基于机器学习的医学影像分析在药物研发和精准医疗方面的应用

MRI,PET,和CT等医学影像在新药研发和精准医疗中起着越来越重要的作用。影像技术可以被用来诊断疾病,评估药效,选择适应患者,或者确定用药剂量。 随着人工智能技术的发展,特别是机器学习以及深度学习技术在医学影像中的应用,使得我们可以用更短的时间,更少的放射剂量获取更高质量的影像。这些技术还可以帮助放射科医生缩短读片时间,提高诊断准确率。除此之外,机器学习技术还可以提高量化分析的可行性和精度,帮助建立影像与基因以及疾病的临床表现之间的关系。首先根据不同形态的医学影像,简单介绍他们在药物研发和精准医疗中的应用。并对机器学习在医学影像中的功能作一概括总结。最后讨论这个领域的挑战和机遇。     

Evaluation of PACS-induced organizational change

Filmless digital imaging with a PACS will affect health care institutions by changing the handling of clinically relevant information, altering needed staffing levels, and possibly affecting both the quality and cost of care. Economic evaluation of PACS compares the costs and/or benefits of PACS with those of all other relevant alternatives. Other evaluations may focus on narrower research questions. This paper discusses methodological considerations in economic evaluation, methods of time measurement, and the methods and results of several applied assessments of PACS effects on the medical imaging department or the hospital.     

Imaging the division process in living tissue culture cells

We detail some of the pitfalls encountered when following live cultured somatic cells by light microscopy during mitosis. Principle difficulties in this methodology arise from the necessity to compromise between maintaining the health of the cell while achieving the appropriate temporal and spatial resolutions required for the study. Although the quality of the data collected from fixed cells is restricted only by the quality of the imaging system and the optical properties of the specimen, the major limiting factor when viewing live cells is radiation damage induced during illumination. We discuss practical considerations for minimizing this damage, and for maintaining the general health of the cell, while it is being followed by multi-mode or multi-dimensional light microscopy.     

Historique de l’imagerie en médecine nucléaire

Nuclear medicine is one among the older medical imaging current modalities. Its story is closely tied to those of radioactivity (natural then artificial) and of related instrumentation. It took indeed many advantages from all progresses gained in domains as different as nuclear physics and nuclear chemistry, physics of radiation detectors, and electronics. Its recent and current developments continue to give it an important place in medical diagnosis.     

Mise en place d’une équipe d’experts en physique médicale au Luxembourg : organisation, résultats qualité et radioprotection en médecine nucléaire (2002–2011)

Implementations of the statutory UE requirements concerning ionizing radiation in the medical domain (96/29/Euratom, 13th May 1996; 97/43/Euratom, 30th June 1997) have changed quality control in medical imaging departments. In Luxembourg, the Ministry of Health and the “Union of Luxembourg Hospitals” have thus created a “Medical Physics Cell” (five Medical Physics experts). It is in charge of implementing a standardized program of Quality Assurance (QA) and radiation protection relative to patients as well as staffs, on a coordinated national basis, in all five in-hospital nuclear medicine departments of the country. The program distributes QA controls between three levels, various periodicities and degrees of expertise. It sensitizes staff and medical doctors by trainings and facilitates ISO accreditation. From 2002 to 2011, in all five in-hospital departments of nuclear medicine of a small country, image quality, radiation protection and reference values of each medical equipment were defined and implemented in a standard way. In 2011, the medical physics cell, the driving force leading to the institutionalization of the discipline within the nuclear medicine departments, is considered as a partner rather than as a control body by the teams in charge of the nuclear medicine departments.     

