Research progress on radiobiological effects of ferroptosis in cancer / 中华放射肿瘤学杂志

Ferroptosis is a new form of regulated cell death discovered in recent years, which is iron-dependent cell death characterized by peroxidation of polyunsaturated fatty acid phospholipids. Recent studies have shown that radiotherapy can induce ferroptosis in cancer cells via ionizing radiation. Targeting ferroptosis plays a synergistic role in tumor suppression with radiation, which not only further deepens the connotation of radiobiology, but also provides a new perspective for tumor radiosensitization. This review systematically summarizes the occurrence and defense of ferroptosis, focusing on the key role of ferroptosis in the radiobiological effects of tumor cells and the potential application of ferroptosis in radiosensitization.

Dosimetry standardization in radiobiological research / 中华放射肿瘤学杂志

In recent years, the issue of "reproducibility" of scientific research results has become more and more prominent. Radiobiology is a medical science that studies the biological effect of radiation on living organisms, and there is also a serious problem of "reproducibility of findings". Inaccuracy of physical dose or incomplete dosimetric reports is one of the main causes. Use of guidelines, specifications and recommendations for dosimetric measurement, such as the standardized scoring system for dosimetric reports, will help improving the standardization and accuracy of physical dose measurement in radiobiological research. In this article, multiple guidelines and recommends for improving collaboration between radiobiology and radiation physics, as well as for dose standardization of radiobiological research were evaluated, aiming to provide reference for improving the reproducibility of radiobiological research.

Current situation investigation on the standardization of physical dose description in radiobiology researches in China / 中华放射医学与防护杂志

Objective:To understand the normative status of physical dose description in domestic radiobiology studies through literature study.Methods:According to the scoring system recommended by the National Cancer Institute (NCI) and Desrosiers et al, evaluate (full Score: 10 points) the normalization of physical dosimetry description in the radiobiology-related articles published in two important journals, Chinese Journal of Radiation Oncology and Chinese Journal of Radiological Medicine and Protection, in past 5 years.Results:A total of 222 relevant articles from these two journals were included, and a median score of 5.0 was evaluated. Among them, 72.1% of the literatures scored 4.0-7.0 points, 68.0% of the literatures scored ≤5.5 points, and 18.5% scored ≤3.0 points. 90.1% and 97.7% of the literatures described " the type of ray" and " absorbed dose" , with the highest average score (0.90 and 0.98 points) respectively. The lowest average score of " dosimetry calibration" was 0 point.Conclusions:Although the most of literatures described " the type of ray" and " absorbed dose" , most other details of dosimetric parameters were not reported. Therefore, there is a deficiency in the standardized description of physical dosimetry in domestic radiobiology literatures, which may affect the reproducibility and interpretability of research result.

Effect analysis of BOPPPS model in online teaching activities of radiobiology / 中华放射医学与防护杂志

Objective:To explore the effect of a new teaching mode, which includes bridge-in, outcome, pre-test, participation, post-test and summary (BOPPPS), on the online teaching of radiobiology related knowledge for cancer radiotherapy practitioners.Methods:Taking the cell survival curve, cell cycle and radiosensitivity as examples, the radiotherapy practitioners in multiple university-affiliated hospitals were organized to carry out a multicenter prospective randomized control study. All practitioners were randomly divided into BOPPPS group and control group. The courses for BOPPPS group were designed as an online classroom, consisting of pre-class preparation, online teaching and post-class stages. The online teaching stage included video viewing, basic knowledge learning, literature discussion, group discussion and others. The control group employed the traditional teaching mode. The χ2 test was used to compare the consistency of general conditions between the two groups, and nonparametric test was used to compare the differences in scores between two or more groups. Results:The score of the pre-class test was 58.56 ± 0.99. Post-class average score for BOPPPS group was 85.48±0.85 and for control group 77.79±1.10, with the former being higher 7.69 ( Z=5.31, P<0.001) than the latter. The average answer time was (296.62±15.40) s for BOPPPS group and (386.41±21.27) s for control group, with the former being shorter 89.79 s ( Z=3.34, P=0.001) than latter. Subgroup analysis shown that the scores of BOPPPS group were significantly rising, regardless of whether or not the students had studied radiobiology courses. Among the students who have not studied these courses, the scores were rising greatly. Moreover, From the analysis of different positions, it was found that both the scores of BOPPPS group and control group have risen, especially for doctors, deputy chief doctors, physicists and technicians. There were also statistically differences between different degrees, with significantly rise in scores for undergraduate and doctoral students ( Z=3.64, 4.18, P<0.001). Conclusions:The flexible application of BOPPPS teaching mode to the online education of such boring disciplines, like radiobiology, is of great significance to raise the theoretical basis of radiotherapy practitioners.

