Control effect of high aspherical lenticule in children and adolescents with low myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To explore the effect of high aspherical lenticule on controlling low myopia.METHODS: Prospective study. A total of 100 patients aged 7 to 12 years old with low myopia who visited our hospital from May 1 to 31, 2022 were collected. They were divided into two groups with 50 cases in each group according to the wishes of patients. The control group was given single vision glasses after optometry, while the study group was given high aspherical lenticule. The myopia progression(absolute value), axial length(AL)growth, transition rate to moderate myopia, and AL negative growth rate over 6 mo and 1 a were compared between the two groups.RESULTS: The myopia progression and the AL growth of study group was lower than that of the control group after 6 mo and 1 a(all P<0.001).The negative growth rate of AL after 6 mo of treatment was significantly higher than that of the control group(P<0.001). The transition rate to moderate myopia between the two groups was not statistically significant(P=0.62); while the transition rate to moderate myopia in the study group was significantly lower than that in the control group after wearing lens for 1 a(P<0.001), and there was no statistically significant difference in AL negative growth rate between the two groups(P=0.12). Compare with single vision glasses, high aspherical lenticule achieved an 88.2% control rate for low myopia progression over 6mo and a 90.0% control rate of AL growth. The control rate for low myopia to moderate myopia was 66.7%; while the control rate of myopia progression growth was 75.6% after wearing lens for 1a, the control rate of AL growth was 69.2%, and the control rate of the transition rate to moderate myopia was 88.9%.CONCLUSION: For children and adolescents aged 7 to 12 with low myopia, high aspherical lenticule was more effective than single vision glasses in controlling myopia, making it one of the optimal choices for myopia control.

An analysis of results of 392 times of CT quality control and room radiological protection testing in Guangdong Province, China / 中国辐射卫生

Objective To provide a theoretical basis for radiation health supervision through an analysis of the situation of computed tomography (CT) equipment quality control and CT room radiological protection in Guangdong Province, China in recent years. Methods We collected the data of 392 times of CT quality control and radiological protection testing by a third-party radiological health technical service institution in Guangdong Province from 2019 to 2021. We analyzed the levels of CT-owning hospitals, CT manufacturers, CT quality control test results, and the pass rate of radiation protection tests. Results The examined CT scanners were from different levels of hospitals in Guangdong Province, and were manufactured by nine major CT equipment manufacturers at home and abroad. The pass rate of CT room radiological protection was 99.88%, and the ambient dose equivalent rates of five monitoring points exceeded the limit, with four at the control room door and one at the shield wall of the room. The overall pass rate of CT equipment quality control was 99.49%, and the non-conforming parameters were the accuracy of positioning light and the deviation of reconstructed slice thickness. Conclusion In recent years, CT equipment quality control and room radiation protection in Guangdong Province have been at a high level.

Occupational radiation exposure in anesthesia for hepatic chemoembolization: a prospective study

Introduction Anesthetists play an important role during interventional radiology procedures. Like the main operator, anesthetists may also be subject to significant radiation levels in the fluoroscopy suite. Due to its complexity, hepatic chemoembolization procedures demand high fluoroscopic times and digital subtraction angiography images, exposing patients and medical staff to high radiation doses. Objective To assess and quantify the radiation to which one anesthetist was exposed over the course of seven consecutive hepatic chemoembolization procedures, and compare it to the exposure received by the main operator. Methods Medical staff dosimetry was evaluated during seven consecutive hepatic chemoembolization procedures conducted in a private hospital in Recife (Brazil), using thermoluminiscent dosimeters placed in regions of the head and torso. Results For the seven procedures evaluated in this study, the anesthetist received, on average, absorbed doses to the glabella, left eyebrow, right eyebrow and effective dose of 142.4 ± 72 µSv, 117.3 ± 66 µSv, 137.8 ± 71 µSv and 12.4 ± 8.4 µSv, respectively. Conclusions In some cases, ocular dose and effective dose received by the anesthetist may be 4 and 4.7 times greater, respectively, when compared to the main operator. According to the results of this study, the current occupational annual dose limit to the lens of the eye of 20 mSv can be exceeded with only two hepatic chemoembolization procedures per week if adequate radiation protection conditions are not guaranteed.