PACS辅助教学在医学影像学实习教学中的应用探讨

尝试应用影像存储及传输系统(Picture Archiving and Communication System,PACS),对我院临床本科生进行影像学实习教学。首先应用PACS建立电子影像学图片库,学生在PACS联网的计算机上学习教学内容,通过定期随堂测验、期末考试和课后问卷调查评估PACS辅助教学的教学效果,对PACS辅助教学在医学影像学实习教学中的应用价值进行探讨。与以往传统医学影像学实习教学方法相比,PACS辅助教学在医学影像学实习教学中具有激发学生学习主动性、提高学习效率和学生读片能力的优越性,显著提高教学效果和教学质量,对促进医学影像学教学改革具有重要意义。     

低剂量和常规剂量螺旋CT动态扫描对慢性阻塞性肺疾病患者辐射剂量、成像质量及满意度的影响

摘要 目的：探讨低剂量和常规剂量螺旋CT动态扫描对慢性阻塞性肺疾病（COPD）患者辐射剂量、成像质量及满意度的影响。方法：选取我院于2019年1月~2020年1月收治的初步诊断为COPD的患者88例。将患者采用单双号分组法分为低剂量组和常规组,各44例。低剂量组采用低剂量螺旋CT动态扫描,常规组采用常规剂量螺旋CT动态扫描。比较两组的辐射剂量、成像质量以及COPD的诊断结果。比较两组满意度评分。结果：低剂量组CT剂量加权指数（CTDIw）、剂量长度乘积（DLP）以及有效辐射剂量（ED）均明显低于常规组,差异有统计学意义（P<0.05）。常规组成像质量的优秀率明显高于低剂量组（P<0.05）,但两组成像质量的优良率对比无明显差异（P>0.05）。低剂量组灵敏度、特异度与常规组比较差异无统计学意义（P>0.05）。低剂量组患者满意度评分明显高于常规组（P<0.05）。结论：低剂量螺旋CT动态扫描对于COPD的诊断价值与常规剂量CT动态扫描相当,且可以保证成像质量,同时其能明显降低辐射剂量、提高COPD患者满意度,具有一定的临床应用价值。     

Cost effectiveness of magnetic resonance imaging in the neurosciences.

OBJECTIVES--To measure, in a service setting, the effect of magnetic resonance imaging on diagnosis, diagnostic certainty, and patient management in the neurosciences; to measure the cost per patient scanned; to estimate the marginal cost of imaging and compare this with its diagnostic impact; to measure changes in patients'' quality of life; and to record the diagnostic pathway leading to magnetic resonance imaging. DESIGN--Controlled observational study using questionnaires on diagnosis and patient management before and after imaging. Detailed costing study. Quality of life questionnaires at the time of imaging and six months later. Diagnostic pathways extracted from medical records for a representative sample. SETTING--Regional superconducting 1.5 T magnetic resonance service. SUBJECTS--782 consecutive neuroscience patients referred by consultants for magnetic resonance imaging during June 1988-9; diagnostic pathways recorded for 158 cases. MAIN OUTCOME MEASURES--Costs of magnetic resonance imaging and preliminary investigations; changes in planned management and resulting savings; changes in principal diagnosis and diagnostic certainty; changes in patients'' quality of life. RESULTS--Average cost of magnetic resonance imaging was estimated at 206.20/patient pounds (throughput 2250 patients/year, 1989-90 prices including contrast and upgrading). Before magnetic resonance imaging diagnostic procedures cost 164.40/patient pounds (including inpatient stays). Management changed after imaging in 208 (27%) cases; saving an estimated 80.90/patient pounds. Confidence in planned management increased in a further 226 (29%) referrals. Consultants'' principal diagnosis changed in 159 of 782 (20%) referrals; marginal cost per diagnostic change was 626 pounds. Confidence in diagnosis increased in 236 (30%) referrals. No improvement in patients'' quality of life at six month assessment. CONCLUSIONS--Any improvement in diagnosis with magnetic resonance imaging is achieved at a higher cost. Techniques for monitoring the cost effectiveness of this technology need to be developed.     

