Medical physics graduate education in Mexico and its relation to the advances in radiation oncology

AimTo evaluate the state of graduate education in medical physics and progress in radiation oncology (RO) equipment in Mexico since 2000, when conferring degrees from two master’s-degree programs in Medical Physics began.BackgroundMedical physics is a Health Profession and there are international recommendations for education, training, and certification. Both programs follow these education guidelines. The most common clinical occupation of graduates is in RO services. Techniques in Mexican RO include traditional and high-precision procedures.MethodsAcademic and occupational information about the programs and their graduates were obtained from official websites. Graduates were invited to respond to a survey that requested information about their present job. We obtained data on RO equipment and human resources from public databases and estimated staffing requirements of medical physicists (MPs).ResultsMedical physics programs have graduated a total of 225 MPs. Half of them work in a clinical environment and, of these, about 90 work in RO services. MPs with M.Sc. degrees constitute 36% of the current MP workforce in RO, estimated to be 250 individuals. Survey responses pointed out the main merits and limitations of the programs. The number of MPs in RO has increased fivefold and the number of linacs sixfold in 15 years. The present number of MPs is insufficient, according to published guidelines.ConclusionAll MPs in RO services with advanced modalities must be trained following international recommendations for graduate education and post-graduation clinical training. Education and health institutions must find incentives to create more graduate programs and clinical residencies.     

Critical success factors for implementation of an incident learning system in radiation oncology department

AimThe aim of this study was to analyze critical success factors (CSFs) for implementation of an incident learning system (ILS) in a radiation oncology department (ROD) and evaluate the perception of the staff members along this process.BackgroundImplementing an ILS is a way to leverage learning from incidents and is a tool for improving patient safety, consisting of a cycle of reporting and analyzing events as well as taking preventive actions. ILS implementation is challenging, requiring specific resources and cultural changes.Materials and methodsAn ILS was designed and implemented based on the CSF identified in the literature review. Before starting the ILS implementation, a structured survey was applied to assess dimensions of patient safety culture. After the period of implementation (7 months), the survey was applied again and compared with the initial assessment, and interviews were performed with staff members to evaluate the overall satisfaction with ILS and CSFs.ResultsStatistically significant improvements were observed in 5 dimensions (12 totals) of the safety culture survey, considering time points before and after the ILS implementation. According to interviewees, “Facilitating committee”, “Efficient data collection”, “Focus on improvement”, “Just culture” and “Feedback to users” were the most relevant CSFs.ConclusionsThe ILS designed and implemented at ROD was perceived as an important tool to support quality and safety initiatives, promoting the improvement in safety culture. The ILS implementation critical success factors were identified and have shown good agreement between the results of the literature and the users' practical perception.     

New perspectives in radiation oncology: Young radiation oncologist point of view and challenges

AimTo assess the role of the young radiation oncologist in the context of important recent advancements in the field of radiation oncology, and to explore new perspectives and competencies of the young radiation oncologist.BackgroundRadiation oncology is a field that has rapidly advanced over the last century. It holds a rich tradition of clinical care and evidence-based practice, and more recently has advanced with revolutionary innovations in technology and computer science, as well as pharmacology and molecular biology.Materials and methodsSeveral young radiation oncologists from different countries evaluated the current status and future directions of radiation oncology.ResultsFor young radiation oncologists, it is important to reflect on the current practice and future directions of the specialty as it relates to the role of the radiation oncologist in the comprehensive management of cancer patients. Radiation oncologists are responsible for the radiation treatment provided to patients and its subsequent impact on patients’ quality of life. Young radiation oncologists must proactively master new clinical, biological and technical information, as well as lead radiation oncology teams consisting of physicists, dosimetrists, nurses and technicians.ConclusionsThe role of the young radiation oncologist in the field of oncology should be proactive in developing new competencies. Above all, it is important to remember that we are dealing with the family members and loved ones of many individuals during the most difficult part of their lives.     

