Three-dimensional recording of the human face with a 3D laser scanner.

Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces.     

Methods of Measuring Community Characteristics

There is increasing interest in the influence of community characteristics on child development and family functioning. In order to address questions on community influence, it is important to be aware of the measures available and their strengths and limitations. Useful strategies have been developed within a number of disciplines, including sociology, social and community psychology, and criminology. Methods include summarising information from existing administrative databases and census data, conducting observations, and using survey instruments with residents. The most commonly used methods are reviewed and their psychometric properties described .     

Education in family and community health: the challenge faced by a new medical school

This paper describes the efforts of the Department of Family and Community Health at Sultan Qaboos University in providing opportunities for the development of 'hands-on' problem-solving skills appropriate for Oman. The curriculum of the Department is discussed, highlighting the unusual emphasis of this discipline in both the preclinical and clinical curriculum of the College of Medicine. The importance of continuous assessment and supervision of students is discussed. Course-work in the preclinical curriculum of the Department is kept to a minimum. Field-work forms an important part of preclinical training, where application and problem-based learning are emphasized. During the clinical years the students are exposed to an integrated series of lectures and practicals covering core knowledge in clinical medicine. Practical clinical training, over a total period of 15 weeks, takes place at a variety of sites where common problems in primary health care in Oman are handled by students under supervision.     

Electrical impedance scanning in breast tumor imaging: correlation with the growth pattern of lesion

Background This study researched the electric impedance properties of breast tissue and demonstrated the differentcharacteristic of electrical impedance scanning (EIS) images.Methods The impedance character of 40 malignant tumors, 34 benign tumors and some normal breast tissue from 69patients undergoing breast surgery was examined by EIS in vivo measurement and mammography screening, with aseries of frequencies set between 100 Hz-100 kHz in the ex vivo spectroscopy measurement.Results Of the 39 patients with 40 malignant tumors, 24 showed bright spots, 11 showed dark areas in EIS and 5showed no specific image. Of the 30 patients with 34 benign tumors there were almost no specific abnormality shown inthe EIS results. Primary ex vivo spectroscopy experiments showed that the resistivity of various breast tissue take thefollowing pattern: adipose tissue＞cancerous tissue＞mammary gland and benign tumor tissue.Conclusions There are significant differences in the electrical impedance properties between cancerous tissue andhealthy tissue. The impedivity of benign tumor is lower, and is at the same level with that of the mammary glandulartissue. The distinct growth pattern of breast lesions determined the different electrical impedance characteristics in theEIS results.     

Limitations of a thermal camera in measuring surface temperature of laser-irradiated tissues

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3-5 microns thermal camera and two 8-12 microns cameras in detecting the maximum temperatures of small targets. The size of the targets was within the range of laser spot diameters which are used for vessel welding, angioplasty, and dermatology. The response to a sharp thermal edge was measured and analyzed for the three cameras, which had a scanning rate of 30 frames per second. The response of the 3-5 microns camera to reference black body targets of different sizes was also studied. It was found that the detector system required an average of 2.44 microseconds to reach 90% of maximum step response for the 8-12 microns system and 5.85 microseconds for the 3-5 microns system. With a 3 x telescope and a 9.5 inch focal distance close-up lens, the 3-5 microns camera underestimated the temperature of targets smaller than 2.0 mm because of its slow detector response. Although the 8-12 microns camera provides more accurate measurements due to its faster detector response, it still underestimates the temperature of targets smaller than 900 microns, when similar magnification and focal distance are used. Methods to compensate for the inaccuracies are discussed, including empirical correction factors and the inverse filtering technique.     