Radioterapia en cáncer de la región maxilofacial / Radiation therapy in cancer of the maxillofacial region

RESUMEN Introducción: La Radiobiología es la ciencia perteneciente a la biología que estudia los efectos de los distintos tipos de radiación sobre la materia viva. Objetivo: Identificar la evidencia científica respecto a la radioterapia del paciente con cáncer en la región maxilofacial. Métodos : Se realizó una revisión de la de literatura acerca del tema en motores de búsqueda como: las bases de datos electrónicas PubMed, Medline, Cochrane, Hinari y SciELO. Para la búsqueda de la información se utilizaron las palabras clave: cáncer de cabeza y cuello, tratamiento del cáncer de la región maxilofacial, radioterapia, braquiterapia y tipos de radioterapia. Resultados: Para el tratamiento se necesita evaluar las características del tumor y determinar el estadio tumoral, la localización y extensión de la enfermedad, así como los hallazgos patológicos que dictan la conducta adecuada como la cirugía, radioterapia, quimioterapia, terapia hormonal, inmunoterapia y terapia dirigida. La dosis máxima tolerada en relación con los órganos críticos oscila entre 50 y 76 Gy. Con la braquiterapia se puede colocar la fuente radiactiva dentro del paciente en cavidades anatómicas cerca del tumor o en el lecho tumoral. Esto permite administrar dosis elevadas de irradiación muy eficaces, al tumor o zona de riesgo. Los efectos adversos de las radiaciones ionizantes según la célula afectada pueden ser daño genético y somático. Conclusiones: En el tratamiento del cáncer la radioterapia es una opción primordial, siempre con el precepto que ofrezca buenos resultados en cuanto a eficacia, tolerabilidad y calidad de vida, al causar el menor daño posible a los enfermos y con las nuevas tecnologías puede incrementar el éxito y garantizar que el procedimiento continúe con calidad.

Introduction: Radiobiology is the science belonging to the biology that studies the effects of the different types of radiation on the lively matter. Objective: Identifying the scientific evidence in relation to radiation therapy of the patient with cancer of the maxillofacial region. Methods: A literature revision was carried out in search engines as: The electronic data bases PubMed, Medline, Cochrane, Hinari, and SciELO. For the search for information the key words used were head and neck cancer, treatment of the cancer of the maxillofacial region, radiation therapy, brachytherapy and types of radiation therapy. Results: For the treatment it is needed to evaluate the characteristics of the tumor and to determine the tumor stage, the location and extension of disease, as well as the pathological findings that dictate the conduct made suitable like the surgery, radiation therapy, chemotherapy, hormonal therapy, immunotherapy and directive therapy. The maximum dose tolerated relating to the critical organs oscillates between 50 and 76 Gy. With the brachytherapy the radioactive source inside the patient can place itself in reservoirs, close to the tumor or in the tumor area. This allows managing dose lifted of irradiation very effective, to the tumor or zone of risk. The adverse effects of the ionizing radiations according to the impaired cell can be genetic and somatic damage. Conclusions: In the treatment of cancer, radiation therapy is a primary option, always with the precept that offers good results as to efficacy, tolerance and quality of life, causing the smaller possible damage to the sick and with the new technologies it can increase success and guarantee that a procedure keeps on being high-quality.