Introducción El anestesiólogo desempeña un papel importante durante los procedimientos de radiología intervencionista. Al igual que el operador principal, el anestesiólogo también puede estar expuesto a niveles significativos de radiación en la sala de fluoroscopía. Debido a su complejidad, durante los procedimientos de quimioembolización hepática se deben utilizar imágenes de fluoroscopía y angiografía de sustracción digital por períodos prolongados, exponiendo a los pacientes y al personal médico a dosis elevadas de radiación. Objetivo Evaluar y cuantificar la radiación a la cual se expuso un anestesiólogo durante el transcurso de siete procedimientos consecutivos de quimioembolización hepática, y comparar con la exposición recibida por el operador principal. Métodos Evaluación de la dosimetría ocupacional durante siete procedimientos consecutivos de quimioembolización hepática realizados en un hospital privado de Recife (Brasil) por medio de dosímetros termoluminiscentes ubicados en regiones de la cabeza y el torso. Resultados Para los siete procedimientos evaluados en este estudio, el anestesiólogo recibió, en promedio, dosis absorbidas en el entrecejo, la ceja izquierda, la ceja derecha y dosis efectivas de 142,4 ± 72 µSv, 117,3 ± 66 µSv, 137,8 ± 71 µSv y 12,4 ± 8,4 µSv, respectivamente. Conclusiones En algunos casos, la dosis ocular y la dosis efectiva que recibe el anestesiólogo puede ser, respectivamente, entre 4 y 4,7 veces más alta que la que recibe el operador principal. De acuerdo con los resultados de este estudio, el límite ocupacional anual de dosis en cristalino (20 mSv) se puede superar con apenas dos procedimientos de quimioembolización hepática a la semana en caso de no garantizarse las condiciones adecuadas de protección contra la radiación.

Non-pathologic components are associated with reduced visual acuity in myopes after spectacle correction

Purpose: To find the association between reduced best?corrected visual acuity and non?pathologic components after optical correction in individuals with low to high myopia. Methods: Myopic children under 16 years of age were reviewed using electronic medical records and the following data were extracted and recorded: participant’s age, gender, uncorrected visual acuity (UCVA), manifest refraction, and best corrected visual acuity (BCVA). Spherical equivalent and cylinder were classified into low, moderate, and high categories based on the magnitude range. Similarly, astigmatism was defined into with?the?rule, against?the?rule, and oblique based on the location of the steepest meridian. Reduced BCVA was defined when the decimal visual acuity was less than 0.66 (equivalent to Snellen’s acuity of 6/9 or 20/30). Logistic regression was performed to test the factors associated with reduced visual acuity after optical correction in the absence of myopic pathologic changes. Statistical significance was considered if P < 0.05. Results: Overall 44.9% (N = 242/538) of myopes had reduced best?corrected visual acuity (BCVA) and none of the patients had pathologic myopic lesions. Using logistic regression, we found that high spherical refraction (OR 27.98, 95% CI 14.43–54.25, P < 0.001) and moderate spherical refraction (OR 5.52, 95% CI 2.56–11.91, P < 0.001) were significantly associated with reduced best corrected visual acuity despite any pathological lesions. Additionally, oblique and ATR astigmatism were associated with reduced visual acuity in myopic children with (OR 2.05, 95% CI 0.77–5.42) and (OR 1.59, 95% CI 0.82–3.08). Conclusion: Higher magnitude of refractive error components causes reduced visual acuity in the absence of pathologic changes.

Prediction of spherical equivalent refraction and axial length in children based on machine learning

Purpose: Recently, the proportion of patients with high myopia has shown a continuous growing trend, more toward the younger age groups. This study aimed to predict the changes in spherical equivalent refraction (SER) and axial length (AL) in children using machine learning methods. Methods: This study is a retrospective study. The cooperative ophthalmology hospital of this study collected data on 179 sets of childhood myopia examinations. The data collected included AL and SER from grades 1 to 6. This study used the six machine learning models to predict AL and SER based on the data. Six evaluation indicators were used to evaluate the prediction results of the models. Results: For predicting SER in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the multilayer perceptron (MLP) algorithm, MLP algorithm, orthogonal matching pursuit (OMP) algorithm, OMP algorithm, and OMP algorithm, respectively. The R2 of the five models were 0.8997, 0.7839, 0.7177, 0.5118, and 0.1758, respectively. For predicting AL in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the Extra Tree (ET) algorithm, MLP algorithm, kernel ridge (KR) algorithm, KR algorithm, and MLP algorithm, respectively. The R2 of the five models were 0.7546, 0.5456, 0.8755, 0.9072, and 0.8534, respectively. Conclusion: Therefore, in predicting SER, the OMP model performed better than the other models in most experiments. In predicting AL, the KR and MLP models were better than the other models in most experiments.

