Instrumented Needle Research Articles

Motorcycle Instrument Clusters for Collision Reconstruction

<div class="section abstract"><div class="htmlview paragraph">The behaviour of the instrument cluster of passenger cars during a collision is reasonably well understood, following a number of studies over the past decade. However, one of the frequent questions asked is if motorcycle instruments can be considered in the same way as passenger cars. Motorcycle instruments work in the same way as passenger car instruments. The older models use a Bowden cable to drive a spinning magnetic cup, which drags an instrument needle against a hair spring. Newer models (typically post 2000) use a stepper motor which requires power to drive the needle to any indicated position, including returning it to zero. Hence if power to the instrument is lost as a result of a collision, there is no electrical power to the motor to move the needle, and it should be left at its last position before the power was lost. However, the accelerations experienced by a motorcycle instrument during a collision are significantly different from those of an instrument cluster housed within the dash of a passenger car. Over the past few years a number of crash tests involving motorcycles have been carried out in the USA and UK and the behaviour of the instruments were analysed to see how they perform at holding any residual reading.</div></div>

HoloNeedle: Augmented Reality Guidance System for Needle Placement Investigating the Advantages of Three-Dimensional Needle Shape Reconstruction

Augmented reality (AR) systems have been proposed for medical needle procedures as alternatives to restore the physician's natural perspective and head motion parallax that are lost when using standard imaging methods. AR systems have assumed a rigid needle, but in practice, a needle can experience large deflections that can lead to significant errors. We combine an instrumented needle that measures bending deflections with optical tracking of the needle base for precision and an AR system to provide users with precise three-dimensional rendering of needle motion and deflection inside a body. In controlled tests, users guided a needle through 7 cm of tissue phantom to reach a 2-mm diameter target. We found that displaying needle shape allows users significantly reduce placement errors when compared to the rigid needle assumption. In addition, a new display technique called tip tangent extrapolation, based on the sensed needle endpoint and direction, allowed users to further reduce errors resulting in 26% less error when compared to a rigid needle assumption.

Geometry-Based Model for U-Shaped Strain Gauges on Medical Needles.

The knowledge of needle location during insertions is essential for the success of interventional radiology procedures. As the needle is susceptible to undergo deformations during its insertion into tissues, several methods have been proposed to monitor the needle deformed shape. Thus, instrumented needles with U-shaped strain gauges are currently being developed to reconstruct the shape of the needle from gauge acquisitions. These acquisitions are used in combination with gauge model to obtain estimate of the strain of the needle. The current modeling is limited as it does not consider the geometry of the gauge. This paper introduces a more complete model for U-shaped strain gauge which, unlike the current model, takes into account the width of the gauge. Thus, the impact of width modeling on the strain estimate can be measured and used to improve strain estimation accuracy. Results with real characteristics of instrumented needle devices show that the differences of strain estimate are around few percents. Finally, by taking into account the width and the length of the gauge our model includes the effets of the gauge size on the strain estimation and makes the miniaturization of the gauge less necessary.

Advanced sensors placement for accurate 3D needle shape reconstruction.

Needles are tools widely used in minimally invasive surgery. During such procedures the localization of the needle and its tip is a challenging situation because of the needle deformations due to its interactions with tissues. To tackle this problem, instrumented needles with sensors have been currently developed to allow needle reconstruction and tip localization. In conventional surgery this difficulty is overcome by medical imaging. The interest in using an instrumented needle resides in the possible dispense of medical imaging. This papers develops new methods to reconstruct needles in three dimensions and to find the locations of sensors which minimizes the error of reconstruction of the needle. A notable feature of our method is that input data are based on real needle data, that should assure a better representation of reality. Reconstructions simulated with 22 gauge 200 mm long needles show that the localization of the needle tip is more accurate by 18% to 52% with optimal sensors positions compared to equidistant sensors positions.

Using a 3D needle–tissue force distribution basis to optimise the design of an instrumented needle

In this paper, we describe a method enabling to optimally position the strain microgauges of an instrumented needle using a 3D force distribution basis, in order to explain the forces applied on the needle during an intervention.

