Tangential View Research Articles

The Detection of Prominent Hardware in Volar Locked Plating of Distal Radius Fractures: Intraoperative Fluoroscopy Versus Computed Tomography

To assess the utility of the dorsal tangential view (DTV) in detecting intraoperative dorsal screw penetration in distal radius fractures treated with volar locked plating. Retrospective cohort study. Academic level 1 trauma center. Skeletally mature patients where open reduction internal fixation with volar locked plating was the definitive treatment. A total of twenty-six patients were evaluated. Intraoperative anteroposterior, lateral, 20 degree tilted lateral, and DTVs were obtained through fluoroscopy in all wrists. Screw exchange and position by fluoroscopic view was recorded. A computed tomography (CT) was taken postoperatively to identify residual prominent screws. Data points included frequency of screw exchange by standard fluoroscopic views, the DTV, and residual prominent screws detected by CT. Eight constructs of thirty (27%) had prominent screws evident on the DTV but not seen on standard fluoroscopic analysis. CT identified 5 additional screws with ≥1 mm dorsal penetration not identified by the DTV. All except 1 screw was in the second dorsal wrist compartment. The DTV was 67% sensitive with a negative predictive value of 97%. It is risky and unnecessary to place bicortical screws in the distal part of a volar plate. Given that the DTV view was not sufficient to avoid dorsal screw prominence, distal screws should be intentionally 2-4 mm shorter than measured. Recent studies propose bicortical distal locking screws are not needed for sufficient construct stiffness in volar locked plating. We suggest caution when using this view to verify acceptable placement of screws in proximity to the second dorsal compartment. Diagnostic level III. See Instructions for Authors for a complete description of levels of evidence.

X-ray tangential view in diagnosis of fracture of the fifth metatarsal base

Objective To introduce a new X-ray projection in diagnosis of fracture of the fifth metatarsal base. Methods Included in this study were 97 patients who had undergone foot X-ray ex-amination at anteroposterior, oblique and tangential views from October 2014 to July 2015. They were 39 males and 58 females, with an average age of 46.2 years (from 15 to 80 years). Altogether, 43 left sides and 54 right sides were involved. In the tangential projection, the patients took supine position, kept the lower leg at extension and internal rotation of 10 to 20 degrees on the examination bed, relaxed the ankle on a resting position, kept the tube center to the fifth metatarsal base and perpendicular-to-table alignment. The fracture displacements were measured on the X-ray films of the 3 views. The Mehlhorn classifications and displace-ments observed on the tangential view X-ray films were compared with those on the X-ray films of anteropos-terior and oblique views. Results The fracture line was evident on the tangential view X-ray films of all the 97 patients but on the anteroposterior and oblique view films of 91 cases (93.8%). The mean fracture displacement on the tangential view films was greater than that on the anteroposterior and oblique view films. In the Mehlhorn classification, the anteroposterior view films revealed 59 cases of type A and 35 cases of type B; the oblique films showed 56 cases of type A and 38 cases of type B; the tangential view films found 35 cases of type A and 59 cases of type B. The tangential view films showed a significantly higher rate of diagnosis of type B fractures than images of the other 2 views (P<0.001). Conclusions The tangential pro-jection X-ray has an important value in the diagnosis of the fifth metatarsal base fracture. Patients suspected of the fracture should take X-ray examination at anteroposterior, oblique and tangential views. Key words: Metatarsal bones; Fractures, bone; Radiography; Diagnosis

Preliminary design of a tangentially viewing imaging bolometer for NSTX-U

The infrared imaging video bolometer (IRVB) measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 × 480 (1280 × 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm × 9 cm × 2 μm Pt foil. The foil is divided into 40 × 40 (64 × 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) μW/cm2 for a time resolution of 33 (20) ms. Synthetic images derived from Scrape Off Layer Plasma Simulation data using the IRVB geometry show peak signal levels ranging from ∼0.8 to ∼80 (∼0.36 to ∼26) mW/cm2.