Protección Radiológica en Radiología Dental / Proteção Radiologica em Radiologia Dentária / Radiation Protection in Dental Radiology

Resumen El uso de rayos X juega un papel esencial en el diagnóstico y planificación de tratamientos dentales. Los avances tecnológicos de los equipos de rayos X han contribuido al mayor uso de este tipo de radiación en la práctica odontológica. Aunque la exposición a la radiación es baja en estos procedimientos, todavía existe un riesgo que debe reducirse al mínimo necesario a fin de obtener una imagen adecuada para el diagnóstico y a la vez evitar efectos nocivos para el paciente y el personal involucrado. Debido al alto y creciente número de radiografías dentales, el hecho de que niños y adolescentes sean el foco de la mayoría de estas, la subestimación de la cantidad de exámenes radiológicos reportados y la supuesta baja conciencia de estudiantes y profesionales de la odontología sobre los peligros del uso indiscriminado de los rayos X, es necesario adoptar medidas de protección radiológica para mitigar los efectos biológicos radioinducidos. Este artículo tiene como objetivo revisar los principios básicos de la radioprotección que deben considerarse en la práctica dental, con el fin de garantizar el menor daño posible a trabajadores ocupacionalmente expuestos, pacientes y miembros del público.

Resumo O uso dos raios X desempenha um papel essencial no diagnóstico e planejamento de tratamentos dentários. O avanço tecnológico nos equipamentos de raios-X tem contribuído para o aumento do uso deste tipo de radiação na prática odontológica. Embora a exposição à radiação seja baixa nestes procedimentos, ela representa um risco e deve ser reduzida ao mínimo valor necessário para se obter a imagem adequada para o diagnóstico, evitando efeitos nocivos ao paciente e ao pessoal envolvido. Devido ao elevado e crescente número de radiografias odontológicas, ao fato de crianças e adolescentes serem o foco de grande parte delas, a subestimação do número de exames radiológicos notificados e a suposta baixa conscientização de estudantes e profissionais da odontologia sobre os perigos dos uso indiscriminado de raios-x, é precisa a adoção de medidas de radioproteção para mitigar o risco de efeitos nocivos radioinduzidos. Este artigo tem como objetivo revisar os princípios básicos da radioproteção a serem considerados na prática odontológica, a fim de garantir o menor prejuízo possível para trabalhadores ocupacionalmente expostos, pacientes e membros do público.

Abstract The use of X-rays plays an essential role in the diagnosis and planning of dental treatments. Technological advances in X-ray equipment have contributed to the increased use of this type of radiation in dental practice. Although radiation exposure is low in these procedures, there is still a risk. The reduction of the risk to the minimum value possible is necessary to obtain an adequate image for the diagnosis and avoiding harmful effects on the patient and the personnel involved. Due to the high and growing number of dental X-rays, the fact that children and adolescents are the focus of most of them, the underestimation of the number of radiological examinations reported and the supposed low awareness of dental students and professionals about the dangers the indiscriminate use of X-rays, it is necessary to adopt radioprotection measures to mitigate the risk of harmful radioinduced effects. This article aims to review the basic principles of radioprotection to be considered in dental radiology, in order to ensure the least possible damage to occupationally exposed workers, patients and public members.

