Niveles de referencia diagnósticos en equipos de radiografía dental en Bogotá, Colombia

Introducción: Las radiografías dentales son una de las exposiciones médicas más frecuentes a la radiación ionizante. El uso de radiación ionizante está asociado a un riesgo probable de desencadenar efectos biológicos adversos y posibles daños a la salud del paciente. Para evitar que los pacientes reciban dosis innecesariamente altas durante estas exposiciones, la Comisión Internacional de Protección Radiológica recomienda la utilización de los niveles de referencia para diagnóstico, como una herramienta efectiva de ayuda a la optimización de la protección radiológica de los pacientes. Objetivo: Estimar los niveles de referencia para diagnóstico en radiografía dental intraoral y panorámica en la ciudad de Bogotá, D. C. Metodología: Se evaluaron los parámetros de exposición radiográficos de los equipos y la calidad de imagen en 68 equipos de radiografía dental periapical y 23 equipos de radiografía panorámica. Se estimaron las magnitudes dosimétricas de kerma incidente en aire (Kai) en equipos intraorales para la radiografía de un maxilar molar de un adulto y el producto kerma aire-área (PKA) en equipos de radiografía panorámica en un examen de un adulto estándar. Resultados: El tercer cuartil de la distribución de kerma incidente en aire para radiografía intraoral fue de 3,3 mGy y del producto kerma aire-área para radiografía panorámica fue de 103,9 mGycm2. En la distribución de frecuencias de kerma incidente en aire para radiografía intraoral, el porcentaje más alto de equipos estuvo en el rango de 2,0-3,0 mGy. En la distribución de frecuencias del producto kerma aire-área para los equipos de radiografía panorámica, el porcentaje más alto de equipos estuvo en el rango de 60 a 80 mGycm2. Discusión: Las instituciones consideradas para establecer los Niveles de Referencia para Diagnóstico en este estudio contaron con una adecuada calidad de la imagen evaluada con un maniquí dental, pero las variaciones en las dosis de radiación entre instituciones señalan la necesidad de implementar herramientas que contribuyan a la optimización de las prácticas. Conclusiones: Se recomienda usar los valores de los niveles de referencia para diagnóstico encontrados en esta investigación para optimizar la protección radiológica en las exposiciones radiológicas dentales, y se espera que este estudio sirva de base para nuevas investigaciones en las demás ciudades del país.

Introduction: Dental X-rays are one of the most frequent medical exposures to ionizing radiation. The use of ionizing radiation is associated with a probable risk of triggering adverse biological effects and possible damage to the patient's health. To prevent patients from receiving unnecessarily high doses during these exposures, the International Commission on Radiological Protection recommends the use of diagnostic reference levels as an effective tool to help optimize radiological protection for patients. Objective: To estimate diagnostic reference levels in intraoral and panoramic dental radiography in the city of Bogotá, D.C. Methodology: In 68 periapical dental radiography equipment and 23 panoramic radiography equipment, the radiographic exposure parameters of the equipment and image quality were evaluated. The dosimetric magnitudes of incident air kerma (Ka,i) in intraoral equipment for the radiography of a maxillary molar of an adult and the air kerma-area product (PKA) in panoramic radiography equipment in a standard adult examination were estimated. Results: The third quartile of the incident air kerma distribution for intraoral radiography was 3,3 mGy and the air kerma-area product for panoramic radiography was 103,9 mGycm2. In the frequency distribution of incident air kerma for intraoral radiography, the highest percentage of equipment was in the range of 2,0-3,0 mGy, and in the frequency distribution of the air kerma-area product for equipment of panoramic radiography, the highest percentage of the equipment was in the range of 60 to 80 mGy cm2. Discussion: The institutions considered to establish the diagnostic reference levels in this study had an adequate quality of the image evaluated with a dental phantom, but the variations in radiation doses between institutions indicate the need to implement tools that contribute to the optimization of the practices. Conclusions: It is recommended to use the values of the diagnostic reference levels found in this research to optimize radiological protection in dental radiological exposures, and it is expected that this study will serve as a basis for further research in other cities of the country.