Initial operation of a newly developed multichord motional Stark effect diagnostic in KSTAR.

A photo-elastic modulator based 25-chord motional Stark effect (MSE) diagnostic has been successfully developed and commissioned in Korea Superconducting Tokamak Advanced Research. The diagnostic measures the radial magnetic pitch angle profile of the Stark splitting of a D-alpha line at 656.1 nm by the electric field associated with the neutral deuterium heating beam. A tangential view of the neutral beam provides a good spatial resolution of 1-3 cm for covering the major radius from 1.74 m to 2.28 m, and the time resolution is achieved at 10 ms. An in-vessel calibration before the vacuum closing as well as an in situ calibration during the tokamak operation was performed by means of specially designed polarized lighting sources. In this work, we present the final design of the installed MSE diagnostic and the first results of the commissioning.

Femoral Condyles Tangential Views: An Effective Method to Detect the Screw Penetration of Femoral Condyles After Retrograde Nailing.

Background:Postoperative knee soft tissue irritation is a common complication after retrograde nail fixation of femoral fractures. Distal locking screw prominence is one of the causes for soft tissue irritation. This study aimed to determine whether the use of the femoral condyles tangential views improve the diagnostic accuracy compared with anteroposterior (A-P) view in detecting distal locking screw penetrations during retrograde femoral nailing.Methods:The angle between the sagittal plane and lateral aspect of the condyle and the angle between the sagittal plane and medial aspect of condyle were measured on computed tomography (CT) images. After the angles were measured and recorded, cadaveric femurs were used in a simulated surgical procedure. The retrograde femoral nail was inserted into the femur and placed distal locking screws, which were left 2, 4, and 6 mm proud of the medial and lateral condyles for each femur. A-P view, lateral condyle tangential view and medial condyle tangential view were obtained. All fluoroscopic images were recorded and sent to three observers blinded to the experimental procedure to determine whether screws penetrated the condyle cortex or not.Results:According to the results of CT scan, the lateral condyle view was 20.88 ± 0.98° and the medial condyle view was 40.46 ± 3.14°. In the A-P view, we detected 0% at 2 mm penetration, 16.7% (lateral condyle screw) and 25.0% (medial condyle screw) at 4 mm, and 41.7% (lateral condyle screw) and 58.3% (medial condyle screw) at 6 mm. In the lateral tangential view, we detected 91.7% at 2 mm penetration of the lateral condyle and 100% at 4 mm and 6 mm. In the medial tangential view, we detected 66.7% at 2 mm penetration of the medial condyle and 100% at 4 mm and 6 mm. The femoral condyle tangential views provided significant improvement in detecting screw penetrations at all lengths (2, 4, and 6 mm) compared with the A-P view (P < 0.05).Conclusions:The femoral condyles tangential views increased the accuracy of detecting screw penetrations on the medial and lateral condyles. Routine clinical use of the femoral condyles tangential views has the potential to increase accuracy in detecting distal locking screw penetration during retrograde femoral nailing.

Dorsal Screw Penetration With the Use of Volar Plating of Distal Radius Fractures

To evaluate the most vulnerable position at which volar plate screws may penetrate the dorsal cortex of the radius and to determine which specific intraoperative fluoroscopic images (lateral, 45 degrees supination, 45 degrees pronation, and dorsal tangential) are most useful to detect dorsal cortex penetration. Four 2.5-mm locking screws were inserted distally using 18-, 20-, or 22-mm screws in 7 cadaveric specimens apiece. The specimens were then evaluated to count the number of screws breaching the dorsal cortex and the amount of penetration. Lateral, 45 degrees supination, 45 degrees pronation, and dorsal tangential fluoroscopic views were taken of each wrist. Sixty-three orthopaedic surgeons of varying experience were then asked to evaluate whether the screws penetrated the dorsal cortex after viewing each image. Dorsal cortex screw penetration of at least 1 screw occurred in 3.6% of specimens with 18-mm screws, 25% of specimens with 20-mm screws, and 57% specimens with 22-mm screws. Radial-sided screws more commonly breached the dorsal cortex. The sensitivity was 58% on the lateral view, 88% on the 45 degrees supination view, 53% on the 45 degrees pronation view, and 67% on the dorsal tangential view. Additionally, surgeons with more experience were less accurate in detecting prominent screws. Clinicians should consider use of these views to evaluate dorsal screw penetration after volar plating but may opt to subtract a few millimeters from their measured screw lengths to avoid over penetration past the dorsal cortex.

Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures.

Background:Volar locking plate fixation has become the gold standard in the treatment of unstable distal radius fractures. Juxta-articular screws should be placed as close as possible to the subchondral zone, in an optimized length to buttress the articular surface and address the contralateral cortical bone. On the other hand, intra-articular screw misplacements will promote osteoarthritis, while the penetration of the contralateral bone surface may result in tendon irritations and ruptures. The intraoperative control of fracture reduction and implant positioning is limited in the common postero-anterior and true lateral two-dimensional (2D)-fluoroscopic views. Therefore, additional 2D-fluoroscopic views in different projections and intraoperative three-dimensional (3D) fluoroscopy were recently reported. Nevertheless, their utility has issued controversies.Objectives:The following questions should be answered in this study; 1) Are the additional tangential view and the intraoperative 3D fluoroscopy useful in the clinical routine to detect persistent fracture dislocations and screw misplacements, to prevent revision surgery? 2) Which is the most dangerous plate hole for screw misplacement?Patients and Methods:A total of 48 patients (36 females and 13 males) with 49 unstable distal radius fractures (22 x 23 A; 2 x 23 B, and 25 x 23 C) were treated with a 2.4 mm variable angle LCP Two-Column volar distal radius plate (Synthes GmbH, Oberdorf, Switzerland) during a 10-month period. After final fixation, according to the manufactures' technique guide and control of implant placement in the two common perpendicular 2D-fluoroscopic images (postero-anterior and true lateral), an additional tangential view and intraoperative 3D fluoroscopic scan were performed to control the anatomic fracture reduction and screw placements. Intraoperative revision rates due to screw misplacements (intra-articular or overlength) were evaluated. Additionally, the number of surgeons, time and radiation-exposure, for each step of the operating procedure, were recorded.Results:In the standard 2D-fluoroscopic views (postero-anterior and true lateral projection), 22 screw misplacements of 232 inserted screws were not detected. Based on the additional tangential view, 12 screws were exchanged, followed by further 10 screws after performing the 3D fluoroscopic scan. The most lateral screw position had the highest risk for screw misplacement (accounting for 45.5% of all exchanged screws). The mean number of images for the tangential view was 3 ± 2.5 images. The mean surgical time was extended by 10.02 ± 3.82 minutes for the 3D fluoroscopic scan. An additional radiation exposure of 4.4 ± 4.5seconds, with a dose area product of 39.2 ± 14.5 cGy/cm2 were necessary for the tangential view and 54.4 ± 20.9 seconds with a dose area product of 2.1 ± 2.2 cGy/cm2, for the 3D fluoroscopic scan.Conclusions:We recommend the additional 2D-fluoroscopic tangential view for detection of screw misplacements caused by overlength, with penetration on the dorsal cortical surface of the distal radius, predominantly observed for the most lateral screw position. The use of intraoperative 3D fluoroscopy did not become accepted in our clinical routine, due to the technical demanding and time consuming procedure, with a limited image quality so far.