Effectiveness of 0.01% atropine in anisomyopic children

Purpose: To investigate the change in ocular parameters of anisomyopic children treated with 0.01% atropine. Methods: This retrospective study analyzed the data of anisomyopic children who underwent comprehensive examination at a tertiary eye center in India. Anisomyopic subjects (difference of ?1.00 D) of age 6–12 years who were treated with 0.01% atropine or prescribed regular single vision spectacle and had follow?ups of more than 1 year were included. Results: Data from 52 subjects were included. No difference was observed in the mean rate of change of spherical equivalent (SE) of more myopic eyes between 0.01% atropine (?0.56 D; 95% confidence interval [CI]: ?0.82, ?0.30) and single vision lens wearers (?0.59 D; 95% CI: ?0.80, ?0.37; P = 0.88). Similarly, insignificant change in the mean SE of less myopic eyes was noted between the groups (0.01% atropine group, ?0.62 D; 95% CI: ?0.88, ?0.36 vs. single vision spectacle wearer group, ?0.76 D; 95% CI: ?1.00, ?0.52; P = 0.43). None of the ocular biometric parameters showed any difference between the two groups. Though anisomyopic cohort treated with 0.01% atropine revealed a significant correlation between the rate of change of mean SE and axial length in both eyes (more myopic eyes, r = ?0.58; P = 0.001 and less myopic eyes, r = ?0.82; P < 0.001) compared to single vision spectacle wearer group, the change was not significant. Conclusion: Administration of 0.01% atropine had minimal effect on reducing the rate of myopia progression in anisomyopic eyes.

Impacto de la COVID-19 en la progresión de la miopía en niños / Impact of COVID-19 on myopia progression in children

Introducción: La Organización Mundial de la Salud considera a la miopía un problema de salud mundial debido a su prevalencia creciente. Se espera que afecte al 52 % de la población mundial en 2050. Objetivo: Determinar la progresión de la miopía durante la pandemia de COVID-19 con respecto al período previo al confinamiento. Métodos: Se realizó un estudio descriptivo y ambispectivo de una serie de 12 pacientes atendidos en la Consulta de Oftalmología Pediátrica del Instituto Cubano de Oftalmología "Ramón Pando Ferrer" antes de la pandemia y que acudieron en el período de confinamiento por la COVID-19 para su seguimiento. Las variables evaluadas fueron edad, género, antecedentes patológicos familiares de miopía, horas pantalla, equivalente esférico y biometría. Resultados: El promedio de edad fue de 9,7 años y el 58,3 por ciento correspondió al sexo femenino. El 75 por ciento de los pacientes tenían antecedentes patológicos familiares de miopía y el tiempo estimado frente a pantalla fue de 5,3 ± 0,8 h diarias. La media de la biometría se incrementó en el tiempo de 23 mm en 2019 a 25,5 mm en 2021. La diferencia de la media del equivalente esférico previo a la COVID-19 fue -0,89 y -0,84 para ojo derecho y el ojo izquierdo, respectivamente. En la etapa epidémica se percibió un aumento hasta -1,97 y -1,72. Conclusiones: El incremento del uso de los medios digitales debido al confinamiento ha causado la progresión de la miopía(AU)

Introduction: Myopia is considered a global health problem by the World Health Organization due to its increasing prevalence and is expected to affect 52 percent of the world's population by 2050. Objective: To determine the progression of myopia during the COVID-19 pandemic with respect to the pre-confinement period. Methods: A descriptive and ambispective study of a series of 12 patients treated at the Pediatric Ophthalmology Clinic of the Cuban Institute of Ophthalmology "Ramón Pando Ferrer" before the pandemic and who visited the hospital during the COVID-19 confinement period for follow-up, was carried out. The variables evaluated were age, gender, family history of myopia, screen hours, spherical equivalent and biometry. Results: The average age was 9.7 years and 58.3 percent of the patients were females. Seventy-five percent of the patients had a family history of myopia and the estimated time in front of the screen was 5.3 ± 0.8 h per day. The medium biometry increased over time from 23 mm in 2019 to 25.5 mm in 2021. The difference in medium pre-COVID-19 spherical equivalent was -0.89 and -0.84 for right eye and left eye, respectively. In the epidemic stage, an increase to -1.97 and -1.72 was perceived. Conclusions: Increased use of digital media due to confinement has caused myopia progression(AU)

Prevalence and risk factors of tessellated fundus in Tianjin Medical University students / 中华眼底病杂志