Impact of COVID-19 on the performance of a radiation oncology department at a major comprehensive cancer centre in Poland during the first ten weeks of the epidemic

The outbreak of SARS-CoV-2 coronavirus rapidly altered radiotherapy service delivery around the world.AimThe main objective of this study was to assess the impact of precautionary measures implemented in response to the COVID-19 pandemic on the performance of a radiation oncology departments and on mitigation the risk of COVID-19 contagion between and among patients and staff.MethodsThe study period was from March 15 until May 22, 2020. We evaluated total number of patients irradiated and those who initiated treatments, taking into account tumours localisations. We assessed the relationship of potential risk of contagion with patients’ domiciles locations in regions with high number of COVID19 case.Results and conclusionsThe number of patients treated with radiotherapy during the study period decreased due to precautionary measures. After five weeks, the number of radiotherapy treatments began to increase. Just over half of the radiotherapy patients (53.5%) treated at the GPCC reside in the city of Poznan or in one of the ten surrounding counties where COVID19 incidence was low and reached at the end of the study period cumulative number of cases n = 204. The precautionary measures were effective qRT-PCR tests were performed in 1545 individuals (patients and hospital staff) revealing four staff members and none patient with a positive PCR result. Immunoglobulin testing was performed in 1132 individuals (patients and hospital staff). A total of 63 individuals were positive for antibodies.     

Analysis of pre-residency research productivity,dual degree status,and gender distribution of underrepresented minorities among a current United States radiation oncology junior resident class

BackgroundAmong the most competitive medical subspecialties, representation of underrepresented minorities (African–American race and/or Hispanic ethnicity) among resident trainees has historically been low compared to their United States Census general population representation. Research productivity and dual degree status may impact residency applicant competitiveness. To date, such an analysis has yet to be performed in Radiation Oncology.MethodsA list of radiation oncology residents from the graduating class of 2022 was obtained through internet searches. Demographics included were gender and dual degree status. Research productivity was calculated using the number of pre-residency peer-reviewed publications (PRP). Fisher's exact test was used for statistical analysis.ResultsOf the 179 residents evaluated from the 2022 class, eleven (6.1%) were underrepresented minorities. Compared to the remainder of the class, underrepresented minorities had a lower proportion of men (63.6% versus 69.3%), a higher proportion of dual degrees (45.5% versus 28.6%), and a lower proportion of MD-PhD degrees (9.1% versus 17.2%). Underrepresented minorities had a higher proportion of residents with at least two PRP (72.7% versus 57.1%) and a lower proportion of residents with no PRP (18.2% versus 24.4%). None of these differences reached statistical significance (p > 0.05).ConclusionUnderrepresented minorities were comparable to the remainder of their Radiation Oncology resident class regarding gender distribution, dual degrees status, and likelihood of having at least two peer-reviewed publications cited in PubMed during the calendar year of residency application. Further studies will be needed to determine how these findings translate into future scholarly activity and post-graduate career choice.     

海岛生态系统服务价值评估及其时空变化——以浙江舟山金塘岛为例

生态系统服务价值研究是目前生态学研究的热点之一,海岛生态系统的特殊性令其更易受人类活动和环境变化的影响。文章在海岛生态系统服务价值当量修订的基础上,对典型海岛金塘岛1986—2014年的生态系统服务价值进行评估,分析了金塘岛近30年来生态系统服务价值的时空动态变化。结果表明:城镇生态系统面积持续增加,其他生态系统类型面积不同程度减少,减少的生态系统类型大多数转化为城镇。1986—2014年金塘岛的生态系统服务总价值呈下降趋势,共减少了1.08亿元,减少了30.23%,其中湿地与森林的生态系统服务价值量减少最多,城镇的价值变化率最大。空间上表现为价值极低区域沿着人类活动方向呈现急剧扩大趋势。生态系统提供的产品与服务在数量和质量上逐步下降,不利于海岛的可持续发展。该研究为海岛地区生态系统服务价值当量修订提供参考,同时对转变海岛经济发展方式,促进海岛可持续发展提供基础信息与决策依据。     

A Bayesian hierarchical non-linear regression model in receiver operating characteristic analysis of clustered continuous diagnostic data

Receiver operating characteristic (ROC) analysis is a useful evaluative method of diagnostic accuracy. A Bayesian hierarchical nonlinear regression model for ROC analysis was developed. A validation analysis of diagnostic accuracy was conducted using prospective multi-center clinical trial prostate cancer biopsy data collected from three participating centers. The gold standard was based on radical prostatectomy to determine local and advanced disease. To evaluate the diagnostic performance of PSA level at fixed levels of Gleason score, a normality transformation was applied to the outcome data. A hierarchical regression analysis incorporating the effects of cluster (clinical center) and cancer risk (low, intermediate, and high) was performed, and the area under the ROC curve (AUC) was estimated.     

