Sparse phase-stepping in two-dimensional x-ray phase contrast imaging

Kondoh, Takeshi; Date, Takashi; Yamaguchi, K.; Nagai, Kentaro; Sato, Genta; Handa, Soichiro; Den, Tohru; Itoh, Hidenosuke; Nakamura, Takashi

doi:10.1364/ao.53.002602

Cited by 2 publications

(2 citation statements)

References 13 publications

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“…The benefit of radiography is that it produces real time images of the position of the pedicle screws but exposure to radiation can be detrimental to the surgeon’s health[ 6 ]. Moreover, two-dimensional images do not provide adequate spatial accuracy[ 7 ]. CAS provides clear three-dimensional images and has significantly reduced the rate of screw misplacements[ 8 ], but it is expensive to use, occupies a large space, and requires complicated registration and tracking methods[ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Basic Study for Ultrasound-Based Navigation for Pedicle Screw Insertion Using Transmission and Backscattered Methods

Chen

Zhai

et al. 2015

PLoS ONE

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The purpose of this study was to understand the acoustic properties of human vertebral cancellous bone and to study the feasibility of ultrasound-based navigation for posterior pedicle screw fixation in spinal fusion surgery. Fourteen human vertebral specimens were disarticulated from seven un-embalmed cadavers (four males, three females, 73.14 ± 9.87 years, two specimens from each cadaver). Seven specimens were used to measure the transmission, including tests of attenuation and phase velocity, while the other seven specimens were used for backscattered measurements to inspect the depth of penetration and A-Mode signals. Five pairs of unfocused broadband ultrasonic transducers were used for the detection, with center frequencies of 0.5 MHz, 1 MHz, 1.5 MHz, 2.25 MHz, and 3.5 MHz. As a result, good and stable results were documented. With increased frequency, the attenuation increased (P<0.05), stability of the speed of sound improved (P<0.05), and penetration distance decreased (P>0.05). At about 0.6 cm away from the cortical bone, warning signals were easily observed from the backscattered measurements. In conclusion, the ultrasonic system proved to be an effective, moveable, and real-time imaging navigation system. However, how ultrasonic navigation will benefit pedicle screw insertion in spinal surgery needs to be determined. Therefore, ultrasound-guided pedicle screw implantation is theoretically effective and promising.

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Section: Introductionmentioning

confidence: 99%

Basic Study for Ultrasound-Based Navigation for Pedicle Screw Insertion Using Transmission and Backscattered Methods

Chen

Zhai

et al. 2015

PLoS ONE

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“…The phase increments are either precisely controlled (Bruning et al 1974) or determined a posteriori from the images themselves (Miao et al 2013, Wen et al 2013b). A hybrid of phase stepping and single-image analysis can reduce the number of phase steps (Kondoh et al 2014). Phase stepping traditionally involves physically scanning a mirror (Bruning et al 1974), a grating (Momose 1995), the imaging device (Roessl et al 2014) or the sample (Arboleda et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Motionless electromagnetic phase stepping versus mechanical phase stepping in x-ray phase-contrast imaging with a compact source

Harmon¹,

Miao²,

Gomella³

et al. 2015

Phys. Med. Biol.

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X-ray phase contrast imaging based on grating interferometers detects the refractive index distribution of an object without relying on radiation attenuation, thereby having the potential for reduced radiation absorption. These techniques belong to the broader category of optical wavefront measurement, which requires stepping the phase of the interference pattern to obtain a pixel-wise map of the phase distortion of the wavefront. While phase stepping traditionally involves mechanical scanning of a grating or mirror, we developed electromagnetic phase stepping (EPS) for imaging with compact sources to obviate the need for mechanical movement. In EPS a solenoid coil is placed outside the x-ray tube to shift its focal spot with a magnetic field, causing a relative movement between the projection of the sample and the interference pattern in the image. Here we present two embodiments of this method. We verified experimentally that electromagnetic and mechanical phase stepping give the same results and attain the same signal-to-noise ratios under the same radiation dose. We found that the relative changes of interference fringe visibility were within 3.0% when the x-ray focal spot was shifted by up to 1.0 mm in either direction. We conclude that when using x-ray tube sources, EPS is an effective means of phase stepping without the need for mechanical movement.

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Sparse phase-stepping in two-dimensional x-ray phase contrast imaging

Cited by 2 publications

References 13 publications

Basic Study for Ultrasound-Based Navigation for Pedicle Screw Insertion Using Transmission and Backscattered Methods

Basic Study for Ultrasound-Based Navigation for Pedicle Screw Insertion Using Transmission and Backscattered Methods

Motionless electromagnetic phase stepping versus mechanical phase stepping in x-ray phase-contrast imaging with a compact source

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