the kidneys (0.050 vs. 0.056 mGy/MBq respectively); and the liver (0.027 vs. 0.035 mGy/MBq respectively). The combined mean effective dose for males and females was 0.016 ± 0.0029 mSv/MBq, lower than the widely used [18F]fluorodeoxyglucose ([18F]FDG, 0.020mSv/MBq). Conclusions: This study demonstrates the following properties of the [64Cu]FBP8 probe: low dosimetry estimates; fast blood clearance and renal excretion; low background signal; and whole-body acquisition within 20 minutes in a single session. These properties provide the basis for [64Cu]FBP8 to be an excellent candidate for whole-body non-invasive imaging of fibrin, an important driver/feature in many cardiovascular, oncological and neurological conditions.

Analysis of dose distribution around a computed tomography scanner in terms of exposure to scattered ionizing radiation of caregivers of pediatric patients.

OBJECTIVES: During computed tomography (CT), a large amount of ionizing radiation is emitted to ensure high quality of the obtained radiological image. This study measured the dose distribution around the CT scanner and the exposure of people staying near the CT scanner during the examination. MATERIAL AND METHODS: The measurements used an anthropomorphic phantom to assess human exposure to ionizing radiation. The probability of inducing leukemia and other cancers as a result of absorbing doses recorded around the CT device was also calculated. RESULTS: The highest exposure to scattered radiation in the proximity of the CT scanner is recorded at the gantry of the tomograph, i.e., 55.7 µGy, and the lowest, below lower detection limit of 6 µGy at the end of the diagnostic table. The whole-body detector placed on the anthropomorphic phantom located at the diagnostic table right next to the CT gantry recorded 59.5 µSv and at the end of the table 1.5 µSv. The average doses to the lenses in these locations were: 32.1 µSv and 2.9 µSv, respectively. CONCLUSIONS: The probability of induction of leukemia or other types of cancer is low, but the need for people to stay in the examination room during a CT examination should be limited to the necessary minimum. Int J Occup Med Environ Health. 2024;37(3).

A systematic review comparing the effective radiation dose of musculoskeletal cone beam computed tomography to other diagnostic imaging modalities.

PURPOSE: Cone-Beam CT (CBCT) is well established in orofacial diagnostic imaging and is currently expanding into musculoskeletal applications. This systematic review sought to update the knowledge base on radiation dose comparisons between imaging modalities in MSK imaging and consider how research studies have reported dose measures. METHODS: This review utilised a database search and an online literature tool. Studies with potential relevance were screened then before full text review, each performed by two independent reviewers, with a third independent reviewer available for conflicts. Data was extracted using a bespoke tool created within the literature tool. RESULTS: 21 studies were included in the review which compared CBCT with MSCT (13), conventional radiography (1), or both (7). 19 studies concluded that CBCT provided a reduced radiation dose when compared with MSCT: the factor of reduction ranging from 1.71 to 50 with an average of 12. Studies comparing CBCT to DR found DR to have an average dose reduction of 4.55. CONCLUSIONS: The claims that CBCT produces a lower radiation dose than MSCT is borne out with most studies confirming doses less than half that of MSCT. Fewer studies include DR as a comparator but confirm that CBCT results in a higher effective dose on average, with scope for CBCT to provide an equivalent radiation dose. This review highlighted a need for consistency in methodology when conducting studies which compare radiation dose across different technologies. Potential solutions lie outside the scope of this review, likely requiring multi-discipline approach to ensure a cohesive outcome.

Radiological impact of 226Ra, 232Th and 40K in fodders from Penang, Malaysia.