Protección radiológica en endoscopia

La endoscopía digestiva ha evolucionado de una técnica puramente diagnóstica a un procedimiento terapéutico. Esto es posible en muchos casos gracias al uso de fluoroscopía, lo cual conlleva la exposición a radiaciones ionizantes tanto de los pacientes como del personal actuante. La colangiopancreatografía retrógrada endoscópica (CPRE), que requiere necesariamente de fluoroscopia, es catalogada por la Food and Drug Administration como un examen con potencial riesgo de desencadenar lesiones inducidas por radiación. El presente artículo de revisión repasa los efectos biológicos de las radiaciones, los tipos de equipos radiológicos utilizados en CPRE, así como las magnitudes y unidades dosimétricas, para finalmente abordar los elementos de radio protección en la sala de endoscopia. El objetivo es brindar al lector la informacion para poder realizar estos procedimientos con la mayor seguridad radiológica tanto para los pacientes como para el personal ocupacionalmente expuesto.

Endoscopy has evolved from a purely diagnostic technique to a therapeutic procedure. This is possible in many cases thanks to the use of fluoroscopy, which entails exposure to ionizing radiation for both patients and the personnel involved. Endoscopic retrograde cholangiopancreatography (ERCP), which necessarily requires fluoroscopy, is classified by the Food and Drug Administration as an examination with a potential risk of triggering radiation induced injuries. This article reviews the biological effects of radiation, the types of radiological equipment used in ERCP, as well as the magnitudes and dosimetric units, to finally address the radio protection elements in the endoscopy room. The objective is to provide the reader with the information to be able to perform these procedures with the greatest radiological safety for both patients and occupationally exposed personnel.

Uso de barreras primarias en función del ángulo del gantry en búnker de radioterapia / Uso de barreiras primárias em função do ângulo do gantry em bunkers de radioterapia / Use of primary barriers as a function of gantry angle in radiotherapy bunker

Introducción: el diseño de los búnkeres de radioterapia es de vital importancia no solo por la seguridad radiológica, sino también por el costo que implican. Los cálculos de blindaje de las paredes primarias de los búnkeres de los aceleradores lineales de radioterapia se determinan a partir del factor de uso de estas paredes. Los documentos internacionales como el NCRP 151 utilizan para el cálculo de estas barreras un factor de uso igual a 0.25. Objetivo: estudiar la distribución del uso de las barreras primarias en función de los tratamientos realizados buscando contrastar la homogeneidad en el uso de las barreras. Material y Métodos: con los datos de pacientes realizados durante un año (2021) en dos aceleradores lineales, uno dual y otro monoenergético, se generó una base de datos con la que se calculó la frecuencia de uso de las paredes primarias. En el presente trabajo se evalúa la diferencia entre el uso dado de las barreras y las estimaciones de uso internacional. Resultados: se encuentra que en el acelerador dual en la energía de 15X los campos más usados tienen ángulos de gantry 0º, 90º, 180º, 270º, teniendo un peso acumulado aproximado al 65% al igual que la carga de trabajo para esos ángulos, esto implica que los ángulos diferentes a estos tienen un uso muy inferior al previsto por el cálculo inicial. En el acelerador dual en la energía de 6X el campo más usado es a 0º teniendo un peso aproximado al 14%, pero la carga de trabajo a 0º no se diferencia apreciablemente del resto de los ángulos ya que la distribución no tiene direcciones preferenciales, ninguno de los valores llega a 10% que concuerda con el uso homogéneo de la barrera. En el acelerador monoenergético el peso relativo de los ángulos de 90º y 270º en el uso de las barreras es aproximadamente 34% para cada una, superior al 25% estimado inicialmente. Conclusiones: las barreras primarias de los búnkeres de radioterapia tienen espesores marcados por el cálculo de blindaje, los cuales se pueden hacer basados en documentos internacionales que son referencia del tema. Se considera en las referencias para la barrera primaria un factor de uso igual para las mismas, sin embargo en la práctica clínica se pueden tener un factor de uso no uniforme respondiendo a los tipos de tratamientos que se designen realizar en el equipo. Esta realidad abre la puerta para plantear blindajes optimizados que podrían generar búnkeres más económicos y mejor utilización del espacio de acuerdo a las condiciones dadas para cada caso en particular.

