Breast cancer is the most common cancer in women worldwide. Two million women are diagnosed annually, resulting in 685,000 annual deaths. Early diagnosis is critical to reducing mortality. Although screening with mammography has been shown to have reduced breast cancer-related mortality through early detection, dense breast tissues reduce mammographic sensitivity, potentially delaying diagnoses, and contributing to poorer outcomes. Therefore, there is a need for more accessible and cost-effective supplemental screening technologies, especially for high-risk populations, especially women with dense breasts. To address these challenges, a promising approach involves combining widely available, cost-effective, and accessible ultrasound-based technologies with economical hardware, software modules, and automated techniques. Among these technologies, Doppler imaging plays a crucial role in the clinical evaluation of breast abnormalities, as intratumoural blood flow has been shown to correlate with the aggressiveness and histological grade of the tumour. The development of a novel automated, portable, and a patient-dedicated 3D automated breast ultrasound (ABUS) system for point-of-care breast cancer supplemental screening holds significant promise. The proposed system has previously demonstrated the capability to generate accurate whole-breast B-mode images, which can aid in the early detection of breast cancer in women with dense breasts. Additionally, it offers the advantage of incorporating Doppler imaging for the assessment of blood flow within suspicious lesions, a capability not commonly available with commercial ABUS systems. By leveraging Doppler imaging in conjunction with 3D Bmode ABUS, this innovative approach could improve breast cancer-related health outcomes and equity in access to healthcare, especially for underserved and vulnerable populations.
High dose-rate brachytherapy is a typical part of the treatment process for cervical cancer. During this procedure, radioactive sources are placed locally to the malignancy using specialized applicators or interstitial needles. To ensure accurate dose delivery and positive patient outcomes, medical imaging is utilized intra-procedurally to ensure precise placement of the applicator. Previously, the fusion of three-dimensional ultrasound images has been investigated as an alternative volumetric imaging technique during cervical brachytherapy treatments. However, the need to manually register the two three-dimensional ultrasound images offline resulted in excessively large registration errors. To overcome this limitation, we have designed and developed a tracked, automated mechatronic system to inherently register three-dimensional ultrasound images in real-time. We perform a system calibration using an external coordinate system transform and validate the system tracking using a commercial optical tracker. The results of both experiments indicated sub-millimeter system accuracy, indicating the superior performance of our device. Future work for this study includes performing phantom validation experiments and translating our device into clinical work.
KEYWORDS: Image resolution, 3D image processing, 3D acquisition, Breast, Spatial resolution, Voxels, Ultrasonography, Image fusion, Image acquisition, Breast cancer
With increasing evidence for supplemental ultrasound (US) for breast cancer screening in women with dense breasts, there is an interest in developing more robust and cost-effective techniques. Compared with handheld US, automated breast ultrasound (ABUS) shows improvements in detection, reproducibility, and operator dependence. However, limitations exist as high-quality image acquisition is still reliant on operator training and patient positioning. Moreover, installation of current commercial systems is expensive, and they lack point-of-care capabilities, limiting their bedside utility. We developed a dedicated three-dimensional (3D) ABUS device that contains a wearable patient-conforming 3D-printed dam, compression assembly, and motorized 3DUS scanner. Acquisition involves acquiring 2DUS images at a fixed spatial interval and reconstructing them into a 3DUS image. While the 3DUS image has a high in-plane resolution, its out-ofplane (elevational) US resolution in the reconstruction plane is poor. We hypothesize that combining orthogonal images can improve 3DUS image resolution by recovering some out-of-plane resolution. With orthogonal 3DUS images occupying the same volume, the intensity at any 3D voxel coordinate can be computed from a spherical-weighted function of the voxel intensities from the two original 3DUS images. In this paper, we describe the dedicated 3D ABUS device, its orthogonal acquisition, and the combination approach for creating a 3D complementary breast ultrasound (CBUS) image. We perform experiments to evaluate their impact on 3D image resolution. The proposed CBUS method was evaluated with orthogonally acquired craniocaudal and mediolateral 3DUS images of an angular wire phantom, then calculating the full width at half maximum (FWHM) of the line spread function for each wire. Our results show that 3D CBUS images with orthogonal 3DUS images improves resolution uniformity by recovering some out-of-plane resolution.
High dose rate brachytherapy is a common procedure used in the treatment of gynecological cancers to irradiate malignant tumors while sparing the surrounding healthy tissue. While treatment may be delivered using a variety of applicator types, a hybrid technique consisting of an intracavitary applicator and interstitial needles allows for highly localized placement of the radioactive sources. To ensure an accurate and precise procedure, identification of the applicator and needle tips is necessary. The use of three-dimensional (3D) transrectal ultrasound (TRUS) and transabdominal ultrasound (TAUS) imaging has been previously investigated for the visualization of the intracavitary applicators. However, due to image artifacts from the applicator, needle tip identification is severely restricted when using a single 3D US view. To overcome this limitation and improve treatment outcome, we propose the use of image fusion to combine TRUS and TAUS images for the complete visualization of the applicator, needle tips, and surrounding anatomy. In this proof-of-concept work, we use a multimodality anthropomorphic pelvic phantom to assess the feasibility of image fusion and needle visualization using a hybrid brachytherapy applicator. We found that fused 3D US images resulted in accurate visualization of the pertinent structures when compared with magnetic resonance images. The results of this study demonstrate the future potential of image fusion in gynecological brachytherapy applications to ensure high treatment quality and reduce radiation dose to surrounding healthy tissue. This work is currently being expanded to other applicator types and is being applied to patients in a clinical trial.
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