The plant acts as an important route for the transfer of radionuclides from the soil to animals, leading to the transfer of radiation to human food products such as beef and milk. Therefore, the level of radioactivity in fodder plays a crucial role in deciding whether cattle may be allowed to graze in a certain area. In this study, the activities of 226Ra, 232Th and 40K were measured via gamma-ray spectrometry on different fodder samples, including napier leaves, rice straw, corn stalks, guinea grass, mixed pasture, palm oil leaves and palm kernel collected from Penang, Malaysia. Theoretical calculations were also conducted to estimate the levels of these radionuclides in caw's products (beef and milk), as well as their potential radiological impact on local consumers. On average, the annual effective dose due to ingestion of radionuclides in milk was 11.39 µSv y-1, whereas in beef it was 5.63 µSv y-1. These values are significantly lower than the worldwide average of 290 µSv y-1. Research confirmed that farmers' usage of the aforementioned feeds did not cause any radiation-related health risks.

Ensuring radiation safety: Evaluating dose and compliance among medical staff at King Faisal Medical Complex, Saudi Arabia.

BACKGROUND: Radiation is an integral part of routine medical practice, but it carries a risk to the health of medical staff. Hence, it should be assessed periodically. The study's goal was to quantify the levels of radiation exposure for medical staff at King Faisal Medical Complex (KFMC), Taif City Saudi Arabia, and to assess their radiation protective procedures in practice. METHODS: The study looked at the thermoluminescence dosimeters (TLDs) records of 50 medical professionals who were exposed to radiation while working at KFMC from 2019 to 2020 in Taif city, Saudi Arabia. In Riyadh, radiation exposure is read from skin TLDs using Harshaw model 6600 plus detectors. The Excel software was utilized to process the obtained data for calculating effective doses. A questionnaire was also distributed to the medical staff to assess their radiation protection procedures. The Statistical Package for Social Sciences (SPSS) program version 23 was used to analyze the obtained data. RESULTS: The mean annual effective doses of the medical staff in 2019 and 2020 were determined to be 1.14 mSv and 1.4645 mSv, respectively, with no significant difference in effective doses between males and females in either year. The socio-demographic features of the medical personnel were examined, and the findings revealed that the majority of participants were male radiological technologists. The rate of adherence to radiation protection techniques was 68%, with a normally distributed dispersal. The amount of adherence varied significantly depending on nationality, occupation, and academic qualification. CONCLUSION: According to the research, the mean annual effective dosage for medical professionals at KFMC was significantly below the recommended level, indicating satisfactory compliance with the ALARA radiation safety concept.

ED50 and ED95 of Remimazolam Tosilate Combined with Different Doses of Fentanyl in Elderly Patients for Painless Gastroscopy.

Background: The novel short-acting benzodiazepine drug, remimazolam tosilate, has been employed for sedation during endoscopic procedures. The optimal loading dosage of remimazolam tosilate in gastroscopy for elderly patients when co-administered with fentanyl remains unclear. Therefore, the primary objective of our research was to ascertain the median effective dose (ED50) and the 95% effective dose (ED95) of remimazolam tosilate in combination with various fentanyl dosages for elderly patients undergoing painless gastroscopy. Methods: Seventy-five patients aged ≥65 years and American Society of Anesthesiologists (ASA) class I-III were recruited to undergo elective painless gastroscopy. All patients were randomized assigned to group F1, group F2, and group F3, and were injected intravenously with different doses of fentanyl (0.5 ug/kg, 1 ug/kg, and 1.5 ug/kg) 3 minutes prior to the administration of remimazolam tosilate, respectively. The initial preset dose of remimazolam tosilate was 0.3 mg/kg in group F1, 0.2 mg/kg in group F2, 0.15 mg/kg in group F3. The dose gradient was 0.02 mg/kg per group according to the up-and-down sequential method. Probibt regression model was employed to determine the ED50 and ED95 of remimazolam tosilate. Results: The ED50 of remimazolam tosilate in group F3 was lower than that in group F1 and F2 (0.095 [0.088-0.108] mg/kg vs 0.162 [0.153-0.171] mg/kg; 0.258 [0.249-0.266] mg/kg, p < 0.05). The ED95 of remimazolam tosilate was 0.272 mg/kg (95% CI: 0.264-0.295 mg/kg) in group F1, 0.175 mg/kg (95% CI: 0.167-0.200 mg/kg) in group F2 and 0.109 mg/kg (95% CI: 0.101-0.135 mg/kg) in group F3. The total dosage of remimazolam tosilate decreased gradually with the increasing of fentanyl (p < 0.001). The frequency of injection pain was higher in group F1 compared to groups F2 and F3 (p < 0.05). The patients in group F3 had a lower incidence of hypotension than in groups F1 and F2 (p < 0.05). There was no respiratory depression, intraoperative consciousness, dizziness or delirium in the three groups. Conclusion: The concurrent use of fentanyl reduces the dosage of remimazolam tosilate required for sedative gastroscopy in elderly patients in a dose-dependent manner. Moreover, 1.5 ug/kg fentanyl combined with remimazolam tosilate may reduce the incidence of hypotension and injection pain. These findings should be confirmed in a large-scale study.

