Abstract
Eight retired breeder rats were acquired that had developed spontaneous mammary tumors. Tumors were diagnosed microscopically as mammary gland fibroadenomas. Two-dimensional gray-scale B-mode images of the tumors in the rats were constructed from backscattered echoes using an 8 MHz (90% bandwidth) single element ultrasonic transducer. From the gray-scale B-mode images, regions-of-interest (ROIs) were selected in the tumors and surrounding tissues. The power spectra of backscattered RF echoes gated from the ROIs were used to estimate the average scatterer diameters and concentrations. A unique estimation scheme was used to obtain the average scatterer diameters and concentrations. The average scatterer diameter was related to the slope of the best-fit line to the reduced measured power spectrum versus the frequency squared. The scatterer concentration was determined from the intercept of the best-fit line. The reduced measured power spectrum is the measured power spectrum minus 40 log of the frequency. Parametric B-mode images were constructed by converting ROI boxes into colored pixels. The color of the pixels was related to the estimated scatterer properties. The images showed a distinct difference between the tumor and surrounding healthy tissues. Scatterer sizes inside the tumor were on average 30% larger than scatterer sizes in surrounding normal tissues.
Original language | English (US) |
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Pages (from-to) | 152-159 |
Number of pages | 8 |
Journal | Proceedings of SPIE-The International Society for Optical Engineering |
Volume | 4687 |
DOIs | |
State | Published - 2002 |
Keywords
- Backscatter
- Parametric imaging
- RF-based imaging
- Tissue characterization
- Ultrasound
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering