Improving the Use of Vibro-Acoustography forBrachytherapy Metal Seed Imaging:A Feasibility Study

Mitri, F.G.; Trompette, P.; Chapelon, Jean‐Yves

doi:10.1109/tmi.2003.819934

Cited by 71 publications

(45 citation statements)

References 19 publications

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“…In the medical field, VA has been successfully used for imaging small particles such as calcium deposits on heart valve leaflets [15], microcalcifications in breast tissue [16][17][18][19], calcifications in arteries [11,20], excised human cancerous liver tissue [21], and standard brachytherapy seeds in gel phantoms [22].…”

Section: Introductionmentioning

confidence: 99%

In vitro comparative study of vibro-acoustography versus pulse-echo ultrasound in imaging permanent prostate brachytherapy seeds

2009

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Background-Permanent prostate brachytherapy (PPB) is a common treatment for early stage prostate cancer. While the modern approach using trans-rectal ultrasound guidance has demonstrated excellent outcome, the efficacy of PPB depends on achieving complete radiation dose coverage of the prostate by obtaining a proper radiation source (seed) distribution. Currently, brachytherapy seed placement is guided by trans-rectal ultrasound imaging and fluoroscopy. A significant percentage of seeds are not detected by trans-rectal ultrasound because certain seed orientations are invisible making accurate intra-operative feedback of radiation dosimetry very difficult, if not impossible. Therefore, intra-operative correction of suboptimal seed distributions cannot easily be done with current methods. Vibro-acoustography (VA) is an imaging modality that is capable of imaging solids at any orientation, and the resulting images are speckle free.Objective and methods-The purpose of this study is to compare the capabilities of VA and pulse-echo ultrasound in imaging PPB seeds at various angles and show the sensitivity of detection to seed orientation. In the VA experiment, two intersecting ultrasound beams driven at f 1 = 3.00 MHz and f 2 = 3.020 MHz respectively were focused on the seeds attached to a latex membrane while the amplitude of the acoustic emission produced at the difference frequency 20 kHz was detected by a low frequency hydrophone.Results-Finite element simulations and results of experiments conducted under well-controlled conditions in a water tank on a series of seeds indicate that the seeds can be detected at any orientation with VA, whereas pulse-echo ultrasound is very sensitive to the seed orientation.Conclusion-It is concluded that vibro-acoustography is superior to pulse-echo ultrasound for detection of PPB seeds.

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Section: Introductionmentioning

confidence: 99%

In vitro comparative study of vibro-acoustography versus pulse-echo ultrasound in imaging permanent prostate brachytherapy seeds

2009

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“…Each pixel on the observation plane corresponds to the contribution (sum) of the acoustic response of all elements on the source plane. The acoustic responses for frequencies f 1 and f 2 are given by (10) where A mn is an apodization term to define the different apertures for ω 1 and ω 2 which represents the assignment of channel considering time delay and frequency of excitation (k = 1,2), and p mn is the contribution of pressure of each element in the source plane at mncoordinate. A mn is 1 when an element is assigned ω and 0 otherwise.…”

Section: Numeric Implementation For the Acoustic Field Analysismentioning

confidence: 99%

“…These problems can be partially solved by using a water tank to host the transducer. Multiple laboratory VA studies using the confocal transducer in a water tank have been performed in breast [7] [8], thyroid [9], and prostrate tissues [10] [11] [12] [13]. The same confocal transducer has been also used for in vivo measurements in human breast [14] [15] [16].…”

Section: Introductionmentioning

confidence: 99%

Vibro-acoustography beam formation with reconfigurable arrays

Urban¹,

Kamimura

Carneiro

et al. 2011

The Journal of the Acoustical Society of America

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In this work, we present a numerical study of the use of reconfigurable arrays (RCA) for vibroacoustography (VA) beam formation. A parametric study of the aperture selection, number of channels, number of elements, focal distance, and steering parameters is presented in order to show the feasibility and evaluate the performance of VA imaging based on RCA. The transducer aperture was based on two concentric arrays driven by two continuous-wave or toneburst signals at slightly different frequencies. The mathematical model considers a homogeneous, isotropic, inviscid medium. The point-spread function of the system is calculated based on angular spectrum methods using the Fresnel approximation for rectangular sources. Simulations considering arrays with 50 × 50 to 200 × 200 elements with number of channels varying in the range of 32 to 128 are evaluated to identify the best configuration for VA. Advantages of two dimensional and RCA arrays and aspects related to clinical importance of the RCA implementation in VA such as spatial resolution, image frame-rate, and commercial machine implementation are discussed. It is concluded that RCA transducers can produce spatial resolution similar to confocal transducers, steering is possible in elevation and azimuthal planes, and optimal settings for number of elements, number of channels, maximum steering, and focal distance are suggested for VA clinical application. Furthermore, an optimization for beam steering based on the channel assignment is proposed for balancing the contribution of the two waves in the steered focus.This work was done while the first author was at Mayo Clinic as a visiting graduate student.Disclosure of financial interest: Mayo Clinic and one of the authors (MF) have a financial interest associated with the technology used in this research; the technology has been licensed in part for some specific application areas to industry. NIH Public Access

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“…TRUS provides sufficient soft tissue contrast to delineate the prostate boundaries. However, despite significant efforts in seed localization from ultrasound, [12][13][14][15][16][17][18] robust seed segmentation in ultrasound is not yet possible. It was shown that up to 25% of the seeds can be missed even through manual segmentation of B-mode images.…”

Section: Introductionmentioning

confidence: 99%

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis

et al. 2011

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Purpose: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. Methods: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. Results: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86 6 0.44 mm (Mean 6 STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5 6 0.4 mm. Conclusions: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use.

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Improving the Use of Vibro-Acoustography forBrachytherapy Metal Seed Imaging:A Feasibility Study

Cited by 71 publications

References 19 publications

In vitro comparative study of vibro-acoustography versus pulse-echo ultrasound in imaging permanent prostate brachytherapy seeds

In vitro comparative study of vibro-acoustography versus pulse-echo ultrasound in imaging permanent prostate brachytherapy seeds

Vibro-acoustography beam formation with reconfigurable arrays

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis

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