Comparing Radiation Doses in CBCT and Medical CT Imaging for Dental Applications.

Background: Dental imaging plays a crucial role in diagnosis and treatment planning, with cone-beam computed tomography (CBCT) and medical computed tomography (CT) being two common modalities. This study aims to compare the radiation doses associated with CBCT and medical CT imaging in dental applications to assess their relative safety and efficacy. Materials and Methods: We conducted a retrospective study using data from 100 patients who underwent both CBCT and medical CT scans for dental purposes. The radiation doses were measured in terms of dose-length product (DLP) for medical CT and dose-area product (DAP) for CBCT. The effective dose (ED) was calculated using appropriate conversion factors. Patient demographics, scan parameters, and radiation doses were recorded and analyzed. Results: The results indicated that the mean DLP for medical CT scans was 220 mGycm, whereas the mean DAP for CBCT scans was 150 mGycm². The corresponding mean effective doses for medical CT and CBCT were 2.5 mSv and 1.8 mSv, respectively. The radiation dose from CBCT was found to be approximately 28% lower than that from medical CT. Conclusion: This study demonstrates that CBCT imaging for dental applications results in significantly lower radiation doses compared to medical CT. While both modalities provide valuable diagnostic information, the choice of imaging technique should consider the balance between diagnostic quality and radiation exposure, especially for pediatric and high-risk patients. Dental practitioners should be aware of the potential dose reduction benefits associated with CBCT when appropriate for the clinical scenario.

Neutron dose evaluation inside high-energy accelerator irradiation vault using LR-115.

Recently, a new radiation therapy using a high-energy accelerator irradiation vault has attracted significant attention. This therapy is very effective in destroying cancer cells because it uses much higher energy than conventional radiation therapy. Nevertheless, it also has disadvantages due to its high energy and dose, resulting in the generation of secondary radiation such as X-rays and neutrons. In particular, neutrons have a higher radiation weighting factor than photons; therefore, they are more harmful to normal tissues. However, the popular neutron dosimeter CR-39 cannot evaluate high-dose neutrons. This paper proposes a novel method for measuring high-dose neutrons generated during cancer treatment. LR-115, which has low detection efficiency but is expected to be useful for evaluating high-dose neutrons, was used to evaluate the effective dose of neutrons in a high-energy accelerator irradiation room. The results were verified using MCNP 6.2, a Monte Carlo-based particle transport code. This study provides the lower limit for evaluating neutron effective dose using LR-115. The experimental results showed that the neutron effective dose increased linearly with beam current. These findings provide basic data for evaluating neutron effective dose for radiation protection.

Assessment of natural and artificial radioactivity concentrations in infant powdered milk consumed in Albania and estimation of the annual effective dose.

