摘要:

Localization of eloquent areas is of utmost importance in neurosurgical planning, especially in epilepsy surgery. Mass, destructive, or developmental lesions may distort brain anatomy. Functional MRI (fMRI) can localize eloquent areas despite these distortions and provide useful information for the planning of tailored resections. This paper deals with the major issues concerning the use of fMRI in epilepsy surgery, including its limitations. We present results derived from the clinical experience of the Epilepsy Surgery Center at Ribeira˜o Preto School of Medicine, where typical finger tapping and language fMRI paradigms were applied to 40 patients being considered for resective epilepsy surgery around eloquent cortex. Our results confirmed that although fMRI may not be used as a single tool for surgical planning, in conjunction with other methods it is useful in reducing the surgical time, it improves lesion resection, and prevents functional deficits. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811811

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Recent advances in electrophysiology of the gastrointestinal tract have emphasized the need for methods of noninvasive assessment of gastric and small intestinal electrical activity (GEA and IEA). While the cutaneous electrogastrogram (EGG) may reveal the frequency dynamics of gastric electrical activity, other parameters important for characterizing the propagating electrical activity are not available from EGG recordings. Recent studies on the electroenterogram (EENG) are promising, but low‐conductivity abdominal layers have complicated the identification of small intestinal electrical rhythms in cutaneous recordings. The magnetogastrogram (MGG) and magnetoenterogram (MENG) are able to characterize gastric and intestinal electrical activity noninvasively in terms of its frequency, power and characteristics of its propagation. Superconducting QUantum Interference Device (SQUID) magnetometers are used to detect the minute magnetic fields associated with electrical activity of the gastrointestinal syncytium formed by interstitial cells of Cajal and smooth muscle networks. Changes in GEA and IEA that occur in response to disease or abnormal conditions are reflected in MGG and MENG signals. Magnetic methods for assessing the electrical activity of the stomach and small bowel thus show great clinical promise. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811812

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Biomagnetic methods, such as magnetoencephalography (MEG), magnetocardiography (MCG), and biosusceptometry, are becoming widely recognized for their unique and important capabilities. However, the high cost and impracticality of low‐temperature superconductor quantum interference devices (SQUIDs) has limited the dissemination of these methods, especially in countries where the cost of liquid helium is high. Several new technologies have the potential to change this situation. One is high‐temperature superconductor (HTS) SQUID technology, which has been pursued since the discovery of HTS materials in 1986. Another is optical magnetometry, which has received much attention since the report last year of a major breakthrough. In this paper, I will review the principles of operation of current and candidate technologies and discuss their future prospects. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811813

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Radiation dosimetry is fundamental in Medical Physics, involving patients and phantom dosimetry. In both cases thermoluminescence dosimetry (TLD) is the most appropriate technique for measuring the absorbed dose. In this paper thermoluminescence phenomenon as well as the use of TLD in radiodiagnosis and radiotherapy for in vivo or in phantom measurements is discussed. Some results of measurements made in radiotherapy and radiodiagnosis using home made LiF:Mg,Cu,P+PTFE TLD are presented. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811814

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Any physiological or anatomical changes in a biological material will also change its electrical properties. Hence, bioimpedance measurements can be used for diagnosing or classification of tissue. Applications are numerous within medicine, biology, cosmetics, food industry, sports, etc, and different basic approaches for the development of bioimpedance techniques are discussed in this paper. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811815

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

As medical facilities across the United States continue to convert their radiology operations from film‐based to digital environments, partially accomplished and failed endeavors are frequent because of the lack of competent and knowledgeable leadership. The diagnostic medical physicist is, without a doubt, in a privileged position to take such a leadership role, not only because of her/his understanding of the basics principles of new imaging modalities, but also because of her/his inherent participation in workflow design and educational/training activities. A well‐structured approach by the physicist will certainly lead the project to a successful completion, opening, in turn, new opportunities for the medical physicist to become an active participant in the decision‐making process for an institution. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811816

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

ESR dosimetry is widely used for several applications such as dose assessment in accidents, medical applications and sterilization of food and other materials. In this work the dosimetric properties of natural and synthetic Hydroxyapatite, Alanine, and 2‐Methylalanine are presented. Recent results on the use of a K‐Band (24 GHz) ESR spectrometer in dosimetry are also presented. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811817

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We designs and implement an instrumental methodology of analysis of the pupillary response to chromatic stimuli in order to observe the changes of pupillary area in the process of contraction and dilation in diabetic patients. Visual stimuli were used in the visible spectrum (400nm–650nm). Three different programs were used to determinate the best stimulation in order to obtain the better and contrasted pupillary response for diagnosis of the visual perception of colors. The stimulators PG0, PG12 and PG20 were designed in our laboratory. The test was carried out with 44 people, 33 men, 10 women and a boy (22–52 and 6 years), 12 with the stimulator PG0, 21 with PG12 and 17 with PG20, 7 subjects participated in more than a test. According to the plates of Ishihara, 40 of those subjects have normal vision to the colors, one subject suffers dicromasy (inability to differ or to perceive red and green) and while three of them present deficiencies to observe the blue and red spectrum (they suffer type II diabetes mellitus). With this instrumental methodology, we pretend to obtain an indication in the pupillary variability for the early diagnose of the diabetes mellitus, as well as a monitoring instrument for it. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811818

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Ultraviolet, violet and blue radiations have been widely applied to induce fluorescence of human tissues for diagnosis and detection of several diseases. Previous reports in this field have mainly been based on the use of laser sources. In this work, the feasibility of using UV and blue light emitting diodes (LED’s) in fluorescence analysis of human skin lesions is discussed. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811819

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

This paper presents some useful expressions for fading correction, which can be used in practical situations as they can be encountered in clinical dosimetry. The situations took into consideration can be encountered in hospital environments during and after radiotherapeutic treatments of patients as well as for radiation protection procedures concerning staff members. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1811820

出版商:AIP    

年代:1904

数据来源: AIP