Clinically significant, nontraumatic, degenerative joint disease of the temporomandibular joints in a horse

SummaryHorses with degenerative joint disease (DJD) of the temporomandibular joint (TMJ) have been reported infrequently, with the majority of cases describing the disease as a consequence of an earlier traumatic event. A case of clinically significant TMJ‐DJD due to a nontraumatic event has not been published. This retrospective case report describes a case of bilateral, DJD of the TMJ. Case management, subsequent review and interpretation of the clinical records, tangential radiographic views of each TMJ, computed tomography and magnetic resonance imaging of the head, and post mortem histological examination of the TMJs were performed. The horse exhibited both quidding and a ‘clicking’ sound during mastication; episodes of intermittent colic were also prevalent in the horse's history. Computed tomography illustrated bilateral mineralisation of the rostral aspect of both intra‐articular discs. Treatment, by intra‐articular injection of corticosteroid, resulted in temporary resolution of both the quidding and the ‘clicking’ sound, as well as the recurrent episodes of colic. Repeated treatment over time was required. Ultimately the horse was subjected to euthanasia for reasons other than disease of the TMJ. The development of TMJ‐DJD may not be confined to traumatic events. Age‐related degeneration of this joint may occur and manifest through quidding and abnormal sounds noted during mastication.

Physical examination and imaging of medial collateral ligament and posteromedial corner of the knee.

The medial collateral ligament (MCL) is the most commonly injured knee ligament. Most will heal well with nonoperative treatment. However, not all medial knee injuries are the same. A detailed physical examination can help determine the severity of the medial-sided injury. When combined with advanced imaging, the examination will delineate damage to associated medial knee structures, including the location of MCL damage, posteromedial capsule injuries, and combined cruciate injuries. Failure to recognize MCL injuries that may be prone to chronic laxity can lead to significant disability, joint damage, and failure of concomitant cruciate ligament reconstructions. Magnetic resonance imaging is the mainstay of diagnostic imaging, with coronal sequences allowing full assessment of the MCL complex. Tangential views aid in the diagnosis of concomitant injuries. Stress radiography can play a role in evaluating MCL healing and subtle chronic laxity. Ultrasonography is also gaining acceptance as a means to assess MCL injuries. Use of a detailed examination and advanced imaging will allow optimal treatment of medial knee injuries and improve clinical outcomes.

Anatomy and radiology of the back zone of acetabular posterior column

Objective To characterize the clinical anatomy and radiology of the acetabular posterior column and to explore their significance for lag screw fixation of the acetabular posterior column. Methods This study was carried out on the axial magnetic resonance imaging of 20 right and left pelves of 10 adult males, aged from 24 to 67 years (mean, 36.1 years). The parameters were measured on the plane of the ischial spine apex (P1) and the plane 5 millimeters above P1 (P2). Five lines were drawn to simulate the fluoroscopy at the anteroposterior, iliac oblique and obturator oblique views. Line 2 and line 3 intersected the posterior aspect of the posterior column at points A and B, respectively. Line 1 intersected line 2 and line 3 at points D and G, respectively. Point E was the midpoint of CD. EF was perpendicular to CD, and intersected the posterior aspect of the posterior column at point F. On P1 and P2, the lengths of AD (al, a2) and EF (bl, b2) and the shortest distance between the front edge of the sciatic nerve and the posterior column were measured (L1, L2). Last, the position of the sciatic nerve relative to the quadrilateralABCDwas surveyed. Results The shape of the shadow is akin to a right-angled trapezoid. The parameters of the shadow areaare as follows: al = 11.62±2.29 mm, bl = 9.24±1.64 mm, a2 = 13.63±1.85 mm, b2 = 9.01±1.94 min. The distances between the nerve and the posterior column are as follows: L1 = 7.42±1.90 mm, and L2 = 5.83±1.93 mm. On P1, 85% of the sciatic nerve is in the shadow (40% in R1 and 45% in the junctional zone of R1 and R2) and just 15% is out of the shadow area. On P2, 85% of the sciatic nerve is in the R1 region and just 15% is out of the shadow area. Conclusions Since bony structure of the acetabular posterior column is irregular and the distance between the sciatic nerve and the posterior column is very limited, it is likely that the sciatic nerve may be injured by a lag screw. As it is not enough to define positions of a lag screw by 3 fluoroscopic views, tangential view of the posterior column or navigation technology can help implant a lag screw accurately. Key words: Acetabulum; Bone nails; Sciatic nerve; Fluoroscopy; Shadow area

A New Measure of Tibial Sesamoid Position in Hallux Valgus in Relation to the Coronal Rotation of the First Metatarsal in CT Scans.