This study evaluates the radiological risk associated with the consumption of infant powdered milk in Albania. Infant powdered milk is the basic foodstuff for their growth and development in many countries around the world. The activity concentration of radionuclides (40K, 226Ra, 232Th and 137Cs) was measured in fourteen types by using the gamma-ray technique. The results indicated that the activity concentration of 40K, 226Ra and 232Th were detected in all selected samples, whereas 137Cs were not detected in most of them. The activity concentration of 40K, 226Ra and 232Th varies from 92.83 ± 4.32 to 400.53 ± 17.00 Bq kg-1, 0.80 ± 0.15 to 4.91 ± 0.28 Bq kg-1 and 0.19 ± 0.02 to 1.89 ± 0.14 Bq kg-1, respectively. The highest value for 137Cs was found to be 0.36 ± 0.03 Bq kg-1. The average values of Annual Effective Dose (AED) due to consumption of powdered milk were found to be 664.54 ± 31.11 µSv y-1 for infants ≤1 year and 138.53 ± 5.40 µSv y-1 for infants 1-2 years. The values of dose in this study were lower than the recommended limit of 1 mSv y-1 set by WHO/FAO and ICRP for all ages. Therefore, brands of powdered milk are safe, so, these can be normally consumed by infants in Albania.

Assessment of Occupational Radiation Exposures at Ghana Research Reactor-1 Facility.

The annual occupational doses for workers at the Ghana Research Reactor-1 facility were assessed for the period 2018-2021. The dose records of monitored staff were retrieved and analysis done for dose distribution and collective effective doses. Thermoluminiscent dosimeters were used to monitor the occupational exposures. The dosimeters were evaluated for the cumulative radiation dose levels using the Harshaw 6600 TLD reader system. Annual dose of 1.52 mSv/year was the maximum acquired by an individual. An annual average effective dose range of 0.20-1.36 mSv was determined for all workers. The annual total collective effective dose was established to be in the range of 0.40-10.08 man-Sv. The 20 mSv annual limit for occupational exposure was not exceeded for monitored workers. The assessment shows that the GHARR-1 facility, in terms of radiation health effects, is a favorable environment for workers since exposures are mostly below occupational exposure limit.

Radiation doses and diagnostic reference levels for common CT scans in adults in Northwest region of Iran.

This study aims to estimate organ dose and cancer risks, establish region-specific diagnostic reference levels (DRLs), and determine achievable doses (ADs) for common CT procedures in adults in the northwest of Iran. Effective and organ doses were estimated using VirtualDoseCT software in a sample of 480 adult patients who underwent head, sinus, chest, and abdomen-pelvis (AP) CT scans. The guidelines provided by the BEIR VII report were utilized to estimate cancer risks. Effective and organ doses for specific procedures were determined, with the highest mean organ dose being observed in the brain during head CT examinations, with a value of 54.02 mGy. It was observed that the lungs in chest examinations and the colon in AP examinations had the highest risk of cancer, with rates of 30.72 and 21.37 per 100,000 persons, respectively. Higher cancer risk values were generally exhibited by females compared to males. The DRLs for common CT examinations were established as follows: Head CT (CTDIvol 41 mGy, DLP 760 mGy cm), Sinus CT (CTDIvol 16 mGy, DLP 261 mGy cm), Chest CT (CTDIvol 8 mGy, DLP 287 mGy cm), and AP CT (CTDIvol 9 mGy, DLP 508 mGy cm). Significant variations in dose distribution among facilities were identified, indicating the need for optimization. The study highlights the importance of minimizing radiation exposure to critical organs and promoting patient safety in CT examinations. The establishment of region-specific DRLs and ADs can help optimize radiation doses and reduce cancer risks for patients.

Note on dose conversion for radon exposure.