Objective:To investigate the prevalence and risk factors of tessellation fundus (TF) among Tianjin Medical University students with different refractive statuses.Methods:A cross-sectional study. From September to December 2019, 346 students from Tianjin Medical University were randomly selected and underwent slit-lamp examination, non-cycloplegic auto-refraction, subjective refraction, best-corrected visual acuity, ocular biometric measurement, and non-dilation fundus photography. The differences in the prevalence of TF in basic characteristics and ocular biometric parameters were compared. Based on the equivalent spherical (SE), refractive status was divided into the non-myopia group (SE>-0.50 D) and the myopia group (SE≤-0.50 D). The myopia group was further divided into mild myopia group (-3.00 D<SE≤-0.50 D), moderate myopia group (-6.00 D<SE≤-3.00 D), and high myopia group (SE≤-6.00 D). According to the axis length (AL), the subjects were divided into AL<24 mm group, 24-26 mm group, and >26 mm group. The logistic regression was used to analyze the risk factors affecting TF. Trend tests were performed for each risk factor and TF.Results:Of the 346 subjects, 324 (93.6%, 324/346) were myopia, of whom 73 (21.1%, 73/346), 167 (48.3%, 167/346), and 84 (24.3%, 84/346) were mild myopia, moderate myopia, and high myopia, respectively; 22 (6.4%, 22/346) were non-myopia. There were 294 (85.0%, 294/346) students with TF in the macula, including 9 (40.91%, 9/22), 58 (79.45%, 58/73), 145 (86.83%, 145/167), and 82 (97.62%, 82/84) in non-myopia, low myopia, moderate myopia, and high myopia group, respectively; 52 (15.0%, 52/346) students were without TF in the macula. There were statistically significant gender differences ( χ2=4.47), SE ( t=6.29), AL ( t=-8.29), anterior chamber depth ( Z=-2.62), lens thickness ( Z=-2.23), and average corneal radius ( Z=-3.58) between students with and without TF in the macula ( P<0.05). Spherical equivalent and axial length were independent risk factors for TF and its severity ( P≤0.001). With an increasing degree of myopia, and increasing axial length, the risk of TF increased ( P for trend<0.001). Conclusions:The prevalence of TF is 85.0% among Tianjin Medical University students. TF is detected in the fundus of no myopia, mild myopia, moderate myopia and high myopia. The degree of myopia is higher, the AL is longer, the possibility of TF is higher.

Dose volume histogram prediction method for organ at risk in VMAT planning of nasopharyngeal carcinoma based on equivalent uniform dose / 中华放射肿瘤学杂志

Objective:To evaluate the practicability of dose volume histogram (DVH) prediction model for organ at risk (OAR) of radiotherapy plan by minimizing the cost function based on equivalent uniform dose (EUD).Methods:A total of 66 nasopharyngeal carcinoma (NPC) patients received volume rotational intensity modulated arc therapy (VMAT) at Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences from 2020 to 2021 were retrospectively selected for this study. Among them, 50 patients were used to train the recurrent neutral network (RNN) model and the remaining 16 cases were used to test the model. DVH prediction model was constructed based on RNN. A three-dimensional equal-weighted 9-field conformal plan was designed for each patient. For each OAR, the DVHs of individual fields were acquired as the model input, and the DVH of VMAT plan was regarded as the expected output. The prediction error obtained by minimizing EUD-based cost function was employed to train the model. The prediction accuracy was characterized by the mean and standard deviation between predicted and true values. The plan was re-optimized for the test cases based on the DVH prediction results, and the consistency and variability of the EUD and DVH parameters of interest (e.g., maximum dose for serial organs such as the spinal cord) were compared between the re-optimized plan and the original plan of OAR by the Wilcoxon paired test and box line plots.Results:The neural network obtained by training the cost function based on EUD was able to obtain better DVH prediction results. The new plan guided by the predicted DVH was in good agreement with the original plan: in most cases, the D 98% in the planning target volume (PTV) was greater than 95% of the prescribed dose for both plans, and there was no significant difference in the maximum dose and EUD in the brainstem, spinal cord and lens (all P>0.05). Compared with the original plan, the average reduction of optic chiasm, optic nerves and eyes in the new plans reached more than 1.56 Gy for the maximum doses and more than 1.22 Gy for EUD, and the average increment of temporal lobes reached 0.60 Gy for the maximum dose and 0.30 Gy for EUD. Conclusion:The EUD-based loss function improves the accuracy of DVH prediction, ensuring appropriate dose targets for treatment plan optimization and better consistency in the plan quality.