Application of FLASH radiotherapy with an ultra-high dose rate in malignant tumor / 中华放射医学与防护杂志

As a method for local treatment, radiotherapy plays a key role in the management of tumors. In the past few decades, great progress has been made in radiotherapy technology, with improvements in conformity, homogeneity, and radiotherapy efficiency, and the results are encouraging. Nevertheless, the maximum tolerated dose of normal tissue has limited the further increase in radiotherapy dose in the tumor area. If radiation-induced toxicities can be reduced, a higher radiotherapy dose can be delivered to tumor tissue, so as to achieve a better treatment response. In recent years, the unique FLASH effect of ultra-high-dose-rate radiotherapy (FLASH-RT) is capable of maintaining a consistent tumor response whilst reducing radiation-induced toxicities in normal tissue, and therefore, FLASH-RT has become a research hotspot in the field of radiotherapy across the world. At present, some scholars tend to explain the FLASH effect using the theory of acute oxygen depletion, but the protective effect of FLASH-RT on normal tissue remains to be clarified. In addition, preliminary clinical studies have been conducted for FLASH-RT, and the results are promising. Based on existing evidence, this article elaborates on the research advances in FLASH-RT in the treatment of malignant tumor, so as to provide a reference for the translation and application of this new technique.

The Potential of Gallic Acid as a Radiosensitizer on Human Prostate Cancer: A Systematic Review of Preclinical Studies

@#Prostate adenocarcinoma accounts for majority of prostate cancer cases, and it was found to be highly radioresistant. Gallic acid is a phenolic acid naturally occurring in many plants, reported to exhibit biological activities in eliminating cancer cell lines and xenografts. The purpose of this study is to review gallic acid as a potential radiosensitizer agent in prostate cancer treatment. Article search was conducted in PubMed, EBSCO, and Scopus. 11 studies using different cell lines including DU145, PC-3, LNCaP, and 22Rv1 xenograft of human prostate cancer were reviewed in this paper. Gallic acid acts as a radiosensitizer mainly by increasing caspase-3 and caspase-9 activation resulting in apoptosis, while also reducing intracellular CDKs, cyclins, and cdc25 phosphatases ultimately causing G2-M cell cycle arrest. Gallic acid has a potential to be a new radiosensitizer compound in prostate cancer treatment. Additional clinical studies using gallic acid derivatives with lower hydrophilicity are needed.

Interpretation of ICRU Report No.89 (prescribing, recording, and reporting brachytherapy for cancer of the cervix)—radiobiology / 中华放射肿瘤学杂志

This paper made a detailed interpretation about the radiobiology-related contents in the ICRU report No.89,aiming to provide reference to resolve the problems related to radiobiology for the colleagues occupied in the brachytherapy for cervical cancer.

Dose-response relationship of radiation-induced pulmonary fibrosis in mouse models based on CT-derived parameters / 中华放射肿瘤学杂志

Objective To investigate the radiation induced pulmonary fibrosis with a dose-response mouse model, based on the CT image changes of pulmonary fibrosis.Methods Female C57BL6 mice aged 8-10 weeks were randomly divided into 20 Gy or escalated doses of X-ray whole thoracic irradiation ( WTI) groups. CT scan was performed at different time points before and after radiation. The average lung density and lung volume changes were obtained by three-dimensional segmentation algorithm. After gene chip and pathological validation, the parameters of CT scan were subject to the establishment of logistic regression model. Results At the endpoint of 24 weeks post-irradiation, the lung density in the 20 Gy irradiation group was (-289.81± 12.06) HU, significantly increased compared with (-377.97± 6.24) HU in the control group ( P<0.001) . The lung volume was ( 0.66±0.01) cm3 in the control group, significantly larger than ( 0.44±0.03) cm3 in the irradiated mice ( P<0.001) . The results of quantitative imaging analysis were in accordance with the findings of HE and Mason staining, which were positively correlated with the fibrosis-related biomarkers at the transcriptional level ( all R2=0.75, all P<0.001) . The ED50 for increased lung density was found to be ( 13.64± 0.14) Gy ( R2=0.99, P<0.001) and ( 16.17± 4.36) Gy ( R2=0.89, P<0.001) for decreased lung volume according to the logistic regression model. Conclusions Quantitative CT measurement of lung density and volume are reliable imaging parameters to evaluate the degree of radiation-induced pulmonary fibrosis in mouse models. The dose-response mouse models with pulmonary fibrosis changes can provide experimental basis for comparative analysis of high-dose hypofractioned irradiation-and half-lung irradiation-induced pulmonary fibrosis.

