ABSTRACT
In this paper, a contactless positioning system is presented which has been designed to monitor the kinematic behavior of mechanical discontinuities in three dimensions. The positioning system comprises a neodymium magnet, fixed on one side of a discontinuity, and a magnetoresistive sensing array, fixed on the opposing side. Each of the anisotropic magnetoresistive sensors in the sensing array records the magnetic field along three orthogonal directions. The positioning system intrinsically generates compact data packages which are transmitted effectively using a range of standard wireless telecommunication technologies. These data are then modeled using a global least squares fitting procedure in which the adjustable parameters are represented by the position and orientation of the neodymium magnet. The instrumental resolution of the positioning system can be tuned depending on the strength of the magnetic field generated by the neodymium magnet and the distance between the neodymium magnet and the magnetoresistive sensing array. For a typical installation, the displacement resolution is shown to be circa 10 µm while the rotation resolution is circa 0.1°. The first permanently deployed positioning system was established in June 2016 to monitor the behavior of an N-S trending fault located at the contact between the eastern Alps and the Vienna Basin. The robust design of the positioning system is demonstrated by the fact that no interruptions in the broadcasted data streams have occurred since its installation. It has a range of potential applications in many areas of basic and applied research including geology, geotechnical engineering, and structural health monitoring.
ABSTRACT
Introduction: Stereotactic radiosurgery allows the treatment of small lesions, giving only one hypo-fractioned, radiation dose, according to the conditions of targeted tissues and other external factor to the patient. In our case, the photon field is generated in a linear electron accelerator. Radiation beams to treat small lesions are formed by a micro collimator (mMLC). Methods: A linear accelerator and a micro collimator were used when implementing the technique. Two ionization chambers, a diode and an electrometer were also used. Data was registered on an IBA Brand water phantom. The dosimetry parameters measured were: radiation transmission through the laminated sheets, absolute dosimetry (water and air) and relative dosimetry (PDD and profiles). These parameters follow the Data recollection guide for Apex and Monaco. Results: The transfer values were set at 0.60% in the CAX, 0.39% and 0.34% in the extremes established by protocol. Data obtained with the output factors adjust, in an optimum way, the curve for each measurement and corresponding field range. After filtering the data in an Omnipro software, the tendency line is now comparable with the references from Elekta. Every PDD with its own field range and every profile obtained were approved by the modelers. Discusion: Setting up the micro collimator system in radiosurgery begins with satisfactory test results and is then ready to offer treatment to patients at this hospital. The documentation delivered by Elekta's modeler physicist includes a simulation algorithm pack, the machine's geometrical parameters, verification and calibration data and measured data.
Subject(s)
Radiotherapy , Radiosurgery , DosimetryABSTRACT
El objetivo del presente trabajo es difundir en la comunidad médica el acrónimo SCIWORA y destacar la importancia de la Resonancia Magnética (RM) como herramienta sensible para su diagnóstico. Esta entidad se caracteriza por una lesión traumática de la médula espinal, en ausencia de anormalidad radiológicamente demostrable. Es única en niños, generalmente en menores de 8 años, con una incidencia estimada en 3,3% y 32 %. Esta brecha estadística se explica, en parte, por la edad de los grupos, el sitio donde reciben atención médica y particularmente por el acceso a la RM. Las lesiones medulares traumáticas son infrecuentes en la edad pediátrica y presentan el 5 % de todas las lesiones del raquis. La existencia de SCIWORA se explica por las condiciones anatómicas y biomecánicas del raquis en niños de esta edad.
The aim of this manuscript is to clarify the acronym SCIWORA among the medical community, and to highlight the importance of magnetic resonance imaging (MRI) as a sensitive tool for the diagnosis of this condition. SCIWORA is characterized by spinal cord injury, with normal radiology. It can only be diagnosed by MRI, although there is some controversy on this concept. It only occurs in children under 8 years of age, with an incidence ranging between 3.3% and 32%, which depends on age of the patient, degree of complexity of the health center and especially the access to MRI. Traumatic spinal cord injuries are rarely found in children, and account for 5% of all spinal lesions. In children, the presence of SCIWORA is associated with the anatomical and biomechanical characteristics of the spine.
ABSTRACT
Se presenta a un paciente de sexo femenino de 27 años de edad con el cuadro clásico de Síndrome de Mc Cune- Albright, caracterizado por: pubertad precoz, manchas color café con leche, displasia fibrosa poliostótica y gigantismo. Se describen los hallazgos en Resonancia Magnética de la región craneofacial y del raquis.
We report on a 27-year-old female with the classical McCune-Albright syndrome. This condition is characterized by precocious puberty, café-au-lait spots, polyostotic fibrous dysplasia and gigantism. MR findings are described in skull, face and spine.
ABSTRACT
La hidatidosis ósea es rara, representando el 0,5- 4% del total de localizaciones y se caracteriza por un curso insidioso con un largo periodo de latencia, diagnosticándose en estadios muy avanzados. Se presenta un caso de hidatidosis del fémur con extensión extraósea en un varón de 62 años de edad, agricultor, con fractura patológica, en ocasión de un accidente vial, siendo los hallazgos radiológicos sugestivos de malignidad. Se efectuó laboratorio y exéresis parcial del fémur, que permitió el diagnóstico de hidatidosis ósea.
Hydatidosis of bone is rare, accounting for only 0.5-4 % of cases in this topography. Is characterized by an insidious progression and a very large latency, therefore the disease being diagnosed at an advanced stage. This is the report of a case of the femur hydatidosis, in a 62- year-old man farmer, with pathological fracture, caused by a traffic accident. Radiographic findings suggest malignancy. Laboratory studies and a partial punction of femur were made with results for hydatidosis.