Introduction: The design of radiotherapy bunkers is of vital importance not only for radiation safety, but also for the cost involved. The shielding calculations of the primary walls of radiotherapy linear accelerator bunkers are determined from the use factor of these walls. International documents such as NCRP 151 use for the calculation of these barriers a usage factor equal to 0.25. Objective: to study the distribution of the use of primary barriers according to the treatments performed, seeking to contrast the homogeneity in the use of the barriers. Material and Methods: with the data of patients performed during one year (2021) in two linear accelerators, one dual and the other monoenergetic, a database was generated with which the frequency of use of the primary walls was calculated. The present work evaluates the difference between the given use of the barriers and the estimates of international use. Results: it is found that in the dual accelerator at 15X energy the most used fields have gantry angles 0º, 90º, 180º, 270º, having an accumulated weight of approximately 65% as well as the workload for those angles, this implies that the angles different from these have a use much lower than the one foreseen by the initial calculation. In the dual accelerator at 6X energy the most used field is at 0º having an approximate weight of 14%, but the workload at 0º is not appreciably different from the rest of the angles since the distribution does not have preferential directions, none of the values reaches 10% which is consistent with the homogeneous use of the barrier. In the monoenergetic accelerator, the relative weight of the 90º and 270º angles in the use of the barriers is approximately 34% for each one, higher than the 25% initially estimated. Conclusions: the primary barriers of radiotherapy bunkers have thicknesses marked by the shielding calculation, which can be made based on international documents that are a reference on the subject. It is considered in the references for the primary barrier an equal use factor for them, however in clinical practice they can have a non-uniform use factor responding to the types of treatments that are designed to be performed in the equipment. This reality opens the door to propose optimized shielding that could generate more economical bunkers and better use of space according to the conditions given for each particular case.

Introdução: O projeto de bunkers de radioterapia é de vital importância não apenas para a segurança da radiação, mas também para o custo envolvido. Os cálculos de blindagem para as paredes primárias dos bunkers de aceleradores lineares de radioterapia são determinados com base no fator de uso dessas paredes. Documentos internacionais, como o NCRP 151, usam um fator de uso igual a 0,25 para o cálculo dessas barreiras. Objetivo: estudar a distribuição do uso de barreiras primárias de acordo com os tratamentos realizados, buscando contrastar a homogeneidade no uso das barreiras. Material e métodos: com os dados de pacientes tratados durante um ano (2021) em dois aceleradores lineares, um dual e outro monoenergético, foi gerado um banco de dados com o qual foi calculada a frequência de uso das paredes primárias. Este artigo avalia a diferença entre o uso determinado de barreiras e as estimativas internacionais de uso. Resultados: verifica-se que no acelerador duplo com energia de 15X os campos mais utilizados são os ângulos de pórtico 0º, 90º, 180º, 270º, com um peso acumulado de aproximadamente 65%, assim como a carga de trabalho para esses ângulos, o que implica que os ângulos diferentes desses têm um uso muito menor do que o previsto pelo cálculo inicial. No acelerador duplo a 6X de energia, o campo mais utilizado é o de 0º com um peso aproximado de 14%, mas a carga de trabalho em 0º não é sensivelmente diferente do resto dos ângulos, já que a distribuição não tem direções preferenciais, nenhum dos valores chega a 10%, o que é consistente com o uso homogêneo da barreira. No acelerador de monoenergia, o peso relativo dos ângulos de 90º e 270º no uso das barreiras é de aproximadamente 34% para cada um, superior aos 25% estimados inicialmente. Conclusões: as barreiras primárias dos bunkers de radioterapia têm espessuras balizadas pelo cálculo de blindagem, que pode ser feito com base em documentos internacionais que são referência no assunto. As referências para a barreira primária consideram um fator de uso igual para elas, mas na prática clínica elas podem ter um fator de uso não uniforme, dependendo do tipo de tratamento que o equipamento foi projetado para realizar. Essa realidade abre as portas para uma blindagem otimizada que poderia gerar bunkers mais econômicos e melhor uso do espaço de acordo com as condições dadas para cada caso específico.

Radiation safety measures in diagnostic nuclear medicine, based on the potential radiation dose emitted by radioactive patients / Cuidados de radioproteção em medicina nuclear diagnóstica baseados no potencial de dose de radiação emitida por pacientes radioativos

Abstract Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures.