Clinical radiobiology of brachytherapy / 中华放射医学与防护杂志

Brachythrapy is a technique to implant radioactive isotype into or near tumors.The obvious properties of brachytherapy are a very high dose distribution of center,and rapid dose attenuation with the increasing of distance.Brachytherapy generally includes three major categories:low dose rate,high dose rate and pulse dose rate.The most significant clinical value of brachytherapy is that it could create dose distribution to tumor tissues,but decreased radiation injury of normal tissues close to tumor.The development of the clinical brachytherapy technique is always involved in the radiobiological characteristics.The basic concepts involving clinical brachytherapy radiobiology mainly includes:dose-rate effect,repair of radiation injury,re-oxygenation,cell cycle redistribution and repopulation.An amount of translational medical approach is needed to guide the application of clinical brachytherapy by exploring the interaction between brachytherapy radiobiology and clinical brachytherapy effect,as well as taking advantage of brachytherapy radiobiological characteristics.The ultimate goal is to improve tumor local control rate,reduce the occurrence of adverse reactions,and improve patients' overall survival.

The challenges of precision radiotherapy technology to the traditional theory of radiobiology / 中华放射医学与防护杂志

With the development of modern computing technology and medical physics,radiotherapy has made great progress.The theoretical basis of radiobiology seems to lag behind the clinical application of radiotherapy,which hampers the further improvement of treatment efficacy and the optimization of treatment modality.In this paper,some emerging challenges of precision radiotherapy technology to the traditional theory of radiobiology,such as radiosensitivity,dose-response curve and survival curve,linear-quadratic model,4Rs theory,as well as the interaction between cancer and microenvironment,radiation-induced second primary cancers (RISPC),will be discussed.The interplay between precision radiotherapy and traditional radiobiology theories will be addressed with the aim to potentially solve some of the challenging problems.

Novel biological strategies to enhance the radiation therapeutic ratio

Successful anticancer strategies require a differential response between tumor and normal tissue (i.e., a therapeutic ratio). In fact, improving the effectiveness of a cancer therapeutic is of no clinical value in the absence of a significant increase in the differential response between tumor and normal tissue. Although radiation dose escalation with the use of intensity modulated radiation therapy has permitted the maximum tolerable dose for most locally advanced cancers, improvements in tumor control without damaging normal adjacent tissues are needed. As a means of increasing the therapeutic ratio, several new approaches are under development. Drugs targeting signal transduction pathways in cancer progression and more recently, immunotherapeutics targeting specific immune cell subsets have entered the clinic with promising early results. Radiobiological research is underway to address pressing questions as to the dose per fraction, irradiated tumor volume and time sequence of the drug administration. To exploit these exciting novel strategies, a better understanding is needed of the cellular and molecular pathways responsible for both cancer and normal tissue and organ response, including the role of radiation-induced accelerated senescence. This review will highlight the current understanding of promising biologically targeted therapies to enhance the radiation therapeutic ratio.

Research progress in proton in oncology radiobiology / 中华放射肿瘤学杂志

Proton is formed after hydrogen atom loses an electron with a positive charge of particle (H+ ). After the proton is accelerated, it possesses significant advantages in terms of the distribution of physical dose compared with the photon. Currently, proton radiation has captivated extensive attention and has been actively applied in clinical practice. Nevertheless, due to the small amount of proton facilities and lack of clinical trials, the proton therapy, especially the radiobiological characteristics and biological effect of photon radiotherapy has been poorly understood. In this article, these issues were summarized as below.

