Abstract：
:In a series of in vivo experiments on five adult canines, a small cylindrical permanent magnet (approximately 5-mm diameter x 5 mm long) was magnetically moved under fluoroscopic guidance from an occipital-lobe burr hole to a predetermined destination within the brain and then removed. On three of the animals, dorsal and temporal skull markers were used to establish a coordinate system against which the motions of the seed were referenced. These procedures were sufficiently accurate to permit the guided motion of the seed along nonlinear paths within the brain, including traversal of the midline through the corpus callosum. For removal, the seed could be steered either to a frontal lobe location for extraction through an auxiliary burr hole, or back to the same burr hole through which it had been inserted. This article discusses the way in which stereotactic motions were obtained, the performance limits of the instrumentation and the precision of motion achieved.
journal_name
Med Physjournal_title
Medical physicsauthors
Grady MS,Howard MA 3rd,Molloy JA,Ritter RC,Quate EG,Gillies GTdoi
10.1118/1.596520subject
Has Abstractpub_date
1990-05-01 00:00:00pages
405-15issue
3eissn
0094-2405issn
2473-4209journal_volume
17pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:Although x-ray computed tomography (CT) has been in clinical use for over 3 decades, spectral optimization has not been a topic of great concern; high voltages around 120 kV have been in use since the beginning of CT. It is the purpose of this study to analyze, in a rigorous manner, the energies at which the patient d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3075901
更新日期：2009-03-01 00:00:00
abstract：:We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four l...
journal_title：Medical physics
pub_type： 临床试验,杂志文章
doi：10.1118/1.1809778
更新日期：2004-12-01 00:00:00
abstract：PURPOSE:In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS:The presented edge illumination system is based o...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14553
更新日期：2020-10-27 00:00:00
abstract：:Monte Carlo (MC) techniques can be used to build a simulation model of an electron accelerator to calculate output factors for electron fields. This can be useful during commissioning of electron beams from a linac and in clinical practice where irregular fields are also encountered. The Monte Carlo code BEAM/EGS4 was...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1373402
更新日期：2001-06-01 00:00:00
abstract：PURPOSE:For cone-beam computed tomography (CBCT) systems, we propose a sphere phantom based method to estimate the full three-dimensional (3D) modulation transfer function (MTF). METHODS:The FDK reconstruction of CBCT system in a local region was modeled by a triple convolution operator. Afterward, we calculated the d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14147
更新日期：2020-07-01 00:00:00
abstract：:Interstitial brachytherapy for carcinoma of the prostate is achieved through the use of a configuration of radioactive seeds placed in a manner that delivers a customized, reasonably uniform dose to the target volume. Accurate dose delivery depends on both precise seed placement and reliable seed strength in the impla...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598877
更新日期：2000-01-01 00:00:00
abstract：PURPOSE:The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4955121
更新日期：2016-08-01 00:00:00
abstract：:In the case of non-small cell lung cancer, doses typically prescribed (60-66 Gy) are not sufficient to ensure a satisfactory tumor control probability. Dose escalation needs to be realized, but dose to organs at risk (OARs) must be kept under widely accepted clinical thresholds. Also, lung functionality is not homogen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2965976
更新日期：2008-07-01 00:00:00
abstract：:The Anisotropic Analytical Algorithm (AAA) of the Varian Eclipse treatment planning system calculates absolute dose for a variety of beam settings including those with an enhanced dynamic wedge (EDW). This algorithm has gone through a number of version updates since it was first released in July 2005. Previous version...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2965929
更新日期：2008-07-01 00:00:00
abstract：PURPOSE:A major challenge of four dimensional computed tomography (4DCT) in treatment planning and delivery has been the lack of respiration amplitude and phase reproducibility during image acquisition. The implementation of a prospective gating algorithm would ensure that images would be acquired only during user-spec...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3556589
更新日期：2011-03-01 00:00:00
abstract：:Nuclear Magnetic Resonance (NMR) permits the noninvasive measurement of blood flow signals unimpaired by clothes, bandages, casts, etc. The cylindrical crossed-coil NMR blood flowmeter was used to measure blood flow through a cross-section of the human forearm. Two calibration procedures are described: one for pulsati...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594989
更新日期：1981-07-01 00:00:00
abstract：PURPOSE:The authors use reduced-order constrained optimization (ROCO) to create clinically acceptable IMRT plans quickly and automatically for advanced lung cancer patients. Their new ROCO implementation works with the treatment planning system and full dose calculation used at Memorial Sloan-Kettering Cancer Center (M...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3575416
更新日期：2011-05-01 00:00:00
abstract：:Nuclear magnetic resonance (NMR) imaging of perfluorocarbon (PFC) emulsions and neat liquids has shown potential for in vivo oxygen imaging in blood and organ tissue. PFC compounds exhibit complicated NMR spectra caused by chemical shifts and spin-spin couplings which can lead to artifacts and degraded spatial resolut...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595960
更新日期：1986-07-01 00:00:00
abstract：PURPOSE:To compare esophageal dose distributions in esophageal sparing IMRT plans with predicted dose distributions which include the effect of inter-fraction motion. METHODS:Seven lung cancer patients were used, each with a standard and an esophageal sparing plan (74Gy, 2Gy fractions). The average max dose to esophag...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735647