Resumo Objetivo: O objetivo deste trabalho foi levantar o potencial de dose de radiação emitida por pacientes em procedimentos diagnósticos, visando a estabelecer cuidados de radioproteção mais otimizados. Materiais e Métodos: Taxas de dose de radiação emitidas por 175 pacientes administrados com os radionuclídeos 99mTc, 131I e 18F para cintilografias óssea, renal, cardíaca, cerebral e corpo inteiro, foram mensuradas com um detector de radiação, servindo para avaliar o clareamento do radiofármaco no organismo e risco de exposição após administração dos radiofármacos. Resultados: O clareamento, representado pela meia-vida efetiva, variou de 1,18 ± 0,30 h até 11,41 ± 0,02 h e a dose de radiação máxima acumulada oferecida pelos pacientes a 1,0 m foi de 149,74 ± 56,72 µSv. Mesmo para distâncias de 0,5 m, as doses estimadas foram, respectivamente, duas e dez vezes inferiores ao nível de restrição para o público geral (1,0 mSv) e exposição médica (5,0 mSv/episódio). Conclusão: Doses de radiação oferecidas por pacientes em procedimentos diagnósticos são inferiores aos níveis de restrição recomendados pela International Commission on Radiological Protection e International Atomic Energy Agency, e assim, cuidados de radioproteção são geralmente desnecessários.

A child in radiation examination without protective equipment: A case analysis / 中国辐射卫生

This paper reviews the investigation of examining a child without protective equipment exposed to an exceptionally large radiation field, in order to provide a reference for the investigation and handling of similar cases in the future. Based on the analysis of the way of obtaining evidence and the application of law, the authors put forward some suggestions, such as improving the standards, laws, and regulations related to radiation, enhancing the protective facilities, standardizing the law enforcement procedures, and strengthening the publicity and training of radiation hygiene. The health-related rights and interests of the examinees shall be effectively protected.

A survey of interventional radiology resources and radiation protection equipment and personal dosimeter wearing rate in Qingdao, China / 中国辐射卫生

Objective To investigate the current status of interventional radiology resources, radiation protection equipment, and the rate of wearing of personal dosimeters in Qingdao, China, and to provide a data basis for strengthening radiation protection and health management for interventional radiation workers. Methods A questionnaire survey was performed on all medical institutions with interventional radiation services in Qingdao. The data from April 1, 2020 to March 31, 2021 were pooled and analyzed. Results A total of 31 medical institutions in Qingdao were investigated, including 23 (74.20%) tertiary hospitals and 8 (25.80%) secondary hospitals. There were 88 pieces of interventional radiation equipment in total in Qingdao, 89.77% of which were in tertiary hospitals. A total of 921 interventional professionals participated, with 865 (93.92%) from tertiary hospitals and 56 (6.08%) from secondary hospitals. The mean annual number of visits to interventional services was 5.72 per 1000 people. Among personal protective equipment, the equipment rates of lead-rubber aprons, lead-rubber caps, and lead-rubber collars were highest, all being 100%. The rate of equipment of interventional protective gloves was lowest, which was only 51.61%. The mean number of each accessory protective equipment for each interventional machine was less than 1. The rate of wearing of dual-dosimeters was 84.36%. Conclusion Tertiary hospitals were dominant among the medical institutions in this survey of interventional radiology services in Qingdao. The most frequently equipped personal protective goods were lead-rubber aprons, caps, and collars. The equipment rates of interventional protective gloves and protective accessories and the rate of wearing of dual-dosimeters were relatively low.

Ambient dose equivalent in 99mTcO4- single photon emission computed tomography of the thyroid among patients with hyperthyroidism / 预防医学

Objective@#To investigate the changes of ambient dose equivalent rate in 99mTcO4- single photon emission computed tomography (SPECT) of the thyroid among patients with hyperthyroidism, so as to provide insights into radiation protection guidance.@*Methods@#Patients with hyperthyroidism who underwent 99mTcO4- SPECT of the thyroid in a tertiary hospital were enrolled. The ambient dose equivalent rate was measured at different time points following 99mTcO4- infection and at sites with different distances from patients' neck, and the effects of time post-injection, distance from patients' neck, 24-hour thyroidal radioiodine uptake and thyroid weight on the ambient dose equivalent rate were examined using a generalized linear mixed model.@*Results@#Totally 100 patients with hyperthyroidism were enrolled, including 24 men and 76 women and with a mean age of (38.5±14.0) years. The generalized linear mixed model was statistically significant (F=6 610.165, P<0.001), and patients' thyroid weight, time post-injection and distance from patients' neck significantly affected the ambient dose equivalent rate (F=57.967, 15 988.574, 11 200.645, all P<0.001), and the ambient dose equivalent rate positively correlated with patients' thyroid weight and negatively correlated with time post-injection and distance from patients' neck.@*Conclusions@#The ambient dose equivalent rate is affected by patients' thyroid weight, time post-injection and distance from patients' neck among patients with hyperthyroidism undergoing 99mTcO4- SPECT of the thyroid. Delay in contact with patients or keeping distance from patients may be effective for radiation protection.