1980—2018年海南岛土地利用与生态系统服务价值时空变化

以海南岛为研究区,利用1980—2018年5期土地利用数据,借助ArcGIS技术,综合运用价值当量因子法、生态系统服务变化指数(Ecological Services Change Index,ESCI)、空间统计分析等方法,探究了海南岛土地利用与生态系统服务价值(Ecosystem Services Values,ESV)的时空变化特征。结果表明:(1)林地是海南岛自然生态系统的主体,占62%以上,林地面积先升高后降低;建设用地增加迅猛,特别是在2010年以后,增长率高达122.46%,其次水域增长率为20.94%。土地利用主要呈现出草地转为林地,耕地、林地转为建设用地或水域的变化特征。(2)1980—2018年海南岛ESV总体表现为先增加后降低的变化趋势,净增加51.59亿元,增长率为2.56%。其中林地ESV占比最高,达70%以上;单项ESV以水文调节、气候调节为主,两者占总ESV的50%以上。(3)在空间分布上,海南岛ESV存在着明显的中部高、四周低的空间分异特征,在时间序列上高值区进一步萎缩、低值区逐渐扩展。(4)1980—2018年海南岛5个时期的ESV及其变化在空间分布上...     

基于文献计量的海洋生态系统服务研究热点与趋势分析

海洋为人类提供了自然资源和生存环境两方面的基础服务,研究海洋生态系统服务对提升海洋资本在推进实现联合国可持续发展目标(SDGs)中的作用具有重要意义。运用文献计量方法,以WEB OF SCIENCE数据库及CNKI数据库为数据源,检索国内外海洋生态系统服务相关文献,运用Bibexcel、Ucient和Netdraw等软件分别得到高频关键词、关键词共现网络可视图,并通过SPSS进行聚类分析。分析结果表明:①国内外发文量均成上升趋势,国外起始于1992年,与国内相比起始时间较早,增长幅度较大;②从关键词频次上看,国外多偏重于对气候变化和生物多样性与生态系统服务权衡与协同关系等的研究,国内则多偏重于生态系统服务价值的研究;③国外研究的热点为ecosystem services,climate change,biodiversity,fisheries,marine protected areas等,国内研究的热点为"评估"、"海洋生态补偿"、"价值"等;④根据聚类分析,国外研究方向一是侧重于海洋开发利用过程中的生态保护问题,二是气候变化对生态系统服务功能的影响,研究单元以各类生态系统为主,国...     

MRI in medical practice and its future use in radiation oncology. Resume of XXV GOCO Congress (Montpellier) 2017

This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics). After that, in the context of the present and future uses of MRI in radiation oncology, MRI guided radiotherapy was explained, as a method that allows an increased precision in image guided treatments. This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics).     

海南岛东北部土地利用与生态系统服务价值空间自相关格局分析

土地利用/覆被变化是全球环境变化的重要原因,对生态系统服务价值空间分布格局有直接影响。以海南岛东北部为研究对象,基于遥感影像数据,应用空间自相关理论定量探讨了土地利用与生态系统服务价值的空间自相关格局和分布特征,并运用双变量空间自相关分析两者之间的空间响应规律。结果表明:2016年海南岛东北部生态系统服务功能总价值为132.09亿元,其中林地构成生态系统服务功能价值的主体,而湿地的单位生态系统服务价值最高。土地利用类型具有显著的空间自相关性(P0.05),不同土地利用类型所表现的空间聚集或异常的区域及范围明显不同,以建设用地和林地的空间聚集性最强。研究区生态系统服务价值在空间上呈显著的正相关性(P0.05),高值区明显聚集于海岸带、东寨港和清澜港红树林一带,低值区集中在海口城区、文昌北部农耕区域;土地利用程度与生态系统服务价值呈空间负相关关系(P0.05),且具有明显的空间溢出效应。根据研究结论建议继续实施生态修复与保护政策,优化土地利用结构,提升生态核心的服务价值,实现区域可持续发展和维护生态安全。     