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The lateral edge of a proton therapy beam is commonly used to achieve conformality to the treatment volume where critical structures reside close to the target. However, when treating shallow depths, the lateral edge of a pencil beam scanning (PBS) system may be broader than that of a double scattered (DS) syst...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4941957
更新日期：2016-03-01 00:00:00
abstract：PURPOSE:To construct a Monte Carlo (MC)-based simulation model for analyzing the dependence of tumor oxygen distribution on different variables related to tumor vasculature [blood velocity, vessel-to-vessel proximity (vessel proximity), and inflowing oxygen partial pressure (pO2)]. METHODS:A voxel-based tissue model c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892386
更新日期：2014-09-01 00:00:00
abstract：PURPOSE:In this study, we evaluated the degree of consistency between size metrics obtained from PEM and MRI to determine the intrinsic effectiveness of a multimodality approach using these two systems for breast imaging. METHODS:Under an IRB-approved protocol, 42 cases were considered (16 patients with 28 lesions), e...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735979
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:On-board MRI can provide superb soft tissue contrast for improving liver SBRT localization. However, the availability of on-board MRI in clinics is extremely limited. On the contrary, on-board kV imaging systems are widely available on radiotherapy machines, but its capability to localize tumors in soft tissue ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12998
更新日期：2018-07-01 00:00:00
abstract：:A double-mirror multilayer monochromator was developed for the purpose of irradiating live cell cultures at the Synchrotron Radiation Center, University of Wisconsin-Madison. The monochromator is designed for the soft x-ray region with photon energies between 270 and 2400 eV. Multilayer mirrors with 55 bilayers of W/C...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598259
更新日期：1998-05-01 00:00:00
abstract：:An artificial neural network using input data derived from attenuation measurements was trained to generate spectral profiles (relative number of photons versus energy). Once the relative spectral distribution is reconstructed, absolute spectra (number of photons per unit exposure spectral distribution is reconstructe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596495
更新日期：1990-07-01 00:00:00
abstract：:While simple, intravascular brachytherapy (IVB) presents a considerable potential for harm to the patient. The medical physicist maintains the responsibility to minimize the likelihood of operational problems or dosimetric errors. The principals for safe operation remain the same as with any radiotherapy treatment: to...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1524167
更新日期：2002-12-01 00:00:00
abstract：:The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the con...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1312190
更新日期：2000-10-01 00:00:00
abstract：PURPOSE:To investigate the geometry dependence of the detector response function (DRF) of three commonly used scanning ionization chambers and its impact on a convolution-based method to address the volume averaging effect (VAE). METHODS:A convolution-based approach has been proposed recently to address the ionization...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4944783
更新日期：2016-05-01 00:00:00
abstract：PURPOSE:The liver segments divided by Couinaud classification method are used to understand the functional anatomy of liver, which is significant in hepatic resection surgery. In Couinaud classification method, each third-order branch of the portal vein (PV) defines the supplied territory of a corresponding liver segme...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14745
更新日期：2021-02-02 00:00:00
abstract：:The dose received in the buildup region outside the primary beam has been measured for 60Co gamma rays and 6- and 18-MV X rays. The variation of this dose with field size and depth was evaluated. The effect of blocking trays and the importance of their design was determined. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595508
更新日期：1984-05-01 00:00:00
abstract：:In this paper a novel technique is proposed and validated for radiosurgery treatment planning of arteriovenous malformations (AVMs). The technique was developed for frameless radiosurgery by means of the CyberKnife, a nonisocentric, linac-based system which allows highly conformed isodose surfaces to be obtained, whil...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1751252
更新日期：2004-06-01 00:00:00
abstract：:In previous work it has been shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, it is demonstrated that an artificial neural network (ANN) trained on a s...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597586
更新日期：1995-05-01 00:00:00
abstract：:A new factor for shifting isodoes curves for oblique Co-60 photon beams has been deduced. Like the two other known factors, this shift factor depends on the source-to-surface distance (SSD), the depth dose (D) and the derivative of D with depth. A comparison of corrected dose distributions has been made by using the t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594688
更新日期：1980-05-01 00:00:00
abstract：:This study proposes an algorithm for selecting beam weight, wedge angle, and wedge orientation for three-dimensional radiation therapy treatment planning. According to dose gradient analysis, the necessary and sufficient condition for achieving a homogeneous dose over the target volume is that the total vector sum of ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1286591
更新日期：2000-08-01 00:00:00
abstract：PURPOSE:The purpose of this work was to generate uncompressed heterogeneous breast phantom models using size-dependent fibroglandular distributions derived from a large cohort of breast CT (bCT) datasets, and to compare differences in normalized glandular dose coefficients for bCT "DgNCT " when the realistic heterogene...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13391
更新日期：2019-03-01 00:00:00