Hotspots of stereotactic body radiotherapy in radiobiology / 中华放射肿瘤学杂志

Stereotactic body radiotherapy ( SBRT) has been gradually proven to be effective in treating multiple solid tumors. Along with the development of image-guided radiotherapy (IGRT) system and radiotherapy,SBRT can form a high-dose region in the target area,whereas the dose gradient outside the target area declines rapidly. It not only delivers large-dose irradiation to the tumors,but also protects the surrounding normal tissues as possible,thereby implementing safe" big fractionated radiotherapy" .At present, regular understanding of the radiobiology underlying SBRT is still lacking. Multiple issues, such as applicability of linear quadratic ( LQ) model, weakening of re-oxygenation, additional cell killing effect different from conventional fractionated radiotherapy and immune enhancement effect are still controversial. In this article,the above controversial hotspots were discussed and analyzed,aiming to deepen the understanding of the radiobiological characteristics of SBRT and contribute to promoting the application of SBRT in clinical practice.

Proteção radiológica: conhecimento e métodos dos cirurgiões-dentistas / Radiological protection: knowledge and methods of dentist

Objetivo: Avaliar o conhecimento de cirurgiões-dentistas da cidade de Patos-PB acerca da biossegurança em radiologia odontológica e métodos de proteção utilizados. Métodos: Foi utilizada uma abordagem indutiva com procedimento estatístico descritivo e técnica de documentação direta através da pesquisa de campo, utilizando o formulário como instrumento. Participaram do estudo 50 cirurgiões-dentistas que trabalhavam em consultórios particulares com aparelho de raios X intraoral na cidade de Patos-PB. Após a assinatura do Termo de Consentimento Livre e Esclarecido pelos profissionais, foram aplicados questionários para avaliação do conhecimento dos mesmos sobre biossegurança em radiologia e práticas de proteção utilizadas. Os dados foram tabulados e foi feita análise descritiva das variáveis qualitativas pelas medidas de proporção, frequências e porcentagens. Resultados: Observou-se que todos os profissionais mostraram preocupação em relação à radioproteção e que buscavam realizar os exames radiográficos seguindo os princípios de cada técnica radiográfica a fim de se evitar a repetição das mesmas. Para proteção do paciente, a maioria relatou utilizar avental de chumbo, incluindo protetor de tireóide, além de reduzir o tempo de exposição. Acerca da proteção própria, a maior parte afirmou possuir paredes com revestimento de chumbo. Conclusão: Observouse que a maioria dos profissionais tem conscientização acerca dos aspectos de radioproteção, contudo, alguns cirurgiões-dentistas ainda desconhecem os mesmos e não praticam a biossegurança em radiologia, colocando em risco sua própria saúde e a dos pacientes.(AU)

Aim: To assess the knowledge of dentists in the city of Patos, PB, Brazil, about biosafety in radiology and applied protection methods. Methods: This study involved an inductive approach with a descriptivestatistical procedure and a research technique for direct documentation in the field, using a questionnaire as the main instrument. This study included 50 dentists who work in private practices with intraoral X-ray units in Patos, PB. After the professionals had signed the Free and Informed Consent Form, questionnaires were applied to evaluate the dentists' knowledge about biosafety in radiology and their protection practices. The data were tabulated, and a descriptive analysis was performed regarding the qualitative variables measured by proportion, frequencies, and percentages. Results: It was observed that all of the staff were concerned about their own radioprotection and that they sought to comply with the principles of each radiographic technique in order to avoid repeating radiographs. For patient protection, the majority reported using lead aprons, including a thyroid shield, in addition to reducing exposure time. Regarding their own protection, most facilities have walls with lead casing. Conclusion: It was observed that most professionals are aware of the aspects of radiological protection; however, some are still unfamiliar with these procedures and do not practice biosafety in radiology, putting their own health and that of their patients at risk.(AU)

Is the Linear No-Threshold Dose-Response Paradigm Still Necessary for the Assessment of Health Effects of Low Dose Radiation?

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.