Research progress on use of tissue equivalent filler in postmastectomy radiation therapy of breast cancer / 中华放射肿瘤学杂志

Although the use of postmastectomy radiation therapy (PMRT) has been proven to bring survival benefit to breast cancer patients, the use of chest wall tissue equivalent filler (bolus) remains controversial. In recent years, a large number of studies have shown that the use of bolus in PMRT does not significantly improve the local control rate, while it can significantly increase the acute skin toxicity, and even leads to more frequent and longer treatment interruption. Existing retrospective studies have indicated that for breast cancer patients undergoing mastectomy and systemic therapy, if there is no skin invasion, it is recommended not to routinely use bolus during radiotherapy. However, higher-level clinical studies are needed for further confirmation.

Dosimetric analysis of the optimization algorithm for intracavitary/interstitial brachytherapy of cervical cancer / 中华放射医学与防护杂志

Objective:To provide a basis for selecting the optimization method for intracavitary/interstitial brachytherapy (IC/ISBT) of cervical cancer by comparing graphical optimization (GO), inverse planning simulated annealing (IPSA), and hybrid inverse planning optimization (HIPO) using dosimetric and radiobiological models.Methods:This study selected 65 patients with cervical cancer who were treated with image-guided IC/ISBT. The afterloading therapy plans for these patients were optimized using GO, IPSA, and HIPO individually, with a prescription dose high-risk clinical target volume (HRCTV) D90 of 6 Gy. The non-parametric Friedman test and the non-parametric Wilcoxon rank test were employed to analyze the differences in duration, dose-volume parameters, and radiobiology between the three types of optimized plans. Results:Inverse planning optimization (IPSA: 46.53 s; HIPO: 98.36 s) took less time than GO (135.03 s). In terms of gross target volume (GTV) dose, the high-dose irradiation V150% (53.66%) was slightly higher in the HIPO-optimized plans, while the V200% (30.29%) was higher in the GO-optimized plans. The GO-optimized plans had a higher conformity index (CI; 0.91) than other plans, showing statistically significant differences. Compared with other plans, the HIPO-optimized plans showed the lowest doses of D1 cm 3 and D2 cm 3 at bladders and rectums and non-statistically significant doses at small intestines ( P > 0.05). In terms of the equivalent uniform biologically effective dose (EUBED) for HRCTV, the HIPO-optimized plans showed a higher value (12.35 Gy) than the GO-optimized plans (12.23 Gy) and the IPSA-optimized plans (12.13 Gy). Moreover, the EUBED at bladders was the lowest (2.38 Gy) in the GO-optimized plans, the EUBED at rectums was the lowest (3.74 Gy) in the HIPO-optimized plans, and the EUBED at small intestines was non-significantly different among the three types of optimized plans ( P = 0.055). There was no significant difference in the tumor control probability (TCP) predicted using the three types of optimized plans ( P > 0.05). The normal tissue complication probabilities (NTCPs) of bladders and rectums predicted using the HIPO-optimized plans were lower than those predicted using the GO- and IPSA-optimized plans( χ2 = 12.95-38.43, P < 0.01), and the NTCP of small intestines did not show significant differences ( P > 0.05). Conclusions:Among the three types of optimization algorithms, inverse optimization takes less time than GO. GO-optimized plans are more conformal than IPSA- and HIPO-optimized plans. HIPO-optimized plans can increase the biological coverage dose of the target volume and reduce the maximum physical/biological exposure and NTCP at bladders and rectums. Therefore, HIPO is recommended preferentially as an optimization algorithm for IC/ISBT for cervical cancer.

Study on the effect of personal radiological protective equipment used in diagnostic radiology / 中华放射医学与防护杂志

Objective:To study the actual effect of the use of personal protective equipment of the examined individuals, and provide reference and basis for the correct use of personal protective equipment and the radiological health administrative law enforcement.Methods:From February to June 2022, the imaging department of Qingdao Municipal Hospital selected 170 patients who underwent X-ray imaging examination (oral panoramic, dental radiography, DR photography, CT scanning), including 25 with oral panoramic and dental radiography, 60 with CT scanning and 60 with DR imaging. The thermoluminescent dosimeter was used to detect the ambient dose equivalent at the point of concern for 170 examined individuals who have used personal protective equipment to cover their sensitive parts, and to analyze the data detected at the same point as above when routinely using the same equipment.Results:There was a statistically significant difference in the dose equivalent at the same points inside and outside the lead neckband ( t=-2.23, P<0.05). There was no statistically significant difference in the dose equivalent at the same point inside and outside the lead collar during dental radiography ( P>0.05). During DR photography (chest PA, lateral and lumbar AP), the examined individuals were wearing lead aprons. Among them, there was a statistically significant difference in the dose equivalent at the same points inside and outside the lead aprons of children′s chest PA and adults′ chest PA ( U=10.00, 19.00, P<0.05). There was no statistically significant difference in the dose equivalent at the same points inside and outside the lead aprons of adult′s chest PA and lumbar AP ( P>0.05). When performing CT scan (chest or upper abdomen), there was a statistically significant difference in the dose equivalent at the same points of wrapped lead aprons( U=878.50, 11.00, P<0.05). Conclusions:The correct use of personal protective equipment is a complex technical problem. It is very important to fully and accurately understand the optimization principle of radiation protection and correctly use personal protective equipment for the examined individuals. The administrative punishment of radiation health on the use of personal protective equipment of the examined individuals should be cautious.