Occupational exposure level and requirements for radiation protection of nuclear medical staff / 中华劳动卫生职业病杂志

With the rapid development of nuclear medicine, the number of nuclear medical staff has increased a lot in the past few years in China. Close-range operations, such as preparation and injections of radiopharmaceuticals, are usually carried out in nuclear medicine department. And the use of unsealed radionuclides may also create internal exposure risk. So, occupational exposure of nuclear medical staff is a main issue of occupational health management in China. In this paper, the occupational exposure level and requirements for radiation protection of nuclear medical staff are introduced to provide references for the related work that radiological health technical institutions carry out.

Investigation on awareness of and attitudes towards radiation safety and protective measures among clinical nurses in liver interventional department / 中国辐射卫生

Objective To investigate the awareness of and attitudes towards radiation safety and protective measures among clinical nurses in liver interventional department, so as to provide insights into the formulation of radiation-protective measures among clinical healthcare workers. Methods A cross-sectional study was performed. Clinical nurses in liver interventional departments of class A tertiary hospitals in Jiangsu Province were sampled, and the awareness of and attitudes towards radiation safety and protective measures were investigated using self-designed questionnaires. Results A total of 112 questionnaires were allocated, and 97 valid questionnaires were recovered, with an effective recovery rate of 86.61%. The awareness of questions including “interventional therapy may cause radiation exposure” and “wearing lead apron may reduce radiation exposure” was both 100.00% among respondents, and the awareness of questions including “radiation exposure may cause congenital malformations in babies”, “radiation exposure may cause cancers such as skin cancer and leukemia”, “radiation exposure may cause death”, “wearing lead goggles may reduce radiation exposure”, and “wearing thyroid shields may reduce radiation exposure” was all higher than 95.00%, while the awareness of questions “radiation exposure may cause cataract of the eye lens” and “radiation exposure may cause bone marrow depression” was relatively low. Respondents presented high-level attitudes towards lead aprons, and low-level attitudes towards goggles and thyroid shields. Conclusion The awareness of radiation safety knowledge is high among clinical nurses in liver interventional departments; however, an overall low-level attitude is seen towards radiation-protective measures. Health education pertaining to radiation safety and protective measures is required to be improved, so as to increase the compliance to radiation-protective measures.

Discussion on the evaluation of radiation protection of “four-in-one” dental X-ray equipment / 中国辐射卫生

Objective To evaluate the radiation protection of “four-in-one” dental X-ray equipment and to investigate the safety interlock of the equipment by measuring the scattered radiation at the position of the patient during operation. Methods A cone-beam CT dental phantom was used to simulate the patient’s head. The intra-oral and extra-oral components of the “four-in-one” X-ray equipment were installed in a 5 m2 room. The scattered radiation at patient position was measured using a γ/X-ray survey meter, and the effects of intra-oral and extra-oral components were compared. Results For a 5 m2 room, when CBCT was exposed under typical conditions, the dose at the patient's position was 10.70 uSv/h when there was an intra-oral component and 10.60 uSv/h when there was no intraoral component. The intra-oral part did not affect the radiation dose at the patient's position. When the intra-oral component was exposed, the dose rate at the patient's position was 4.05-6.85 uSv/h, and the extra-oral part did not affect the scattered dose of the patient examined with intra-oral components. Conclusion The evaluation of radiation protection of new equipment must comprehensively consider radiation safety and equipment operation safety. The results of this study provide suggestions for clinical radiation protection supervision and evaluation of “four-in-one” dental X-ray equipment.

Response of radioactivity meter in vertical direction of ionization chamber / 中国辐射卫生

Objective To determine the responses of radioactivity meter at different positions in the vertical direction of the ionization chamber by measuring different radioactive sources. Methods The radiation of cesium-137, cobalt-60, and americium-241 nuclides was measured at different positions in the vertical direction of the ionization chamber with commonly used clinical radioactivity meters. The measured values were fitted to obtain three trend lines. The maximum deviation of the measured values was estimated according to the trend line, and the deviation was estimated at different syringe needle heights. Results According to the trend lines, the maximum deviation of the radioactivity meter CRC-55tR in measuring cesium-137, cobalt-60, and americium-241 nuclides was 5.15%, 5.98%, and 6.25% respectively. The radioactivity meter RM-905a was used to measure three nuclides at different syringe needle heights, and the maximum deviations were −4.33%, −9.9%, and −12.65%, respectively. Conclusion The three nuclides showed different change patterns in measurement with CRC-55tR and RM-905a but similar change patterns in measurement with the same radioactivity meter. The values measured with the same radioactivity meter showed significant deviations at different positions in the vertical direction of the ionization chamber. It is recommended to make position correction for commonly used nuclides. Reducing measurement error and improving measurement accuracy of nuclides are of great significance for radiation protection.