乳腺钼靶片计算机光密度测定的临床应用研究

目的：利用计算机对乳腺钼靶片上病灶中心及病灶周围影像光密度的测定，来探索良、恶性乳腺病变之间以及各种病变病灶中心与病灶周围影像的密度差异：探讨病理基础和临床意义。材料和方法：随机选取１００例临床可扪及乳腺＂肿块＂的女性病人，进行乳腺钼靶Ｘ线检查，将检出病变的１０２张钼靶片进行计算机处理后，对病灶中心及病灶周围组织影像的光密度进行测定。所有病例除炎性病变外均取得病理结果。结果：１．良性病变的病灶中心密度与病灶周围密度无显著差异（Ｐ＞０．５），良性肿块（指纤维腺瘤和囊肿）的病灶中心与病灶周围密度间仅提示一种可能存在显著差异的趋势（０．１＞Ｐ＞０．０５）；２．乳腺癌病灶中心与病灶周围密度之间存在非常显著的差异（Ｐ＜０．００１）；３．良、恶性肿瘤病灶中心密度之间存在较显著差异（Ｐ＜０．０５）。结论：本研究的结果有助于乳腺良、恶性病变的鉴别诊断和提高早期乳腺癌的检出率。     

超声弹性成像技术联合血清学标志物预测2型糖尿病的应用价值

<正>多项研究表明,非酒精性脂肪性肝病患者(NAFLD)发生2型糖尿病(type 2 diabetes mellitus,T2DM)的风险是正常人的5倍^[1-3]。在T2DM患者中,NAFLD的患病率可高达70%^[4]。肝脏瞬时弹性成像技术(tran-sient elastography,TE)是近年来新兴的超声无创检查方法,主要基于超声信号在肝组织中传播受肝细胞中脂滴的影响而出现显著衰减的原理来评估肝脏脂肪性病变,     

电阻应变式传感器在下肢牵引手术中的应用

目的 研究电阻应变式传感器（RSS）在不同下肢骨折类型手术中的应用。方法 选择2020年10月—2022年8月中国科学技术大学附属第一医院收治的外伤性下肢骨折患者99例,按照骨折类型分为股骨粗隆间骨折组79例、股骨干骨折组15例、股骨颈骨折组5例。患者均在牵引床上行闭合复位内固定术,使用RSS测量3组不同骨折类型手术中的初始牵引力、牵引时长、松解牵引力。记录手术时间、术中出血量,术后评分及3组不同骨折类型手术前后血色素变化及输血情况;比较使用不同内固定方式（长髓内钉、短髓内钉、空心钉）的术中牵引力和手术出血量、手术时间;比较长髓内钉固定患者和短髓内钉固定患者时下肢旋转角度。结果 3组不同骨折类型初始牵引力、牵引时长、松解牵引力、手术时长、术中出血量、术后评分比较,差异均有统计学意义（P <0.05）。3组不同骨折类型术前、术后血红蛋白、红细胞压积比较,差异均有统计学意义（P <0.05）。3组术中输血情况比较,差异有统计学意义（P <0.05）,术后输血情况比较,差异无统计学意义（P>0.05）。使用不同内固定方式的患者牵引总时长、年龄、术中出血量、手术时间比较...     

Measured attenuation correction methods

Accurate attenuation correction is a prerequisite for the determination of exact local radioactivity concentrations in positron emission tomography. Attenuation correction factors range from 4–5 in brain studies to 50–100 in whole body measurements. This report gives an overview of the different methods of determining the attenuation correction factors by transmission measurements using an external positron emitting source. The long-lived generator nuclide⁶⁸Ge/⁶⁸Ga is commonly used for this purpose. The additional patient dose from the transmission source is usually a small fraction of the dose due to the subsequent emission measurement. Ring-shaped transmission sources as well as rotating point or line sources are employed in modern positron tomographs. By masking a rotating line or point source, random and scattered events in the transmission scans can be effectively suppressed. The problems of measured attenuation correction are discussed: transmission/emission mismatch, random and scattered event contamination, counting statistics, transmission/emission scatter compensation, transmission scan after administration of activity to the patient. By using a double masking technique simultaneous emission and transmission scans become feasible.This article was presented at the 1st EEC workshop on accuracy determination in PET, January 19–20th. 1989 Pisa, Italy (COMAC-BME Concerted Project Characterization and Standardization of PET Instrumentation)     

Haemodynamic effects of atropine during halothane or isoflurane anaesthesia in infants and small children