湖泊生态服务受益者分析及生态生产函数构建

生态系统服务管理作为生态系统管理的优化方式,是生态学研究的前沿方向。湖泊生态系统服务管理是指综合利用生态学、经济学、社会学和管理学等学科知识,对影响湖泊生态系统结构、过程、功能的关键因子进行调控,提高湖泊生态系统服务供给水平和供给能力的过程。近年来国内外学者针对湖泊生态系统服务内涵、分类、经济价值评估等方面开展了大量研究,极大地促进了湖泊生态系统服务从认知走向管理实践。然而,现有研究在开展湖泊生态系统服务价值评估时多忽略生态系统服务受益者和生态系统特征对生态系统服务的边际影响分析,无法揭示生态系统服务空间流动和转移特征及生态系统服务时空权衡关系,制约了生态系统服务研究与管理决策和政策设计结合。在综述湖泊生态系统服务定量评估方法的基础上,认为通过生态系统服务受益者分析确定湖泊生态系统最终服务,并通过构建生态生产函数确定湖泊生态系统服务权衡关系及湖泊生态系统特征对生态系统最终服务的边际影响,是生态系统服务走向管理实践和政策设计的科学依据,可以确保生态、社会、经济可持续发展。     

禁牧政策对宁夏盐池县农业生态系统服务影响的能值分析

农牧交错区农业可持续发展问题一直是我国区域农业研究的重要课题,以典型北方农牧交错区宁夏盐池县为例,利用农业生态系统能值分析框架,评估盐池县1991—2016年农业生态系统正反服务,揭示禁牧政策对农业可持续发展的影响。研究结果表明:(1) 1991—2016年盐池县农业投入能值和农业生态系统正反服务能值一直处于增长的趋势,禁牧政策实施以后增长速度高于禁牧之前,其中农业投入能值的增加主要是由于经济反馈能值投入的增加。(2)根据Pearson相关性分析,盐池县农业生态系统服务和反服务在0.01水平(双侧)呈显著的强正相关,农业生态系统服务和反服务具有相同的变化趋势。(3)生态环境的改善、经济反馈能值和农业灌溉面积的增加,可以增强北方农牧交错区农业抵御气候波动的能力。(4)盐池县农业可持续性高于全国和典型农区的平均水平,禁牧政策实施之前盐池县农业可持续性表现出稳定的下降趋势,而禁牧政策实施以后其可持续性表现为上升的趋势,禁牧政策的实施已初步实现农业生产的生态经济效益。     

成渝经济区土地利用与生态服务价值动态分析

成渝经济区是长江上游的生态屏障,其生态环境脆弱,维持和提高该区域的生态系统服务功能非常重要。基于2000和2007年遥感影像数据,利用GIS和RS工具定量分析了成渝经济区2000—2007年土地利用的时空变化特征,并运用改进的生态服务价值系数,评价了土地生态系统服务功能的动态变化。结果表明:研究期间区域内建设用地以5.3%的年增长率增加,增加面积1044.5km2;林地面积增加最大(2908.7km2),年变化率为0.5%;耕地、草地,水体和未利用地分别以-0.3%、-2.0%、-0.7%和-2.9%年变化率减少,其中耕地减少面积最大,为2388.9km2;2000—2007年土地生态系统服务功能有所上升,总价值由3188.4亿元增加到3211.5亿元;林地转入以及耕地和草地转出是导致总价值增加的主要原因,生态系统服务功能降低主要是由于林地转出所致。为维持区域生态系统服务功能,应加强对林地和湿地等生态系统服务价值高的土地类型的保护。     

人类基因组上CpG岛的定位和系统分析

为了研究CpG岛产生和消失机制以及位于基因启动子区域外的CpG岛保守性等问题,我们通过序列比对和进化保守性分析等方法,分析在人类和小鼠中保守的基因上的CpG岛。结果显示已有保守序列的突变以及序列插入删除是CpG岛产生和消失的主要原因,进一步分析发现52%的在小鼠基因组上保守序列完全缺失的CpG岛位于两个转座子之间,提示转座子所介导的序列插入是CpG岛形成和消失的重要原因。人类基因组上在启动子区域外的CpG岛中约有79%为新产生的CpG岛,显著高于启动子区域内新产生的CpG岛比例(41%)。GO分析表明与这些CpG岛相关的部分基因与神经系统发育显著相关,提示新产生的CpG岛参与神经发育过程。     

Comparative study of DNA damage and repair in head and neck cancer after radiation treatment

We compared DNA damage and the efficacy of its repair after genotoxic treatment with γ-radiation of lymphocytes and tissue cells isolated from patients with squamous cell carcinoma of head and neck (HNSCC) and healthy donors. Thirty-seven subjects with HNSCC and 35 healthy donors were enrolled in the study. The extent of DNA damage including oxidative lesions and efficiency of the repair were examined by alkaline comet assay. HNSCC cancer cells were more sensitive to genotoxic treatment and displayed impaired DNA repair. In particular, lesions caused by γ-radiation were repaired less effectively in metastasis of HNSCC than in healthy controls. The differences in radiation sensitivity of cancer and control cells suggested that DNA repair might be critical for HNSCC treatment. We conclude that γ-radiation might be considered as an effective therapeutic strategy for head and neck cancers, including patients in advanced stage of the disease with clear evidence of metastasis.     