Limitation of Distortion in Friction Stir Welded (FSW) Panels Using Needle Peening

Friction stir welding (FSWing) induces residual stresses and distortions in welded structures. Such residual stresses reduce the fatigue life of welded components, while the induced distortions prevent the welding of large or thin components. In the present study, needle peening was used to induce additional residual stresses in 2.3-mm thick (FSWed) aluminum alloy (AA) 2024-T3 sheets. This was done with the objective to counterbalance the welding-induced stresses and thus reduce the overall stresses and distortions. The needle peening process, which stems from shot peening, consists of hammering a surface using cylindrical spherical ended shots sliding back and forth in a treatment head. An instrumented needle peening machine was used to carry out peening on as-received (or bare) and bead-on-plate FSWed AA2024-T3 material. In both cases, the width of the peening area corresponded to that of a typical weld. The influence of the peening process parameters such as needle size, applied power and travel speed on the surface quality and magnitude of the induced distortions were evaluated. The results indicate that, by increasing the needle diameter from 1.2 mm to 2.0 mm, the peening-induced deflection on bare sheet material increased by an average value of 27% while the roughness average, Ra, decreased by an average value of 47%. It was also found that a surface finish qualitatively similar to that of conventional shot peening could be obtained by using appropriate needle peening trajectories. Finally, needle peening with an applied power of 10% was sufficient for eliminating 37% of the welding-induced transverse curvature and 82% of the welding-induced longitudinal curvature.

Stress distributions inside intervertebral discs: the validity of experimental "stress profilometry'.

This paper evaluates a technique for measuring the distribution of compressive stress within cadaveric intervertebral discs. A strain-gauged pressure transducer, side-mounted near the tip of a 1.3 mm diameter needle, was inserted into cubes of disc tissue and into intact discs. Regardless of the position and orientation of the transducer within the tissue or disc, its output was found to be proportional to the compressive force applied to the specimen. The distribution of compressive stress was measured by pulling the instrumented needle through the specimen and the resulting stress profiles were reproducible to within 20 per cent. Profiles obtained at different applied loads showed a similar distribution of stress within the disc, suggesting that the compressive stress at any location and direction increased in proportion to the applied load. Since transducer output was also proportional to applied load, it was reasoned that it must be proportional to compressive stress within the disc. The average vertical compressive stresses acting on various regions within a disc were calculated from the stress profiles and multiplied by the cross-sectional area of each region: the resulting force was then compared with the known applied force in order to assess the calibration coefficient of the transducer. Agreement between the two forces was good, indicating that the calibration coefficient established in a saline bath was applicable to disc tissues also. However, artifactual stress peaks could be generated if the transducer was pulled across a bony asperity. It is concluded that the transducer measures the mean compressive stress acting upon it within disc tissues. Errors associated with the technique are small compared to differences in stress distributions which occur naturally, for example when intervertebral discs are loaded to simulate different postures in a living person.

A Course Indicator of Pointer Type for the Visual Radio Range Beacon System

A form of tuned-reed radio range beacon course indicator is described, called a reed converter, in which the course indications are not given by observing the two reed motions as heretofore, but by means of a zero-center pointer type indicating instrument. The motion of the two reeds generates small alternating voltages, which when rectified by oxide rectifiers and passed in opposing polarities through a zero-center indicating instrument, serve to give course indications by the deflection of the indicating instrument needle in the direction of deviation of the airplane from the course. Each reed converter unit consists of a polarized reed tuned to one of the beacon modulation frequencies. The reed vibrates between a set of driving coils which are supplied with the signal from the radio range, and also extends between a set of pickup coils, and generates a voltage in these coils. Since a null method of course indication is used, it is necessary to provide a signal volume indicator in the form of a 0-500 microammeter in the output circuit of the oxide rectifiers. Several forms of converter selector switch circuit arrangements are shown. The advantages and disadvantages of the reed converter as compared to the tuned reed indicator are discussed.

A course indicator of pointer type for the visual radio range-beacon system

A form of tuned-reed radio range beacon course indicator is described, called a reed converter, in which the course indications are not given by observing the two reed motions as heretofore, but by means of a zero-center pointer type indicating instrument. The motion of the two reeds generates small alternating voltages, which when rectified by oxide rectifiers and passed in opposing polarities through a zero-center indicating instrument, serve to give course indications by the deflection of the indicating instrument needle in the direction of deviation of the airplane from the course. Each reed converter unit consists of a polarized reed tuned to one of the beacon modulation frequencies. The reed vibrates between a set of driving coils which are supplied with the signal from the radio range, and also extends between a set of pickup coils, and generates a voltage in these coils. Since a null method of course indication is used, it is necessary to provide a signal volume indicator in the form of a 0-500 microammeter in the output circuit of the oxide rectifiers. Several forms of converter selector switch circuit arrangements are shown. The advantages and disadvantages of the reed converter as compared to the tuned reed indicator are discussed.