We aimed to find a new radiographic measurement for evaluating first metatarsal pronation and sesamoid position in hallux valgus (HV) deformity. Data from a clinical study of 19 control patients (19 feet) with no HV deformity were compared with preoperative data of 138 patients (166 feet) with HV deformities. Using a weightbearing plain radiograph in anteroposterior (AP) view, the intermetatarsal angles (IMAs) and the hallux valgus angles (HVAs) of the control and study groups were measured. Using a semi-weightbearing coronal computed tomography (CT) axial view, the α angle was measured in the control and study groups. In addition, the tibial sesamoid grades in plain radiograph tangential view and the CT axial view were measured. The tibial sesamoid position in an AP view was checked preoperatively. Based on these measurements, 4 types of HV deformities were defined. The mean values of the α angle in the control and HV deformity groups (control group µ = 13.8 degrees, study group µ = 21.9 degrees) was significantly different. Among 166 HV feet, 145 feet (87.3%) had an α angle of more than 15.8 degrees, which is the upper value of the 95% confidence interval of the control group, indicating the existence of abnormal first metatarsal pronation in HV deformity. Four types of HV deformities were defined based on their α angles and tibial sesamoid grades in CT axial view (CT 4 position). Among 25.9% (43/166) of the study group, abnormal first metatarsal pronation with an absence of sesamoid deviation from its articular facet was observed. The prominent characteristic of this group was that they had high grades in the AP 7 position (≥5); however, in the CT 4 position, their grade was 0. This group was defined as the "pseudo-sesamoid subluxation" group. Patients with HV deformities had a more pronated first metatarsal than the control group, with a greater α angle. Pseudo-subluxation of the sesamoids existed in 25.9% of our study group. From our results, we suggest that the use of the CT axial view in assessments of HV deformity may benefit surgeons when they make operative choices to correct these deformities. With regard to the pseudo-sesamoid subluxation group, the use of the distal soft tissue procedure is not surgically recommended. Level III, retrospective comparative study.

Dynamic Anatomy of Aortic Root and Its Potential Role in TAVR Prostheses Further Development and Modification

Aortic stenosis (AS) is the most common valvular disorder. Surgical aortic valve replacement is the definitive therapy for patients with severe AS. In the last years transcatheter aortic valve replacement (TAVR) has been developed as an alternative to surgical aortic valve replacement with promising results. Despite being less invasive than open-chest aortic valve replacement, good outcome and effectiveness of TAVR procedure, it remains associated with the potential for serious complications and short-time durability. Today there are two TAVR prostheses that have CE marks and FDA approved: Edwards Valves and CoreValve. Besides there are many other newly developed TAVR prostheses on the stage of clinical trials. However, no one of them had been developed on the base of data for dynamic anatomy of human aortic root because of the lack of appropriate imaging modality. Today, different two-dimensional (2D) and three-dimensional (3D) imaging techniques are used for aortic root examination. But no one of them has been accepted as a “gold standard” imaging modality for assessment of dynamic anatomy of aortic root. The existing imaging modalities such as transthoracic echocardiography, transesophageal echocardiography, angiography, CT and MRI scans provide tangential cut plane view which did not reflect the real sizes of the annulus and other aortic root rings and structures. Obtained with these modalities images did not reflect the changes of the size and shapes of the anatomic structures of aortic root during the different phase of cardiac cycles either. Today there are strict needs for imaging Mini-review Article Zarayelyan; BJMMR, 5(12): 1534-1546, 2015; Article no.BJMMR.2015.173 1535 modality which could assist in assessment of dynamic aortic root to push the TAVR prosthesis design and modification on new level.