Enhancing the conservation status and resilience of a narrowly distributed forest: A challenge to effectively support ecosystem services in practice

The conservation and sustainable management of forests has become an important issue, especially in ecosystems where keystone species form unique and marginal forest habitats with narrow distribution. With increasing pressures and threats to nature, the establishment of Protected Areas has been recognized as a major tool for maintaining well-functioning forest ecosystems and their associated ecosystem services (ES). This study aims at assessing the changes in the status of a narrowly distributed Mediterranean forest through the perspective of land cover dynamics and the ES framework. Using the priority habitat of Cedrus brevifolia forest as a case study, the distribution of land use and land cover (LULC) was mapped and simulated, together with the supply of multiple ES before and after the implementation of conservation measures. The results prior applying the management actions revealed a general pattern of forest densification that did not act fully in favor of C. brevifolia due to competitions among forest species. From an ES viewpoint, forest densification led to landscape homogenization affecting important ES such as the increase in the supply of regulating services, and the decrease in the ability to support nursery populations and habitats. By contrast, the future simulation of LULC integrated with afforestation and thinning measures showed an expected increase in both high-density vegetation and cedar trees, benefiting multiple ES. The current findings highlight the importance of sustainable forest management in enhancing the co-occurrence of several ES and supporting the overall multi-functionality of ecosystems. The holistic approach presented in this study can offer new insights into the relation between ES and natural ecosystem and/or habitats’ management while avoiding potential negative impacts on human well-being and ecosystem resilience.     

基于SolVES模型的关中-天水经济区生态系统文化服务评估

随着人类对于生态系统服务的需求持续增加,生态系统服务的评估逐渐成为研究热点。其中文化服务因其自身的无形性常在研究中被忽视且难以衡量。选取关中-天水经济区为研究区域,应用Sol VES模型并生成5种价值指数地图和价值总和地图来评估该区域生态系统的文化服务。结果表明:审美价值在秦岭山脉和城市公园等区域较高;娱乐价值在娱乐机会较多、交通便利的城市和秦岭北麓区域更高;文化与历史价值集中在历史文化底蕴深厚的城市地区;精神价值在与城市距离较近、有山川分布的森林公园更高。Sol VES模型在大范围区域的应用取得了较好的效果同时为政府进行生态建设和规划提供了科学依据。     

北京市景观格局演变及其对多种生态系统服务的影响

景观格局是人与自然共同作用的结果,深刻影响着区域的生态系统服务及可持续发展。以高度城市化地区——北京市为案例,选取了粮食生产、水质净化、空气净化、气体调节、生境质量以及休闲娱乐6项重要生态系统服务,采用InVEST （Integrated Valuation of Ecosystem Services and Tradeoffs）、ROS （Recreation Opportunity Spectrum）等模型定量评估了1980-2018年生态系统服务时空分布。通过对北京市景观组成与景观配置指数进行定量分析,进一步探索了景观格局演变对生态系统服务的影响。结果表明：（1）北京市1980-2018年建设用地扩张了120%,建设用地扩张是耕地面积减少的主要原因。景观格局总体上趋于破碎化,斑块形状复杂化,斑块异质性增加;（2）时间上,北京市1980-2018年粮食生产、水质净化、气体调节、生境质量、休闲娱乐5项生态系统服务均呈现下降趋势;空间上,粮食生产呈现东南部较高,西北部较低的分布特征,其余生态系统服务均呈现西北部较高,东南部较低,市中心最低的分布特征;（3）景观水平上,林地、建设用地等景观组成变化对生态系统服务影响最为显著。破碎化指数、多样性指数等景观配置指数对生态系统服务影响最为显著;类型水平上,平均斑块面积、斑块聚集度对生态系统服务影响相对最为显著。总体来讲,通过分析景观格局演变如何影响生态系统服务,为如何通过设计和优化景观格局来提升生态系统服务提供了定量依据,从而为促进区域的景观可持续规划提供理论依据和案例参考。