In this study, two-dimensional and pulsed Doppler echocardiography were used to measure cardiovascular changes before and after IV atropine in 31 infants and small children during halothane (n = 15) or isoflurane (n = 16) anaesthesia. Prior to induction of anaesthesia heart rate (HR), mean blood pressure (MBP), and two0dimensional echocardiographic dimensions of the left ventricle and pulmonary artery bloodflow velocity were measured by pulsed Doppler echocardiography. Cardiovascular measurements were repeated while anaesthesia was maintained at 1.5 MAC halothane (n = 15) or isoflurane (n = 16). Atropine 0.02 mg·kg⁻¹ IV was then administered and two minutes later, a third set of cardiovascular data was obtained. Heart rate decreased during halothane anaesthesia but did not change significantly during isoflurane anaesthesia. Mean blood pressure, cardiac output (CO) and stroke volume (SV) decreased similarly during 1.5 MAC halothane or isoflurane anaesthesia. Ejection fraction (EF) decreased and left ventricular end-diastolic volume (LVEDV) increased significantly in bothgroups, but decreases in EF (32 ± 5 percentvs18 ± 5 per cent) and increases in LVEDV (18 ± 7 per cent vs7 ± 5 per cent) were significantly greater during halothane than during isoflurane anaesthesia. Following atropine, HR increased more in the patients maintained with halothane (31 ± 6 per cent), than during isoflurane anaesthesia (18 ± 5 per cent). Atropine increased CO in both groups of patients, but SV and EF remained unchanged. When compared with awake values, HR increased similarly and significantly (18 ± 4 per cent) following atropine in both groups, and CO returned to control levels. Halothane decreased EF and increased LVEDV more than isoflurane at 1.5 MAC end— expired anaesthetic levels. Atropine did not diminish the myocardial depression produced by halothane or isoflurane. The increase in CO following atropine during halothane and isoflurane anaesthesia in infants and small children is the result of increases in HR alone. Nous avons utilisé un appareil à échocardiographie bi-dimensionnelle couplé à un Doppler pulsé chez des bébés et de jeunes enfants pour évaluer l’impact hémodynamique de l’halothane (n = 15) et de l’isoflurane (n = 16) et la modification possible de ces effets par l’atropine. Nous avons mesure la frequence cardiaque (FC), la pression artérielle moyenne (PAM), la dimension de la cavité ventriculaire gauche (par écho bi-dimensionnelle) et la vélocité du flot sanguin pulmonaire (par Doppler) et ce, en trois occasions soit avant l’induction, après l’instauration de 1.5 MAC d’halothane ou d’isoflurane et finalement, deux minutes après l’injection IV de 0.02 mg·kg⁻¹ d’atropine. On ne nota une baisse de la frequence cardiaque qu’avec l’halothane tandis que la PAM, le débit cardiaque (DC) et le volume d’éjection (VE) diminuaient autant avec l’un ou l’autre anesthésique. La diminution de la fraction d’éjection (FE) et l’augmentation du volume télédiastolique du ventricule gauche (VTDVG) significatives pour les deux groupes, étaienl plus marqué avec l’halothane qu’avec l’isoflurane: FE 32 ± 5 pour cent vs18 ±5 pour cent; VTDVG 18 ± 7 pour cent vs 7 ± 5 pour cent. Avec l’atropine, la FC monta plus dans le groupe halothane (31 ± 6 pour cent) que dans le groupe isoflurane (18 ± 5 pour cent), le DC augmentant dans les deux groupes, alors que le VE et la FE demeuraient inchangés. Comparée aux mesures pré-induction, l’atropine amenait une hausse significative de la FC, semblable dans les deux groupes (18 ± 4 pour cent) et restaurait le DC. Donc, chez les bebes et les jeunes enfants, a 1.5 MAC, l’halothane diminue la FE et augmente le VTDVG plus que ne le fait l’isoflurane. L’atropine ne modifie pas la depression myocardique et elle ne restaure le DC que par une hausse de la FC.

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Supported by PHS Grant No. 8507300 from the College of Medicine, University of Iowa Hospital, Iowa City, IA.