基于超声的多模式功能化对比剂研究进展

超声对比剂的使用使得超声诊断更加准确,扩大了超声成像的应用范围。但单一影像技术难以满足肿瘤等重大疾病临床诊断和治疗的需求。因此开发以超声对比剂为核心,具有多模式成像功能,或同时兼备肿瘤诊断和治疗功能的多模式功能化对比剂是目前的一大研究热点。多模式成像的结合可以实现优势互补,诊断和治疗功能的结合为使得肿瘤等重大疾病的解决提供了新理念和新希望,具有重要意义。本文就基于超声的多模式功能化对比剂进行综述。     

Magnetic resonance imaging: present and future applications

Magnetic resonance (MR) imaging has created considerable excitement in the medical community, largely because of its great potential to diagnose and characterize many different disease processes. However, it is becoming increasingly evident that, because MR imaging is similar to computed tomography (CT) scanning in identifying structural disorders and because it is more costly and difficult to use, this highly useful technique must be judged against CT before it can become an accepted investigative tool. At present MR imaging has demonstrated diagnostic superiority over CT in a limited number of important, mostly neurologic, disorders and is complementary to CT in the diagnosis of certain other disorders. For most of the remaining organ systems its usefulness is not clear, but the lack of ionizing radiation and MR''s ability to produce images in any tomographic plane may eventually prove to be advantageous. The potential of MR imaging to display in-vivo spectra, multinuclear images and blood-flow data makes it an exciting investigative technique. At present, however, MR imaging units should be installed only in medical centres equipped with the clinical and basic research facilities that are essential to evaluate the ultimate role of this technique in the care of patients.     

256层螺旋CT前瞻性心电门控冠状动脉成像的临床应用价值及其对比剂浓度研究

目的:探讨256层螺旋CT前瞻性心电门控冠状动脉成像的临床应用价值及不同浓度对比剂对其成像质量、碘用量以及有效辐射剂量的影响。方法:对120例疑似冠心病患者行256层螺旋CT成像扫描,将患者随机分为前瞻性心电门控组和回顾性心电门控组;出院前再将前瞻性心电门控组患者按数表法随机分为低浓度对比剂组、中浓度对比剂组和高浓度对比剂组。比较各组成像质量、碘用量、有效辐射剂量。结果:前瞻性心电门控组与回顾性心电门控组图像质量主观评分分布、可评价节段率、优良率、有效碘用量、信噪比(SNR)、载噪比(CNR)、主动脉CT值(CT主)、主动脉噪声值(SD主)比较无统计学差异(P0.05)。前瞻性心电门控组有效辐射剂量显著低于回顾性心电门控组(P0.05)。高浓度对比剂组可评价节段率、优良率、有效碘用量、SNR、CNR、CT主显著高于低浓度对比剂组和中浓度对比剂组(P0.05),中浓度对比剂组CNR显著高于低浓度对比剂组(P0.05)。结论:前瞻性心电门控技术用于冠心病诊断的图像质量与回顾性心电门控技术无明显差异,但是前瞻性心电门控技术辐射剂量更低。前瞻性心电门控使用低浓度对比剂可以获得满足临床诊断需要的图像质量,且碘用量更少。     

Radiation dose of digital radiography (DR) versus micro-dose x-ray (EOS) on patients with adolescent idiopathic scoliosis: 2016 SOSORT- IRSSD “John Sevastic Award” Winner in Imaging Research

Background

Patients with adolescent idiopathic scoliosis (AIS) frequently receive x-ray imaging at diagnosis and subsequent follow monitoring. The ionizing radiation exposure has accumulated through their development stage and the effect of radiation to this young vulnerable group of patients is uncertain. To achieve the ALARA (as low as reasonably achievable) concept of radiation dose in medical imaging, a slot-scanning x-ray technique by the EOS system has been adopted and the radiation dose using micro-dose protocol was compared with the standard digital radiography on patients with AIS.

Methods

Ninety-nine participants with AIS underwent micro-dose EOS and 33 underwent standard digital radiography (DR) for imaging of the whole spine. Entrance-skin dose was measured using thermoluminescent dosimeters (TLD) at three regions (i.e. dorsal sites at the level of sternal notch, nipple line, symphysis pubis). Effective dose and organ dose were calculated by simulation using PCXMC 2.0. Data from two x-ray systems were compared using independent-samples t-test and significance level at 0.05. All TLD measurements were conducted on PA projection only. Image quality was also assessed by two raters using Cobb angle measurement and a set of imaging parameters for optimization purposes.