Investigation on present state of radiation protection of a 60Co irradiation facility / 中华放射医学与防护杂志

Objective:To explore the present state of radiation protection in an operational large-sized irradiation facility and the distribution of incurred radiation doses in the controlled area under abnormal conditions, and to analyze the acompanied radiation risk.Methods:With an irradiation facility in operation as the research object, the radiation doses were measured using AT1121 X and gamma dose rate meters for the soruce both in working and storage. Thermoluminescent dosimeters (TLDs) were used to measure the dose distribution in an irradiation field under abnormal conditions. The radiation safety features were checked against the several relevant national standards, with the radiation risks evaluated.Results:The radiation dose rates were in the range of 0.09-0.11 μSv/h, lower than the environmental background level whether in storage or working. Under abnormal working conditions, the radiation dose values from high to low were 1.0-101.3 Sv, 32.7-514.0 mSv and 8.7-183.2 μSv in the irradiation field, respectively. At the outside maze, the doses were close to the background level.Conclusions:The protection features of the irradiation facility meet the requirements of the relevant national standards. Under abnormal conditions, radiation could cause serious damages to the persons staying in the irradiation field. These persons were suggested to access to maze as soon as possible to reduce the exposure time, and activate the emergency protection equipments to deescalate the 60Co source onto the well.

Development of a portable radiation detector for nuclide identification based on CdZnTe / 中国辐射卫生

Objective To develop a portable nuclear radiation detector with low-energy γ-nuclide recognition capability for rapid measurement of the dose levels in low-energy radiation fields and identification of nuclides. Methods A digital multi-channel circuit was developed for a detector based on the room temperature semiconductor cadmium zinc telluride, nuclide recognition was achieved using an intelligent nuclide recognition algorithm, and the energy response function G(E) was used to calculate the real-time ambient dose equivalent rate H*(10). Results The portable spectrometer had a minimum detectable energy of 20 keV, and the typical energy resolution for low-energy X-rays was > 4.10% at 59.5 keV and 20℃, enabling accurate identification of 241Am nuclide. Conclusion The device has a good measurement performance for low-energy γ/X rays, effectively addressing the limitations of existing devices for monitoring low-energy radiation fields, and provide reliable technical methods for monitoring and emergency response in spent fuel reprocessing plants or nuclear material production plants.

Study on the difference of high frequency dielectric properties of biological tissues measured by air and packed coaxial probe / 生物医学工程学杂志

In this paper, the differences between air probe and filled probe for measuring high-frequency dielectric properties of biological tissues are investigated based on the equivalent circuit model to provide a reference for the methodology of high-frequency measurement of biological tissue dielectric properties. Two types of probes were used to measure different concentrations of NaCl solution in the frequency band of 100 MHz-2 GHz. The results showed that the accuracy and reliability of the calculated results of the air probe were lower than that of the filled probe, especially the dielectric coefficient of the measured material, and the higher the concentration of NaCl solution, the higher the error. By laminating the probe terminal, liquid intrusion could be prevented, to a certain extent, to improve the accuracy of measurement. However, as the frequency decreased, the influence of the film on the measurement increased and the measurement accuracy decreased. The results of the study show that the air probe, despite its simple dimensional design and easy calibration, differs from the conventional equivalent circuit model in actual measurements, and the model needs to be re-corrected for actual use. The filled probe matches the equivalent circuit model better, and therefore has better measurement accuracy and reliability.

