Biomedical Engineering Reference
In-Depth Information
Fig. 2
Ultra-wideband
emission limit for indoor
systems. [
17
]
−40
−45
−50
−55
−60
−65
−70
Indoor Limit
Part 15 Limit
−75
−80
10
0
10
1
Frequency (GHz)
3. Conventional microwave tomography has computational challenges. Using
space-time UWB imaging, these problems can be solved and a very good
three-dimensional picture of the breast can be obtained.
4. Using space-time UWB imaging systems, a precision of less than 0.5 cm is
expected which is good enough for early detection and localization of breast
cancer.
5. Finally, UWB microwave imaging is able to detect if the lesion is malignant or
benign. For benign lesions, the dielectric properties are not different from normal
tissues as much as they are for malignant lesions. As a result, the scattered waves
are not as strong as they are for malignant tissues.
Ultra-Wideband Technology for Breast Cancer Detection
UWB is a communication technology that can achieve high data rates of up to 1 Gbps,
uses very low power pulses and is suitable for short-distance applications [
15
,
16
].
Due to the use of short pulses which results in high multi-path resolution, UWB
systems do not have problems with fading, which is a serious problem in narrowband
systems. Furthermore, because of the wideband nature of these systems, power is
distributed over a wide range of frequency, which results in a very low power level at
each frequency. Consequently, less interference with other RF systems is expected.
In 2002, the Federal Communication Commission (FCC) authorized commercial
use of the band from 3.1 to 10.6 GHz for research and technology development
of new electronic systems. Although different narrowband radio systems operate
in this range of frequency, as long as UWB systems satisfy FCC's spectral mask,
they can coexist with narrowband systems. For indoor applications, this mask is
shown in Fig.
2
and Fig.
3
. As shown, maximum equivalent isotropic radiated power
(EIRP) spectral density which is allowed by FCC is
41.3 dBm/MHz. This mask
suggests interesting short-distance applications for UWB range. On the other hand,
high spatial resolution of this technology makes it a promising candidate for medical
imaging.
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