Results

Entrance-skin dose from micro-dose EOS system was 5.9–27.0 times lower at various regions compared with standard DR. The calculated effective dose was 2.6?±?0.5 (μSv) and 67.5?±?23.3 (μSv) from micro-dose and standard DR, respectively. The reduction in the micro-dose was approximately 26 times. Organ doses at thyroid, lung and gonad regions were significantly lower in micro-dose (p?<?0.001). Data were further compared within the different gender groups. Females received significantly higher (p?<?0.001) organ dose at ovaries compared to the testes in males. Patients with AIS received approximately 16–34 times lesser organ dose from micro-dose x-ray as compared with the standard DR. There was no significant difference in overall rating of imaging quality between EOS and DR. Micro-dose protocol provided enough quality to perform consistent measurement on Cobb angle.

Conclusions

Entrance-skin dose, effective dose and organ dose were significantly reduced in micro-dose x-ray. The effective dose of a single micro-dose x-ray (2.6 μSv) was less than a day of background radiation. As AIS patients require periodic x-ray follow up for surveillance of curve progression, clinical use of micro-dose x-ray system is beneficial for these young patients to reduce the intake of ionizing radiation.

     

Modifying normal tissue damage postirradiation. Report of a workshop sponsored by the Radiation Research Program, National Cancer Institute, Bethesda, Maryland, September 6-8, 2000

Late effects that develop in normal tissues adjacent to the tumor site in the months to years after radiotherapy can reduce the quality of life of cancer survivors. They can be dose-limiting and debilitating or life-threatening. There is now evidence that some late effects may be preventable or partially reversible. A workshop, "Modifying Normal Tissue Damage Postirradiation", was sponsored by the Radiation Research Program of the National Cancer Institute to identify the current status of and research needs and opportunities in this area. Mechanistic, genetic and physiological studies of the development of late effects are needed and will provide a rational basis for development of treatments. Interdisciplinary teams will be needed to carry out this research, including pathologists, physiologists, geneticists, molecular biologists, experts in functional imaging, wound healing, burn injury, molecular biology, and medical oncology, in addition to radiation biologists, physicists and oncologists. The participants emphasized the need for developing and choosing appropriate models, and for radiation dose-response studies to determine whether interventions remain effective at the radiation doses used clinically. Both preclinical and clinical studies require long-term follow-up, and easier-to-use, more objective clinical scoring systems must be developed and standardized. New developments in biomedical imaging should provide useful tools in all these endeavors. The ultimate goals are to improve the quality of life and efficacy of treatment for cancer patients treated with radiotherapy.     

郑州市第五人民医院PACS医学影像系统设计

本文介绍了郑州市第五人民医院PACS医学影像系统,描述了系统的目标,构架,功能和特点,采用了功能化的模块设计。可满足后续设备联入系统,已应用于医院的医疗过程中,解决了医学图像的获取,显示,存储,传输和管理等问题。符合DICOM3.0国际信息交换标准,实现了数字化,网络化和无胶片化的现代化医学影像诊断与管理,显著提高了诊疗质量和工作效率,降低了医疗成本,增加了经济收入和社会效益,对其它医院实现数字化进程也具有一定的借鉴意义。     

Research at the European Synchrotron Radiation Facility medical beamline.

The application of synchrotron radiation in medical research has become a mature field of research at synchrotron facilities worldwide. In the relatively short time that synchrotrons have been available to the scientific community, their characteristic beams of UV and X-ray radiation have been applied to virtually all areas of medical science which use ionizing radiation. The ability to tune intense monochromatic beams over wide energy ranges differentiates these sources from standard clinical and research tools. At the European Synchrotron Radiation Facility (Grenoble, France), a major research facility is operational on an advanced wiggler radiation beamport, ID17. The beamport is designed to carry out a broad range of research ranging from cell radiation biology to in vivo human studies. Medical imaging programs at ID17 include transvenous coronary angiography, computed tomography, mammography and bronchography. In addition, a major research program on microbeam radiation therapy is progressing. This paper will present a very brief overview of the beamline and the imaging and therapy programs.     