Research progress of cell death in radiation protection and radiosensitization / 中国辐射卫生

@#The rapid advances in technology and medicine have greatly facilitated the application of ionizing radiation. Clinically, radiotherapy is one of the major treatments for malignant tumors. However, besides killing tumor cells, ionizing radiation inevitably leads to radiation damage and even death of normal cells. How ionizing radiation causes cell death and the forms of cell death have always been important research topics in this field. Recently, several forms of cell death induced by irradiation have been discovered. Apart from apoptosis, pyroptosis, necroptosis, ferroptosis, autophagic cell death, and methuosis have gradually become research hotspots, and provide new targets for the development of radioprotective drugs and radiosensitizers. In this review, we summarize various forms of ionizing radiation-induced cell death and related molecular mechanisms. We also introduce the latest progress in radiation protection and radiosensitization based on these cell death mechanisms. This review will provide a reference for the research and development of radioprotective drugs and radiosensitizers in the future.

Experience in radiation protection management in the tertiary general hospital / 中国辐射卫生

@#With widespread popularization, the radiological diagnosis and treatment technology has played an increasingly important role in clinical practice. The tertiary general hospital is generally featured as multiple types of radioisotope and radiation equipment, wide involvement of departments and persons, and many ways of use and potential harms of the radiological diagnosis and treatment technology. Radiation protection has become a content that cannot be ignored in hospital management. This article analyzes the radiation protection management structure of the tertiary general hospital - Guangdong Provincial People’s Hospital. The hospital radiation protection management is gradually improved by clarifying the main leading department, refining duties and responsibilities, strengthening multi-departmental communication and cooperation, and sorting out key connection links. A closed loop of refined management is formed through digging and correcting problems and continuously improving the management level and work efficiency. Valid qualifications are ensured to be obtained in time by radiation workers, radioactive drugs, equipment, and the venues to guarantee the radiation safety of radiation workers and patients and to further promote the construction of the Safe Hospital.

Influence of radiation protection on layout of fuel reprocessing plant and countermeasures / 中国辐射卫生

@#Radiation protection is an important requirement in the design of spent nuclear fuel reprocessing plant. The design of all main process plants should consider the impact of radiation on staff and environment, while radiation protection is not required in the design of general industrial and civil buildings. This difference puts forward higher requirements for the architectural design of spent nuclear fuel reprocessing plant. From the perspective of architectural design, this paper analyzed the differences between spent nuclear fuel reprocessing plant and ordinary plant, as well as the compatibility of radiation protection requirements and current architectural design specifications. We proposed corresponding countermeasures based on our engineering experience, and summarized important design principles related to radiation protection requirements, which can be used as a reference by architectural designers in designing spent nuclear fuel reprocessing plants.

Research progress of epigallocatechin gallate in radiation protection / 中国辐射卫生

Epigallocatechin gallate (EGCG) is a major polyphenol component in green tea. EGCG has high free radical scavenging activity, radiation protection efficiency, and metal-chelating capacity due to its unique structure with hydroxyl groups. EGCG and its derivatives have been reported in various fields. This paper reviews the effects of EGCG, including radiation protection, heavy metal ion adsorption, and promotion of heavy metal ion excretion. EGCG has the potential to be used as an ideal radiation protection agent, heavy metal adsorbent, and even excretion promoting agent.

Health hazards and protective measures of medical radiation / 中国辐射卫生

Ionizing radiation has been widely used for diagnosis and treatment of diseases. Nevertheless, radiation exposure may increase the risk of skin, cardiovascular system, hematological system, and metabolic disorders, and even the risk of cancers. Rational use of ionizing radiation improves prognosis and facilitates biomedical research, while misuse or overuse may result in serious consequences. Scientific and objective assessment of health hazards of medical radiation and establishment of effective protective interventions are of great importance to control the risk of radiation exposure. This article reviews the health hazards and protective measures of medical radiation.