Value of generalized equivalent uniform dose optimization in radiotherapy for chest malignant tumors / 中国辐射卫生

Objective To explore the value of generalized equivalent uniform dose (gEUD) optimization in radiotherapy for chest malignant tumors. Methods Sixty patients with chest malignant tumors who were treated in Center for Tumor Radiotherapy, Chizhou Municipal People’s Hospital, Anhui Province, China from October 2021 to June 2022 were enrolled; each patient underwent tumor localization with a conventional fixed computed tomography scan. The patients were divided into two groups using the same field direction and weight in the Varian Eclipse 15.6 planning system. The first group was planned using the conventional physical dose-volume objective function plus the Upper gEUD objective function, with organs at risks (OARs) optimized with the EUD values suggested by the Varian Eclipse 15.6 planning system. The second group only adopted the conventional physical dose-volume objective function for OARs optimization. The two groups were compared for the radiation doses delivered to the OARs. Results Compared with the conventional physical dose-volume objective function alone, the addition of Upper gEUD objective function resulted in no significant difference in lung V5Gy, but resulted in significant reductions in V20Gy and mean dose in the lungs; some reductions in V30Gy, V40Gy, and mean dose in the heart; and significant reductions in the maximum dose in the spinal cord. Conclusion The gEUD objective optimization can effectively protect the normal tissue in the radiotherapy for chest malignant tumors and thus is recommended in radiotherapy planning.

Analysis of refractive parameters and theirs correlation with spherical equivalent in preschool children aged 3 to 6 years / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the distribution of refractive parameters and theirs correlation with spherical equivalent(SE)in preschool children aged 3 to 6 years, and evaluate the accuracy of each screening index in diagnosing refractive errors.METHODS: Cross-sectional study. A total of 791 preschool children, ranging from 3 to 6 years old, who consented to undergo mydriatic refraction were selected. Axial length(AL), corneal refractive power(K), and SE were measured after microcoria optometry and mydriatic optometry. Additionally, the corneal radius of curvature(CR)and the axial length/corneal radius of curvature(AL/CR)ratio were calculated.RESULTS: A total of 791 students participated in the study, out of which 400(50.6%)were male and 391(49.4%)were female. The mean values for AL, CR, AL/CR, and SE were 22.62±0.94mm, 7.81±0.29mm, 2.90±0.09, and +1.95±1.31D, respectively. AL, CR, and AL/CR increased with age. AL and CR were significantly higher in males than in females(all P&#x003C;0.001), while there was no statistically significant difference between AL/CR and SE in males and females(P=0.82, 0.19). The correlation coefficients of SE and AL/CR, AL and CR were -0.86, -0.50 and 0.16, respectively. The results of multiple linear regression analysis indicate that for each unit increase in AL/CR, there was a corresponding shift of 10.91 towards myopia in SE. The sensitivity of AL/CR in screening for myopia was 94.44%, with a specificity of 90.46% and a Youden index of 0.84. For screening myopia under microcoria optometry, the sensitivity was 100%, with a specificity of 66.09% and a Youden index of 0.66. The area under the curve was 0.967 and 0.809 when the ROC curves were plotted using AL/CR and AL as indicators for screening myopia, respectively.CONCLUSION: For large group screening activities where mydriatic optometry is not feasible, AL/CR is better for evaluating refractive status and identifying children with myopia and hyperopia reserve that are lower than normal for their age, compared to AL and microcoria optometry.

Effectiveness of personal dose monitoring intercomparison results in a laboratory in Shanghai / 环境与职业医学

Background Individual monitoring of occupational external exposure is an essential part of the occupational health management of radiation workers, and is an important basis for the evaluation of individual absorbed dose and the diagnosis of occupational radiation diseases. Continuous participation of monitoring service providers in intercomparison is a fundamental quality assurance for routine monitoring, which can identify problems and improve them in time. Objective Taking the Laboratory of Radiation Protection in Shanghai Institute of Preventive Medicine as an example, to evaluate the performance of an individual occupational external dose monitoring system in the laboratory, identify influencing factors of the monitoring results, and provide a basis for improving the quality of daily monitoring by analyzing the process and results of a national intercomparison of individual dose monitoring. Methods According to the Testing criteria of personnel dosimetry performance for external exposure (GBZ 207-2016), and the relevant requirements of Class II (photon) inspection, a total of 20 groups of blind sample dosimeters were measured for four consecutive years from 2018 to 2021. The radiation energy source of each group was identified, and related personal dose equivalent Hp(10), the uncertainty of measurement results, and the deviation between the reported value and the reference value were calculated. The national intercomparison process and results of individual dose monitoring were also analyzed. Results The energy sources of the blind samples in the tested laboratory for four years were N100 or Cs-137. The reported dose values of the blind samples were 0.57-4.61 mSv, the combined uncertainties were 0.043-0.365 mSv, the expanded uncertainties (k=2) were 0.09-0.73 mSv, and the relative expanded uncertainties (k=2) were 13.8%-16.4%. The single-group performance ∣Pi∣ of 20 sets of blind samples in the four years was ≤0.10, the yearly comprehensive performance of 5 sets of blind samples was ≤0.10, and the yearly Q score of the test report was >15 points. The laboratory achieved excellent results in the national intercomparison of individual dose monitoring in four consecutive years, except the Q value not reaching full score. Conclusion The laboratory exhibits standardized data processing of individual dose monitoring, generates accurate and reliable results, and meets the requirements of relevant national standards; but it should continue to participate in the national intercomparison of individual dose monitoring, strengthen the angular response research of energy identified dosimeter, improve the monitoring ability of low-dose X-rays, analyze the key points of reducing the uncertainty of measurement results, and continuously improve the monitoring ability.

