Advanced Diagnostics, Inc. (ADI) has developed a technique using Diffractive Energy Imaging (DEI) to provide an accurate, non-ionizing method for continuously tracking biopsy needles. The method utilizes ultrasound to generate large field-of-view, high resolution, multi-planar images. Accurate, real-time biopsy guidance using DEI is possible by identifying the physical relationship between a lesion and a focal plane or image slice. The lesion is located by progressively focusing through the breast volume until the lesion is visualized with enough clarity to distinguish it from surrounding tissue. The selected focal plane identifies the lesion location along a medial-lateral axis through the breast. This plane is identified for the physician using a laser pointer to "paint" a line on the skin surface. Cartesian coordinates applied to the image slice define a location for surgical incision and needle entry along this focal plane. Maintaining the needle within the defined focal plane and tracking the needle in real-time on a high-resolution monitor ensures a direct line approach through the tissue to the targeted lesion. Data indicate that physicians experienced in biopsy but without prior DEI operational experience are successful in acquiring simulated targets embedded in biopsy phantoms.
Keywords: biopsy guidance, Diffractive Energy Imaging, acoustic holography, real-time biopsy
Core needle breast biopsies are routinely performed using stereotactic mammography or free-hand reflective ultrasound guidance. Percutaneous core needle biopsies performed using stereotactic mammography guidance are typically lower in cost than excisional biopsies and result in less emotional trauma and physical scarring in patients.1,2,3 The procedure, however, is time consuming and needle accuracy can be compromised with patient movement when real-time image guidance is not available. In addition, stereotactic breast biopsy devices are dedicated systems requiring significant hospital space. In free-hand ultrasound guidance, biopsy accuracy is highly dependent on operator experience and skill. Using this technique, the breast must be stabilized, the needle is maintained parallel to the imaging plane, and position confirmation is made viewing orthogonal planes.4 Advanced Diagnostics, Inc. (ADI) has succeeded in developing an approach to core needle biopsy that utilizes Diffractive Energy Imaging (DEI)5,6 and addresses many of the problems associated with traditional techniques.
DEI is an imaging technology based upon sound and sound wave mechanics, but utilizing sound in a non-traditional fashion. While conventional ultrasound relies on the reflective properties of sound and is a pulsed wave technique, DEI uses a "through wave" technique that takes advantage of the diffractive properties of sound. The DEI image is formed by passing a coherent wave of sound through an object (Figure 1). The ultrasonic energy is absorbed, reflected, diffracted and refracted by anatomical structures, thus perturbing the transmitted wave in a manner unique to the internal anatomy. The summation of these perturbations in the transmitted wave is combined with an unperturbed reference wave in real- time to generate an acoustic hologram. A coherent light source is used to illuminate the hologram. Two-dimensional real-time digital images are then acquired using a high resolution CCD. Image slices acquired in sequence through an
a http://www.goadi.com; phone 1509 375-4029; Advanced Diagnostic, Inc., 2400 Stevens Drive, Suite C, Richland, WA 99352; bphone 1 425 222-7169; Advanced Diagnostics, Inc., I-90 Business Park Bldg #2, 8112 Suite B, 304th Avenue SE, Preston, WA 98050.