Evolving Clinical Cancer Radiotherapy: Concerns Regarding Normal Tissue Protection and Quality Assurance

Radiotherapy, which is one of three major cancer treatment methods in modern medicine, has continued to develop for a long period, more than a century. The development of radiotherapy means allowing the administration of higher doses to tumors to improve tumor control rates while minimizing the radiation doses absorbed by surrounding normal tissues through which radiation passes for administration to tumors, thereby reducing or removing the incidence of side effects. Such development of radiotherapy was accomplished by the development of clinical radiation oncology, the development of computers and machine engineering, the introduction of cutting-edge imaging technology, a deepened understanding of biological studies on the effects of radiation on human bodies, and the development of quality assurance (QA) programs in medical physics. The development of radiotherapy over the last two decades has been quite dazzling. Due to continuous improvements in cancer treatment, the average five-year survival rate of cancer patients has been close to 70%. The increases in cancer patients' complete cure rates and survival periods are making patients' quality of life during or after treatment a vitally important issue. Radiotherapy is implemented in approximately 1/3 to 2/3s of all cancer patients; and has improved the quality of life of cancer patients in the present age. Over the last century, as a noninvasive treatment, radiotherapy has unceasingly enhanced complete tumor cure rates and the side effects of radiotherapy have been gradually decreasing, resulting in a tremendous improvement in the quality of life of cancer patients.

Research of Radiosensitizing Effect of Flavonoids under Hypoxia / 中国药师

Objective:To investigate the radiosensitizing effect of three flavonoids on ovarian cancer SKOV3 cells under hypoxia. Methods:The SKOV3 cells were divided into normoxic group and hypoxic group. The hypoxic SKOV3 cellular model in vitro was es-tablished and tested by measuring the expression profile of HIF-1αprotein in SKOV3 cells. Colony-forming assay was used to detect the radiosensitivity of normoxic and hypoxic SKOV3 cells. The cytotoxicity and radiosensitizing effects of flavonoids were evaluated on the basis of cell death and MTT assay. Results:The Western blot results showed that the gray intensity ratio of HIF-1α/β-Actin in hypoxia group was significantly higher than that in normoxia group (1. 068>0. 117). Radiosensitivity of hypoxic SKOV3 cells in hypoxia group was significantly lower than that in normoxia group. The survival rate of SKOV3 cells was decreased with the increase of concentration. When the concentration was increased, D0 and Dqin chrysin group and quercetin group were significantly decreased (P0. 05). The overall radiobiological parameters of hypoxia group were higher than those of normoxia group. Conclusion: Hypoxia can induce the expression of HIF-1α in SKOV3 cells, which results in the decrease of radiosensitivity. Chrysin and quercetin can enhance the radiosensitivity of SKOV3 cells, and the enhancement is significant under hypoxia, while breviscapine is without such effect. The radiosensitizing effect may be achieved by the level decrease of HIF-1α in SKOV3 cells and inhibition of DNA damage repair.

Riesgos de la radiación en imágenes pediátricas / Radiation risks in pediatric images

The advance of medical imaging technology has led to an increase in the medical radiation exposure, especially derived from computed tomography (CT). Recent studies confirm a small but significant increase of cancer cases induced by CT radiation. Children are markedly more sensitive to radiation than adults and in addition, their life expectancy is longer, so we must use all resources to optimize and reduce the exposure dose using the ALARA concept. CT is an important diagnostic tool in medical practice and its benefits far outweigh the costs of radiation if the indication is properly justified.

El avance tecnológico de las imágenes para evaluación de enfermedades ha llevado a un aumento considerable de la radiación de origen médica, principalmente la proveniente de la tomografía computada (TC). Estudios recientes confirman un pequeño pero significativo incremento de casos de cáncer inducidos por radiación generada por la TC. Siendo los niños reconocidamente más sensibles a la radiación que los adultos y sumado a su mayor expectativa de vida, es que debemos usar todos los recursos para optimizar y reducir la dosis de exposición aplicando el concepto de ALARA. La TC es una herramienta diagnóstica importantísima en la práctica médica, y sus beneficios superan ampliamente los costos de la radiación si su indicación está adecuadamente justificada.