The epidemiological approach to converting radon exposure to effective dose is examined. Based on the definition of the effective dose, the dose conversion is obtained from the equivalence of lung-specific detriment associated with low-LET radiation and with radon exposure. This approach most reliably estimates effective dose per radon exposure on the basis of epidemiological data and implicitly includes the radiation weighting factor required to calculate the effective dose from radon exposure using the dosimetric approach, applying biokinetic and dosimetric models. Consistency between the results of the epidemiological and dosimetric approaches is achieved by using a radiation weighting factor of about 10 for alpha particles instead of the current ICRP value of 20. In contrast, the epidemiological approach implemented in ICRP 65, and referred to as dose conversion convention, was based on direct comparison of total radiation detriment with lung detriment from radon exposure. With the revision of radiation detriments in ICRP 103, this approach can be judged to overestimate the effective dose per radon exposure by about a factor of two because the tissue weighting factor for lung differs from the value of relative detriment to which it relates.

A cross-sectional study on the correlation of image quality, effective dose, and body composition with thyroid, chest, and abdominal computed tomography scans.

Background: The rapid increase in the use of radiodiagnostic examinations in China, especially computed tomography (CT) scans, has led to these examinations being the largest artificial source of per capita effective dose (ED). This study conducted a retrospective analysis of the correlation between image quality, ED, and body composition in 540 cases that underwent thyroid, chest, or abdominal CT scans. The aim of this analysis was to evaluate the correlation between the parameters of CT scans and body composition in common positions of CT examination (thyroid, chest, and abdomen) and ultimately inform potential measures for reducing radiation exposure. Methods: This study included 540 patients admitted to Fudan University Shanghai Cancer Center from January 2015 to December 2019 who underwent both thyroid or chest or abdominal CT scan and body composition examination. Average CT values and standard deviation (SD) values were collected for the homogeneous areas of the thyroid, chest, or abdomen, and the average CT values and SD values of adjacent subcutaneous fat tissue were measured in the same region of interest (ROI). All data were measured three times, and the average was taken to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for each area. The dose-length product (DLP) was recorded, and the ED was calculated with the following: formula ED = k × DLP. Dual-energy X-ray was used to determine body composition and obtain indicators such as percentage of spinal and thigh muscle. Pearson correlation coefficient was used to analyze the correlations between body composition indicators, height, weight, body mass index (BMI), and ED. Results: The correlation coefficients between the SNR of abdominal CT scan and weight, BMI, and body surface area (BSA) were -0.470 (P=0.001), -0.485 (P=0.001), and -0.437 (P=0.002), representing a moderate correlation strength with statistically significant differences. The correlation coefficients between the ED of chest CT scans and weight, BMI, spinal fat percentage, and BSA were 0.488 (P=0.001), 0.473 (P=0.002), 0.422 (P=0.001), and 0.461 (P=0.003), respectively, indicating a moderate correlation strength with statistical differences. There was a weak statistically significant correlation between the SNR, CNR, and ED of the other scans with each physical and body composition index (P=0.023). Conclusions: There were varying degrees of correlation between CT image quality and ED and physical and body composition indices, which may inform novel solutions for reducing radiation exposure.

Assessment of radiation exposure risks in patients undergoing elastic stable intramedullary nailing: Insights from intraoperative fluoroscopy.

INTRODUCTION: Elastic stable intramedullary nailing (ESIN) is a well-defined and appropriate treatment of choice for long bone fractures. Despite its benefits, the risk of cancer from imaging devices is of particular concern for younger adults. So, this survey was conducted to estimate the doses administered to patients undergoing ESIN of long bone fractures utilizing a 2-dimensional (2D) C-arm fluoroscopy machine during surgery, as well as the carcinogenic risk associated with the use of the machine. METHODS: This study was conducted on 147 patients who required ESIN for long-bone fractures. Patients' demographic data, surgical data and imaging information were collected. For each patient, the organ doses and the effective doses were computed with the Monte Carlo PCXMC 2.0 simulation software. The cancer risk models proposed in the Biological Effects of Ionizing Radiation VII (BEIR VII) Phase 2 report were used to evaluate the risk of exposure-induced cancer death (REID) values. RESULTS: For all patients, the highest organ dose was delivered to the gonads. The mean effective dose was 0.026 ± 0.015 mSv and 1.3E-04 ± 1E-04 mSv for ESIN of femur and tibia fractures, respectively. Males had a mean REID of 1 per million, while females had a mean REID of 0.19 per million. The younger males had considerably higher REID values. The effective dose was significantly correlated with age, gender, and irradiation time. CONCLUSION: Low levels of effective doses and cancer risks associated with the utilization of the fluoroscopy machine in current practice were found in ESIN treatment of long-bone fractures. IMPLICATIONS FOR PRACTICE: This outcome will help to raise surgeons' awareness of radiation risks and encourage them to initiate measures to keep radiation dose and exposure time as low as reasonably achievable.