Computer aided diagnosis of Coronary Artery Disease,Myocardial Infarction and carotid atherosclerosis using ultrasound images: A review

The diagnosis of Coronary Artery Disease (CAD), Myocardial Infarction (MI) and carotid atherosclerosis is of paramount importance, as these cardiovascular diseases may cause medical complications and large number of death. Ultrasound (US) is a widely used imaging modality, as it captures moving images and image features correlate well with results obtained from other imaging methods. Furthermore, US does not use ionizing radiation and it is economical when compared to other imaging modalities. However, reading US images takes time and the relationship between image and tissue composition is complex. Therefore, the diagnostic accuracy depends on both time taken to read the images and experience of the screening practitioner. Computer support tools can reduce the inter-operator variability with lower subject specific expertise, when appropriate processing methods are used. In the current review, we analysed automatic detection methods for the diagnosis of CAD, MI and carotid atherosclerosis based on thoracic and Intravascular Ultrasound (IVUS). We found that IVUS is more often used than thoracic US for CAD. But for MI and carotid atherosclerosis IVUS is still in the experimental stage. Furthermore, thoracic US is more often used than IVUS for computer aided diagnosis systems.     

Artificial intelligence in image reconstruction: The change is here

Innovations in CT have been impressive among imaging and medical technologies in both the hardware and software domain. The range and speed of CT scanning improved from the introduction of multidetector-row CT scanners with wide-array detectors and faster gantry rotation speeds. To tackle concerns over rising radiation doses from its increasing use and to improve image quality, CT reconstruction techniques evolved from filtered back projection to commercial release of iterative reconstruction techniques, and recently, of deep learning (DL)-based image reconstruction. These newer reconstruction techniques enable improved or retained image quality versus filtered back projection at lower radiation doses. DL can aid in image reconstruction with training data without total reliance on the physical model of the imaging process, unique artifacts of PCD-CT due to charge sharing, K-escape, fluorescence x-ray emission, and pulse pileups can be handled in the data-driven fashion. With sufficiently reconstructed images, a well-designed network can be trained to upgrade image quality over a practical/clinical threshold or define new/killer applications. Besides, the much smaller detector pixel for PCD-CT can lead to huge computational costs with traditional model-based iterative reconstruction methods whereas deep networks can be much faster with training and validation. In this review, we present techniques, applications, uses, and limitations of deep learning-based image reconstruction methods in CT.     

生物医学光学中NADH荧光检测技术的发展

NADH(还原型烟酰胺腺嘌呤二核苷酸)自1962年被发现至今已有五十多年了,在此期间,运用NADH及其相关技术进行医疗诊断与医学检测的方式不断发展,领域也不断扩大。从当前的研究成果来看,NADH因为其独有的性质在现代医学诊断与检测领域发挥了极大的作用,如实时、无损地监测脑部的活动;清晰、有效地识别不同种类的脑组织;抗细胞辐射损伤;抗辐射诱导的细胞凋亡;进行人体内的诸多平衡调节及人体生物钟调节等。本文将重点介绍在重要领域中的NADH研究和应用的突破。     

超声弹性成像技术在前列腺癌诊断中的应用

超声弹性成像技术是一项新兴的超声成像方法,可通过分析不同组织间机械组织差异区分组织软硬度,早期主要应用于乳腺、甲状腺结节的区分和定性。随着科技的进步和医疗水平的提高,目前弹性成像技术可在二维声像图的基础上,对感兴趣区域进行定性诊断和定量分析,已逐步应用于医学各领域相关研究和临床疾病的鉴别诊断。本文介绍了弹性成像的基本原理和目前弹性成像技术在医学领域中的相关应用,叙述了前列腺癌的发展趋势和目前常用的筛查、诊断方法,详细阐述了弹性成像技术在前列腺癌诊断中的应用方法和现状,分析总结了弹性成像技术在前列腺癌诊断中的应用价值。运用弹性成像技术无创、经济便捷、实时动态、可重复性好等优点,联合前列腺癌相关筛查、诊断检查,可有效帮助早期诊断前列腺癌,减少前列腺穿刺术的针数,提高前列腺癌的检出率。