Effects of low-energy red light on choroidal thickness and spherical equivalent and axial length in myopic children / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To systematically evaluate the effects of low-energy red light on choroidal thickness(ChT), spherical equivalent(SE), and axial length(AL)in myopic children.METHODS: A total of 8 databases, including Pubmed, Embase, Cochrane Library, Web of Science, CNKI, WanFang Database, VIP Database and China Biomedical Literature Database, were electronically retrieved to collect the clinical randomized controlled trial(RCT)of low-energy red light in myopia, with red light intervention as an experimental group and glasses as a control group. The retrieval time limit is from the establishment of the database to January 2023. According to the recommendation of the Cochrane Handbook, literature quality and risk of bias were evaluated. Revman5.4 software was used for Meta-analysis.RESULTS: Totally 8 RCT about red-light treatment with myopia were included. The sample size for ChT analysis contained 407 eyes in the red-light group and 425 eyes in the control group; SE analysis included 490 eyes in the red-light group and 518 eyes in the control group; sample size for AL analysis were 518 eyes in the red-light group and 539 eyes in the control group. The differences in ChT, SE and AL between the groups were statistically significant(ChT: WMD=37.81, 95%CI: 21.55～54.07, P&#x003C;0.001; SE: WMD=0.58, 95%CI: 0.46～0.71, P&#x003C;0.001; AL: WMD=-0.31, 95%CI: -0.39～-0.24, P&#x003C;0.001).CONCLUSION: Specific red light can promote the increase of ChT while inhibit SE and AL. However, its long-term efficacy and side effects remain unclear. The above conclusions need to be further clarified by more RCT with large samples.

Comparison of two analysis methods of opioid consumption sum in medical institutions / 中国药房

OBJECTIVE To compare the similarities and differences of the two methods in analyzing the use of opioids in third grade class A medical institutions and provide a reference for the management of opioids in medical institutions. METHODS Two methods， Defined Daily Dose （DDD） and Oral Morphine Equivalent （OME）， were used to count the opioid prescription data of five comprehensive medical institutions of third grade class A （named H1-H5） in Shanxi province in 2020， calculate consumption sum of opioid， annual per capita consumption sum， patient cost burden and drug consumption sum ratio， compare the index results presented by the two analysis methods， and explore the application scenarios of the advantages of each of the two evaluation methods. RESULTS The ranking of consumption sum of opioid and patient cost burden calculated by the two methods was the same in the five sample medical institutions， but the ranking of per capita consumption sum was different. Taking the 5 medical institutions as a whole， the top 4 rankings of consumption sum ratio for each species of opioid compared by both methods were the same， i. e. remifentanil＞sufentanil＞oxycodone＞morphine. The ratio of remifentanil was close to 50%. When comparing the ranking of consumption sum ratio in each medical institution， the ranking calculated by the two methods was different for those medical institutions except for H1 medical institutions. The consumption sum ratio of fentanyl calculated by DDD method was significantly higher than that of OME method； whereas consumption sum ratio of remifentanil calculated by OME method was significantly higher than that of DDD method. Perioperative patients had the highest consumption sum ratio， about 50%. The consumption sum ratio of critically ill patients in H3 jwsydey@163.com medical institutions and inpatient patients with cancer pain and other patients in H5 medical institutions calculated by DDD method was significantly higher than that by OME method. There were differences in the order of cost burden of different types of patients calculated by two methods. CONCLUSIONS DDD method can accurately reflect the dosage of opioid drugs and facilitate the monitoring and management of the dosage； OME method can more reflect the analgesic effect and compare the cost burden of patients.