The Dorsal Tangential X-Ray View to Determine Dorsal Screw Penetration During Volar Plating of Distal Radius Fractures

To evaluate whether the dorsal tangential view (DTV) allows for reliable and valid in vivo measurement of the distance between screw tips and the dorsal radial cortex (STCD) during volar plating of distal radius fractures. Subjects included 22 patients with displaced distal radius fractures who had volar plate osteosynthesis. We performed standardized DTV images intraoperatively. After surgery, we performed computed tomography (CT) scans with reconstructions parallel to the distal screws. Three independent observers blinded to the study protocol measured the STCD on the basis of the DTV images and CT reconstructions. We calculated inter- and intraobserver reliability and the correlation between STCD values measured with DTV images and CT scans. Eleven screws were changed intraoperatively. We observed no cases of postoperative screw perforations. Inter- and intraobserver reliability of STCD measurement was good when measured with DTV images and excellent when measured on the basis of CT reconstructions. Statistical analysis showed a good correlation between mean STCD values measured with DTV and CT. The DTV allowed in vivo evaluation of the dorsal radial cortex and enabled reliable assessment of the distance between the screw tip and the dorsal cortex. It may allow detection of dorsal screw perforation during volar plating of distal radial fractures.

Fluoroscopic views for safe insertion of lag screws into the posterior column of the acetabulum.

BackgroundPercutaneous lag screw fixation is an alternative treatment for non-displaced or minimally displaced posterior column fractures. This study aims to explore new fluoroscopic views of the acetabulum for safe percutaneous insertion of posterior column lag screws.MethodsAxial computed tomography (CT) scans were taken of sixteen embalmed adult cadavers. The axial CT images at the level of the middle height of the acetabulum were selected. The angle (angle α) between the posterior cortex of the posterior column (PCPC) and the line intersecting the axial plane and the coronal plane, and the angle (angle β) between the medial wall and the line intersecting the axial plane and the sagittal plane were identified and measured. Tangential views of the PCPC and medial wall were obtained by referencing the measured angles. A lag screw was inserted into the posterior columns of the sixteen pelvic specimens under fluoroscopic guidance using an iliac oblique view and the two tangential views. CT scans were performed to evaluate the lag screw position. Axial CT images of 52 volunteers were obtained and the angles α and β were measured following the same methods used for the cadaveric specimens.ResultsThe angles α and β for the specimens were 29.3±2.8.1 and 8.1±1.4 degrees, respectively. On the tangential view of the PCPC, the posterior cortex appears as a nearly straight line between the lesser and greater sciatic notches. On the tangential view of the medial wall, the medial wall appears as a distinct straight line. Using these radiographic images, the lag screws were inserted into the posterior columns of bony pelvic specimens. Screw placement was confirmed by CT, and found to be fully intraosseous in all cases without any cortical breaches. The angles α and β were 30.4±4.1 and 9.2±1.9 degrees for male volunteers and 28.5±3.7 and 7.7±1.8 degrees for female volunteers, significant difference in these angles between cadaveric specimens and human volunteers.ConclusionThe tangential views of both the PCPC and medial wall can be obtained following the aforementioned methods The oblique iliac view and the two tangential views enable safe insertion of posterior column lag screws.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-303) contains supplementary material, which is available to authorized users.

Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D.

An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in diverted and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. Demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.

ELCS in Ice: Cryo-electron Microscopy of Nuclear Envelope-Limited Chromatin Sheets

Nuclear envelope-limited chromatin sheets (ELCS) form during excessive interphase nuclear envelope growth in a variety of cells. ELCS appear as extended sheets within the cytoplasm connecting distant nuclear lobes. Cross-section stained images of ELCS, viewed by transmission electron microscopy, resemble a sandwich of apposed nuclear envelopes separated by ∼30 nm, containing a layer of parallel chromatin fibers. In this study, the ultrastructure of ELCS was compared by three different methods: (1) aldehyde fixation/dehydration/plastic embedding/sectioning and staining, (2) high-pressure freezing/freeze substitution into plastic/sectioning and staining, and (3) high-pressure freezing/cryo-sectioning/cryo-electron microscopy. ELCS could be clearly visualized by all three methods and, consequently, must exist in vivo and are not fixation artifacts. The ∼30-nm chromatin fibers could only be observed following aldehyde fixation; none were seen in cryo-sections. Electron microscopic tomography tangential views of aldehyde-fixed ELCS suggested an ordering of the separate chromatin fibers adjacent to the nuclear envelope. Possible mechanisms of this chromatin ordering are discussed.

