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 $800\mathrm{nm}$ 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 $1{\mathrm{cm}}^3$ model tumor to be valid to a depth of $5\mathrm{cm}$ .