Evaluation of radioactivity concentration in farm fresh milk and concomitant dose to consumer.

In this study, activity concentrations of natural radionuclides in 28 raw milk samples collected from different dairy farms in Dhaka city of Bangladesh were measured using a high-purity germanium (HPGe) detector for the first time. The activity concentration of 226Ra, 232Th, and 40K in the investigated fresh milk samples ranged from BDL (Below detection level) to 26 ± 1.6 Bq/kg, BDL to 11.7 ± 3.3 Bq/kg and 101 ± 17 to 384 ± 32 Bq/kg, respectively. No artificial radionuclides were found in the investigated samples. Present results show inline within the range of available data in the literature. Annual committed effective doses were estimated following the consumption characteristics of raw milk by city population, values are found within the limiting range recommended by international organizations due to consumption of foodstuffs. Additionally, real-time gamma-ray dose rate in the farms/sampling locations was found in the range of 0.12 ± 0.01-0.20 ± 0.01 µSv/h by using a digital gamma survey meter (Gamma Scout) and the calculated maximum annual effective dose due to outdoor absorbed dose was found to be 0.25 mSv/y, which shows lower than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limit of 2.4 mSv/y. This study indicates that the concentration of radionuclides in the farm fresh milk of Dhaka city does not pose any unwanted risk to public health, and it is safe to consume by both children and adults with the current intake level.

Dose-response study of propofol combined with two different doses of esketamine for laryngeal mask airway insertion in women undergoing hysteroscopy.

Objective: To prospectively determine the median effective dose (ED50) of propofol for inhibiting a response to laryngeal mask airway (LMA) insertion when combined with different doses of esketamine in female patients. Methods: A total of 58 female patients (aged 20-60 years, ASAⅠ-Ⅱ) scheduled for elective hysteroscopy were enrolled and randomly divided into 2 groups, one of which was administered 0.2 mg/kg of esketamine (K1 group, n = 28) and the other 0.3 mg/kg of esketamine (K2 group, n = 30). The 2 groups received the corresponding doses of esketamine intravenously, followed by an intravenous injection of propofol (injection time was 30 s). The initial dose of propofol was 2 mg/kg, and the dose ratio of propofol in the adjacent patients was 0.9. If a positive reaction occurred due to LMA insertion, the dose ratio in the next patient was increased by 1 gradient; if not, the dose ratio was decreased by 1 gradient. The ED50, 95 % effective dose (ED95) and 95 % confidence interval (CI) of propofol for inhibiting a response to LMA insertion in the 2 esketamine groups were calculated using probit analysis. Results: The ED50 of propofol for inhibiting a response to LMA insertion in female patients was 1.95 mg/kg (95 % CI, 1.82-2.08 mg/kg) in the K1 group and 1.60 mg/kg (95 % CI, 1.18-1.83 mg/kg) in the K2 group. The ED95 of propofol for inhibiting a response to LMA insertion in female patients was 2.22 mg/kg (95 % CI, 2.09-2.86 mg/kg) in the K1 group and 2.15 mg/kg (95 % CI, 1.88-3.09 mg/kg) in the K2 group. Conclusion: Propofol combined with 0.3 mg/kg of esketamine has low ED50 and ED95 effective doses for inhibiting an LMA insertion response in female patients undergoing hysteroscopy and surgery. There were no significant adverse effects, but the additional dose of propofol and airway pressure were significantly higher than those in the group administered 0.2 mg/kg of esketamine. Based on the results, we recommend the combination of propofol with 0.2 mg/kg esketamine for optimal conditions during LMA insertion in women undergoing hysteroscopy.