Instrumentation for a multichord motional Stark effect diagnostic in KSTAR.

The motional Stark effect (MSE) diagnostic is used to measure the radial magnetic pitch angle profile in neutral beam heated plasmas. This information is used to calculate the safety factor, q, with magnetic equilibrium reconstruction codes such as EFIT. The MSE diagnostic is important during active shaping of the q profile to optimize confinement and stability, and it has become a key diagnostic in high performance tokamaks. A multichord photo-elastic modulator (PEM) based MSE system is being developed for a real-time plasma current profile control in Korea Superconducting Tokamak Advanced Research (KSTAR). The PEM-based approach is a standard method that measures the polarization direction of a single Stark line with narrow tunable bandpass filters. A tangential view of the heating beam provides good spatial resolution of 1-3 cm, which provides an opportunity to install 25 spatial channels spanning the major radius from 1.74 m to 2.84 m. Application of real-time control is a long-term technical goal after commissioning the diagnostic in KSTAR, which is expected in 2015. In this paper, we describe the design of this newly-constructed multichord MSE diagnostic in KSTAR.

DURABILIDAD NATURAL Y DESCRIPCIÓN ANATÓMICA DE LA MADERA DE LA ESPECIE Caryodaphnopsis cogolloi Van der Werf

La revista Colombia Forestal publica manuscritos originales en temáticas del campo forestal y diversos aspectos de los recursos naturales y del medio ambiente, los cuales se discriminan en las categorías de artículo de investigación, de revisión, de reflexión y notas técnicas de acuerdo con lo estipulado por COLCIENCIAS para las publicaciones científicas. De acuerdo a la clasificación de áreas científicas de la Organización para la Cooperación y el Desarrollo Económico (OCDE), la revista Colombia Forestal pertenece al gran área de Ciencias Agrícolas(4), área de Agricultura, Silvicultura y Pesca(4A) y a la disciplina Forestal (4A02).

A comparative study about ionizing radiation emitted during radiological “skyline” view of the wrist in pronation versus supination

The dorsal tangential view to the distal radius or "skyline," used to control the length of the screws for the ORIF with volar plates, is carried out in supination (fluoroscope vertical) or in pronation (fluoroscope horizontal). The purpose of this study was to compare the dose of ionizing radiation emitted during a "skyline" view in supination versus pronation. A "skyline" was performed on 14 fresh cadaveric wrists. In group 1, the fluoroscope was positioned vertically and the wrist was held in supination. In group 2, the fluoroscope was positioned horizontally and the wrist held in pronation. The average dose of ionizing radiation was 0.9286 cGy/cm(2) (group 1) and 0.8751 cGy/cm(2) (group 2). The difference was not statistically significant. Overall, the emitted dose for the "skyline" is negligible compared to that of a standard wrist radiography with no difference between the vertical and horizontal positioning. Peroperatively, the vertical "skyline" seems easier to setup, less time consuming and less prone to asepsis faults.

Real-time optical plasma boundary reconstruction for plasma position control at the TCV Tokamak

A dual, high speed, real-time visible light camera setup was installed on the TCV tokamak to reconstruct optically and in real-time the plasma boundary shape. Localized light emission from the plasma boundary in tangential view, broadband visible images results in clearly resolved boundary edge-features. These projected features are detected in real-time and transformed to the poloidal plane to obtain a measurement of the plasma boundary. Plasma boundary reconstructions of diverted plasma discharges are presented, showing agreement of within 1 cm compared with magnetic equilibrium reconstruction. The resulting real-time plasma shape measurement is applied in a feedback control loop for the plasma position, demonstrating effective stabilization and tracking of the plasma vertical position.