Magnetic resonance imaging (MRI) contrast agents for tumor diagnosis

10.1260/2040-2295.4.1.23Journal of Healthcare Engineering4123-4

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Étude d'un écoulement mixte air-eau vertical descendant : régimes, évolution de la concentration

The authors consider the emulsion formed by a jet impinging upon a free water surface in an upright cylindrical pipe. Starting out from set initial data, they observe three main types of two-phase flow : (1) flow without air entrainment (2) practically stable air entrainment and (3) air entrainment with unstable pockets. This paper comprises three basic parts, one for each stage to be covered in order to gain an overall view of the question : (i) General equations based on simplifying assumptions but nevertheless closely agreeing with experimental data ; (ii) Air entrainment by the jet, expressed by empirical formulae at this stage ; (iii) The general 'mechanism' of the emulsion, which was first investigated experimentally by recording air-in-water concentration profiles by the gamma-ray method and comparing them with Wallis and Zuber-Findlay diagrams. The first of these is adequate for flow without air entrainment, and the second, which is based on non-uniform velocity and concentration distributions, enables the results of measurements to be interpreted in the entrained air case and a simple relationship to be put forward between mean concentration and the rates of air and water flow

Contribution à l’étude du drainage. Etude par analogies, du comportement d’un drain d’interception dans quelques cas particuliers

An analogy study of certain special cases of conditions in an interception drain as a contribution to general drainage research. Interception drain problems are highly complex and involve a large number of parameters, thus making mathematical analysis very difficult. Darcy’s formula is the basic equation used, by means of which analogies satisfying Laplace’s equation can be applied. A systematic drainage study has been undertaken in which electrical and viscous fluid analogies were applied. Two results are presented for a diagrammatic case involving a drain between two symmetrical feeder areas.Les problèmes de drains d'interception sont complexes et font intervenir, un nombre important de paramètres qui rendent l'analyse mathématique des phénomènes malaisée. ) L'équation de base est la formule de Darcy qui permet l'utilisation d'analogies satisfaisant à l'équation de Laplace. Une étude systématique du drainage a été entreprise à l'aide de l'analogie électrique et de l'analogie des fluides visqueux. Deux résultats sont présentés, dans le cas schématisé où le drain est situé entre deux zones d'alimentation symétriques.Curtet R., Ruby P. Contribution à l’étude du drainage. Etude par analogies, du comportement d’un drain d’interception dans quelques cas particuliers. In: L'hydraulique souterraine. Compte rendu des sixièmes journées de l'hydraulique, Nancy, 28-30 juin 1960. Tome 1, 1961

Sur la formation de bulles en aval d’un diaphragme aéré

On the formation of bubbles leaving an orifice exposed to air. The authors give some experimental results on the flow of water from an orifice in a vertical duct containing a volume of air. In particular, an account is given of the change in the free fall length of the jet and the length of the airwater foam as a function of the initial volume of air and the orifice diameter, also taking into consideration the pressure at the duct wall and the average concentration of the mixture.Les auteurs donnent quelques résultats expérimentaux sur l'écoulement en aval d'un diaphragme placé dans une conduite verticale, lorsque le jet d'eau issu du diaphragme se trouve en présence d'un volume d'air initialement enfermé dans la conduite. Ils présentent notamment l'évolution de la longueur de chute libre du jet et de la longueur d'émulsion air-eau en fonction du volume d'air initial et du diamètre de l'orifice, ainsi que la pression à la paroi de la conduite et la concentration spatiale moyenne du mélange.Curtet R., Djonin K. Sur la formation de bulles en aval d’un diaphragme aéré. In: Bulles et gouttes. La tension superficielle en hydraulique. Compte rendu des septièmes journées de l'hydraulique. Paris, 4, 5 et 6 juin 1962. Tome 2, 1963

TURBULENCE INSTATIONNAIRE DANS LES JETS PULSANTS OU BATTANTS

En forçant des perturbations de forte amplitude, pulsations ou battements sur des jets, on engendre des écoulements périodiques à turbulence instationnaire. La visualisation par bulles d'hydrogène met en évidence de grosses structures se propageant au sein de la zone turbulente. Des mesures utilisant l'anémométrie à fil chaud et une méthode d'échantillonnage périodique montrent qu'un important transfert d'énergie s'effectue de la fluctuation périodique à la turbulence pour les deux types de perturbations. Dans les jets puisants, l'évolution de la turbulence au cours de la phase révèle l'existence d'une bouffée concentrée dans le temps et d'activité très intense qui coïncide avec la crête du mouvement de base.Periodic flows with nonstationary turbulence are generated by forcing large pulsating or flapping perturbations on jets. Hydrogen bubble visualizations reveal large scale structures moving in the turbulent flow. Phase averaged hot wire anemometer measurements show that an important energy transfer from the periodic fluctuation to the turbulence takes place for both types of perturbations. The phase evolution of turbulence in pulsating jets shows the existence of a concentrated burst of intense activity riding on the crest of the basic motion

Discrepancy between antihypertensive effect and angiotensin converting enzyme inhibition by captopril

Captopril, an inhibitor of angiotensin converting enzyme, was administered twice daily to 13 hypertensive patients for a mean period of 9 weeks. Continuous blood pressure control in the ambulatory patients was established with a portable blood pressure recorder. Notwithstanding, in eight patients with normal renal function, plasma converting enzyme was found to resume normal activity before administration of the morning dose of captopril. Only in 5 patients with impaired renal function did some blockade of plasma converting enzyme persist for more than 12 hours. Measured plasma converting enzyme activity seemed to reflect total conversion of angiotensin I, including conversion in the pulmonary vascular bed, since changes in its activity were closely paralled by changes in plasma aldosterone levels. Bradykinin accumulation seems unlikely when converting enzyme and thus, presumably, kininase II has resumed normal activity. Captopril administration does not seem to alter plasma epinephrine or norepinephrine levels. Blood pressure reduction in the face of normal angiotensin converting enzyme activity is probably due to hyporesponsiveness of the arterioles to pressor hormones, which may be due to specific renin-related and/or nonspecific effects of captopril