Simple ac circuit for breast cancer detection and object detection

The detection of subsurface objects by near infrared (NIR) spectroscopy and imaging has usually been done with a large number of source positions and a corresponding large number of detector positions. Significant signals have been obtained with a multitude of sources and detectors, to be exact, 4 multiwavelength light emitting diodes (LEDs) and 16 nearby detectors photodiode silicon diode detectors. A great simplification is made by a dedicated device in which two out of phase sources and a single detector, used in a differential circuit, enable sensitive detection of the appearance of a functionally induced inhomogeneity, for example, a breast cancer or a brain functional signal. By using two LED NIR sources in antiphase at a wavelength appropriate to blood volume increment for the in detection of breast cancer angiogenesis, it is possible to design and construct a very efficient handheld scanner which will indicate the presence of a subsurface angiogenesis by creating imbalance of the optical patterns of the two 800 nm LED sources. Localization and an estimate of the size of the subsurface object may be obtained by scanning the device serially across the breast, as shown in a dynamic 1 cm(3) model tumor to be valid to a depth of 5 cm. (c) 2006 American Institute of Physics.