Laser optoacoustic imaging of breast cancer in vivo

Abstract

A clinical prototype of the laser optoacoustic imaging system (LOIS) was employed for breast cancer detection and localization in patients with confirmed breast cancer and scheduled for radical mastectomy. The prototype LOIS used a single optical fiber for delivery of laser pulses, an arc shaped 32-element PVDF transducer array for ultrawide-band piezoelectric detection of optoacoustic signals and a single-channel data acquisition card for signal processing. The resonance ultrasound frequency of the 1 10 im PVDF film was outside detectable range of ultrasound. Spatial resolution of the transducer array was slightly better than 1mm in radial direction and slightly worse than 1 mm in lateral direction. The system was optimized for contrast and sensitivity. Data acquisition, signal conditioning and image processing were significantly improved and optimized resulting in reduced image frame rate of 2 seconds employing 700 MHz Aphion processor. The computer code for digital signal processing employed band-pass hyper-Gaussian filtering and denoising. An automatic recognition of the optoacoustic signal detected from the irradiated surface was implemented in order to visualize the breast surface and improve the accuracy of tumor localization. Radial back-projection algorithm was employed adopting combination of integration along spherical wavefronts and integration along planar wavefronts (as in Radon transform) for image reconstruction. The system performance was evaluated initially in breast tissue-like phantoms with embedded blood vessels. Clinical studies in breast cancer patients scheduled for surgical mastectomy were performed and compared with xray radiography, ultrasound and pathology reports.

Optical clearing of biological tissues: prospects of application in medical diagnostics and phototherapy

“…Detection of the acoustic waves is the base of the optoacoustic (or photoacoustic) methods [1,3]. The main applications of the photoacoustic (PA) method are in the field of visualisation of strongly absorbing objects, such as blood vessels [263][264][265] and tumours [266]. This method can be also used for imaging of subcutaneous structures [267] and measuring the blood oxygenation [268].…”

Synthesis and Evaluation of Near-Infrared (NIR) Dye−Herceptin Conjugates as Photoacoustic Computed Tomography (PCT) Probes for HER2 Expression in Breast Cancer

“…Recently, there has been a growing interest in photoacoustic computed tomography (PCT) imaging (1)(2)(3)(4)(5)(6)(7)(8). It is a noninvasive imaging modality capable for obtaining both structural and functional information in biological tissues.…”

“…By labeling Herceptin with several NIR-dye molecules, a large NIR absorption may be achieved with less fluorescence. Thus, we hypothesized that NIR-dye labeled Herceptin would be a suitable probe to detect breast cancer by PCT 7 . Herein we report the preparation and evaluation of Herceptin-dye conjugates with a broad range of DOLs as PCT probes for HER2 expressing breast cancer.…”

Wideband focused transducer array for optoacoustic tomography

“…Low resolution in that direction was the main reason of the decreased quality in the design of all transducer arrays described before [3]. This problem can be solved by using an array of focused transducers [4,5,6]. The focused transducer sensitivity is distributed in a narrow focal region.…”