✓ This paper describes the use of three-dimensional computer graphics to display structures visible in computerized tomography (CT) scans and accurately determine optimum stereotaxic probe placement relative those structures. A prototype Lucite frame designed for CT body scanners was fitted with a phantom consisting small spheres representing intracranial tumors diameters 6 19 mm. series obtained together. Edge outlines were extracted from each scan series. visual representation by...

A prototype stereotactic head frame has been constructed for use in conjunction with a computed tomographic (CT) body scanner. Interactive software developed to allow target delineation using standard CT scanner computer and image display console. The mathematic equations fundamental this are described. In preliminary experiments, it demonstrated that can accurately direct probe an appropriately delineated series of scans. theoretic method determining accuracy is presented; results suggest...

A clinical stereotaxic head frame designed for use with computed tomography (CT) body scanners is described. Frame geometry and a CT localization system provide an accuracy versatility that should lead to optimal usefulness. Initial phantom studies are presented.

The original description of the k-d tree recognized that rebalancing techniques, such as are used to build an AVL or a red-black tree, not applicable tree. Hence, in order balanced it is necessary find median data for each recursive subdivision those data. sort selection strongly influences computational complexity building This paper discusses alternative algorithm builds by presorting k dimensions prior It then preserves these sorts during construction and thereby avoids requirement any...

We evaluated the effects of a large (920 cal) liquid carbohydrate (CHO) load on maximum exercise capacity 18 patients with chronic airflow obstruction [forced expiratory volume at 1 s (FEV1) = 1.27 +/- 0.48 liters; FEV1/forced vital 0.41 0.11]. Patients underwent duplicate incremental cycle ergometer tests to symptom-limited following CHO and placebo in single-blind fashion. Expired gas measurements were obtained during each power output. In 12 arterial blood gases measured, six venous was...

Abstract Generalized Born solvation models offer a popular method of including electrostatic aspects free energies within an analytical model that depends only upon atomic coordinates, charges, and dielectric radii. Here, we describe how second derivatives with respect to Cartesian coordinates can be computed in efficient manner distributed over multiple processors. This approach makes possible variety new methods analysis for these implicit models. We illustrate three here: the use...

A system has been developed for using computed tomography to direct stereotactic neurosurgical procedures. This operates with many commercially available CT body scanners and does not require any modification be made either the scanner or its computer software. The use of this rigid fixation patient nor meticulous positioning in scanner.

The N-localizer, which facilitates computed tomography-guided stereotactic surgery, was invented in the late 1970s by a medical student who built prototype frame to test concept. Initial experiments using were soon followed surgery humans Brown-Roberts-Wells frame.

Cerebral astrocytomas and undifferentiated gliomas were graded by (1) Kernohan classification on the basis of visual microscopy, (2) optical density/area profiles obtained automated densitometry with a Quantimet 720 image-analysing computer. In retrospective study 44 patients measurements seemed to give more accurate assessment prognosis than grading.

The N-localizer enjoys widespread use in image-guided stereotactic neurosurgery and radiosurgery. This article derives the mathematical equations that are used with three N-localizers provides analogies, explanations, appendices order to promote a deeper understanding of principles govern N-localizer.

The N-localizer and the Sturm-Pastyr localizer are two technologies that facilitate image-guided stereotactic surgery. Both localizers enable geometric transformation of tomographic image data from two-dimensional coordinate system a medical into three-dimensional frame. Monte Carlo simulations reveal is less accurate than in presence noise.

Introduction: Frame-based stereotaxis has been widely utilized for precise neurosurgical procedures throughout the world nearly 40 years. The N-localizer is an integral component of most extant systems. Analysis targeting errors related to not carried out in sufficient detail. We highlight these potential and develop methods reduce them. Methods: systems comprising three four N-localizers various geometries were analyzed using Monte Carlo (MC) simulations. simulations included native altered...

The mathematics that were originally developed for the N-localizer apply to three N-localizers produce sets of fiducials in a tomographic image. Some applications use four fiducials; however, do not fiducials. This article presents or more all lie within one planar In addition, these are extended image, as may be case with magnetic resonance (MR) imaging where volume is imaged instead series images. Whether applied image provide statistical measure quality data influenced by factors, such...

More than three decades after the invention of N-localizer, its origin remains misunderstood. Some are unaware that a third-year medical student invented this technology. This historical vignette provides an accurate chronicle and early history N-localizer.

A desktop microcomputer environment that utilizes Brown-Roberts-Wells (BRW) frame coordinates for creation of three-dimensional depiction operator-defined intracranial structures has been developed. The system allows direct reading Siemens CT scan images from a floppy disc, structural edge definition, and reconstruction defined images. is used in the operating room to view scans, perform standard BRW stereotactic functions, create graphics such tasks as defining tumor margins,...

In papers I, II, and III of this series the steady-state theory mutations was developed applied to extensive data on effect radiation beagles acquired here during past twenty years. paper is used interpret H. B. Dorn's incidence 21 kinds cancer in both male female Americans. The shows nature heterogeneity population various disorders. agreement found confirms an interesting way.