Acoustic imaging of thick biological tissue

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2009-07, Vol.56 (7), p.1352-1358
• Main Authors: Maeva, E., Severin, F., Miyasaka, C., Tittmann, B.R., Maev, R.G.
• Format: Article
• Language: English
• Subjects: Acoustic imaging; Acoustic microscopes; Acoustic reflection; Acoustic signal processing; Acoustical measurements and instrumentation; Acoustics; Biological; Biological and medical sciences; Biological tissues; Breast; Breast - ultrastructure; Breast cancer; Breast Neoplasms - ultrastructure; Cancer; Cellular structure; Diagnostic Imaging - methods; Exact sciences and technology; Female; Frequency; Fundamental areas of phenomenology (including applications); Histological Techniques; Humans; Imaging; Intestine, Small - ultrastructure; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Microscopy, Acoustic - methods; Miscellaneous. Technology; Optical attenuators; Optical imaging; Optical microscopy; Optical reflection; Physics; Reflection; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic technology
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2009.1191

Up to now, biomedical imaging with ultrasound for observing a cellular tissue structure has been limited to very thinly sliced tissue at very high ultrasonic frequencies, i.e., 1 GHz. In this paper, we present the results of a systematic study to use a 150 to 200 MHz frequency range for thickly sliced biological tissue. A mechanical scanning reflection acoustic microscope (SAM) was used for obtaining horizontal cross-sectional images (C-scans) showing cellular structures. In the study, sectioned specimens of human breast cancer and tissues from the small intestine were prepared and examined. Some accessories for biomedical application were integrated into our SAM (Sonix HS-1000 and Olympus UH-3), which operated in pulse-wave and tone-burst wave modes, respectively. We found that the frequency 100 to 200 MHz provides optimal balance between resolution and penetration depth for examining the thickly sliced specimens. The images obtained with the lens focused at different depths revealed cellular structures whose morphology was very similar to that seen in the thinly sectioned specimens with optical and scanning acoustic microscopy. The SAM operation in the pulse-echo mode permits the imaging of tissue structure at the surface, and it also opens up the potential for attenuation imaging representing reflection from the substrate behind the thick specimen. We present such images of breast cancer proving the method's applicability to overall tumor detection. SAM with a high-frequency tone-burst ultrasonic wave reveals details of tissue structure, and both methods may serve as additional diagnostic tools in a hospital environment.