Radiation safety analysis of retrieval and conditioning of naturally occurring radioactive material waste / 中国辐射卫生

Objective The radioactivity level in historical waste from a plant is high, and decommissioning operators may be exposed to high radiation doses. The objective of the study is to carry out a radiation safety analysis of the retrieval and conditioning of naturally occurring radioactive material (NORM) waste, put forward appropriate radiation protection measures, and minimize the exposure doses of operators. Methods The source terms of NORM waste in the temporary storehouse were analyzed; MicroShield, a point kernel integration program, was used for modeling and calculation; and radiation protection measures under decommissioning conditions were put forward based on on-site monitoring data. Results The maximum gamma dose rate calculated near the waste pile in the temporary storehouse was 313.9 μGy/h, equivalent to the monitoring level; distance decay and appropriate shielding measures significantly reduced gamma dose rates for operators. Conclusion Decommissioning sites of temporary storehouses are of great harm to operators. Measures such as shielding, isolation, remote operations, and personal protection can effectively reduce the exposure doses of operators.

Challenge of shielding design for FLASH radiotherapy / 中华放射医学与防护杂志

Compared with conventional radiotherapy, FLASH radiotherapy has advantages in protecting normal tissues, while the dose rate is increased by more than 100 times. If the shielding design of the treatment room is carried out according to the existing standard, the thickness and cost of the shielding wall will be significantly increased, or even hardly to meet the requirement of the standards, resultsing in the failure of the application of FLASH radiotherapy. By investigating the domestic and foreign standards and literature, this paper analyzes the challenges brought by FLASH radiotherapy technology to the shielding design of radiotherapy treatment room in China. Dose rate control standards adopted by different countries in the shielding design are emphatically compared as well. In several countries, the average dose rate under the actual treatment conditions was considered in the shielding design. In China, the method of instantaneous dose rate taking acount of occupancy factor is adopted. However, if FLASH radiotherapy technology is applied, the requirement of instantaneous dose rate will be difficult to meet. In order to improve the high dose rate radiotherapy technology such as FLASH radiotherapy, the revision of the existing standards is advised if the authorized limits are not changed. To use the average dose rate limit within a certain period of time for control, or to raise the control standard in the case of flash radiotherapy, are also avaliable.

Analysis of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice / 中华放射医学与防护杂志

Objective:To elucidate the change of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice.Methods:C57BL/6J male mice were administrated with melatonin at 10 mg/kg body weight by intraperitoneal injection once a day for five consecutive days before abdominal irradiation with 14 Gy of γ-rays. Small intestines were harvested 3 d after radiation. GO annotation and KEGG pathway of the differential genes involved in small intestine were explored by DNA microarray analysis.Results:Compared with the control group, 584 differential genes were up-regulated and 538 differential genes were down-regulated for administration group pre-irradiation. The overlapping differential genes were selected from the irradiated mice and the administrated mice pre-irradiation. There were 324 up-regulated genes and 246 down-regulated genes unique to the administrated mice pre-irradiation. GO annotation analysis of the differential genes indicated that the top 15 significantly enriched biological processes for the administrated mice pre-irradiation mainly included autophagosome assembly (GO: 0000045), autophagosome organization (GO: 1905037) and regulation of acute inflammatory response (GO: 0002673). The genes ATG12, ATG16L2 and AMBRA1 were involved in autophagosome assembly and autophagosome organization. The genes C3, CPN1, CD55, CFP, CNR1, C1QA, C2 and CREB3L3 were involved in the regulation of acute inflammation response. KEGG pathway analysis of the differential genes involved indicated that the top 15 significantly enriched pathways for the administrated mice pre-irradiation mainly included O-glycan biosynthesis (hsa00512), glycosphingolipid biosynthesis (hsa00603), ECM-receptor interaction (hsa04512) and biosynthesis of unsaturated fatty acids (hsa01040). qRT-PCR verification showed that the expressions of ATG12 and ATG16L2 genes involved in autophagy for the administrated mice pre-irradiation increased significantly compared with the irradiated mice ( t=2.40, 4.35, P<0.05). Conclusions:The differential genes related with the biological process of autophagy, acute inflammatory response and the pathway of unsaturated fatty acid biosynthesis might be involved in the effect of melatonin on radiation-induced intestinal injury.