Staff radiation doses during Sentinel Lymph Node procedure of breast cancer from injection to surgeon.

The Sentinel Lymph Node (SLN) or Sentinel Lymph Node Biopsy (SLNB) technique involves various professionals from different departments in clinical settings to manage breast cancer patients properly. Tracing the nodular involvement of breast cancer patients requires radiation source Tc99m labeled with colloidal albumin to be injected at the tumor site. The patient becomes a radiation source for a sufficient time, which concerns the Nuclear Medicine (NM) and surgical staff. The study aims to provide the radiation doses of staff in the NM department during the SLN scintigraphy procedure and obtain an empirical model for calculating the radiation doses to staff in the surgical department from that particular patient. Radiation doses in SLN technique for breast cancer patients are minimal, and a sufficient number of SLN biopsy procedures can be performed by hospital staff within the category of non-radiation workers.

The 90% effective dose (ED90) of remimazolam for inhibiting responses to the insertion of a duodenoscope during ERCP.

BACKGROUND: Compared to midazolam, remimazolam has a faster onset and offset of hypnotic effect, as well as cardiorespiratory stability, this study aims to determine the 90% effective dose (ED90) of remimazolam to inhibit responses to insertion of a duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP). METHODS: A dose-response study was carried out undergoing ERCP who received remimazolam-alfentanil anesthesia using 10 µg/kg of alfentanil between September 2021 and November 2021. The initial dose of remimazolam was 0.2 mg/kg. The dose was then decided based on the responses of earlier patients by exploiting the sequential ascend and descend according to a 9: 1 biased coin design. Upon failure, the dose of remimazolam was increased by 0.025 mg/kg in the next patient. When the insertion was successful, the succeeding patient was randomized to an identical dose or a dose that was lower by 0.025 mg/kg.The ED90 of remimazolam for inhibiting responses to the insertion of a duodenoscope during ERCP was calculated. Adverse events and complications of remimazolam were recorded. RESULTS: A total of 55 elderly patients (age > 65) were included in the study. 45 successfully anesthetized patients, and 10 unsuccessfully. The ED90 of remimazolam was 0.300 mg/kg (95% CI = 0.287-0.320). ED95 was 0.315 (95% CI = 0.312-0.323) and ED99 was 0.323 (95% CI = 0.323-0.325). Among the patients, 9 patients developed hypotension, 2 patients developed bradycardia and 1 patient developed tachycardia, and hypoxia occurred in 2 patients. CONCLUSIONS: A loading dose of 0.300 mg / kg of remimazolam for elderly patients undergoing ERCP can safely, effectively, and quickly induce patients to fall asleep and inhibit responses to the insertion of a duodenoscope. TRIAL REGISTRATION: The study protocol was registered at the website ClinicalTrials.gov on 22/09/2021(NCT05053763).

Characterization of natural radioactivity and relative dose due to consumption of edible bivalves inhabiting the Cochin Backwater Lagoon, Kerala, southwestern coast of India.

The study on natural radionuclides in edible bivalves from the Cochin backwater lagoon, Kerala, employing alpha spectrometry, revealed higher concentrations of 210Po and 210Pb compared to 238U and 232Th. The annual committed effective dose (ACED) for the adult coastal population was calculated at a range of 1494.9 to 5783.4 µSv y-1, with 210Po being the predominant contributor, responsible for about 85 % of the dose. This highlighted significant health risks, underscored by a calculated cumulative mortality and morbidity risk range between 5.23 × 10-3 and 2.02 × 10-2. These findings emphasized the need for further research and the development of regulatory measures to mitigate exposure risks.