A breast tumor is visible by a passive microwave radiometer if it changes the radiometric output of a healthy breast to an extent that overcomes the radiometric resolution for the given sensing antenna and integration time. We modeled breast temperature by the standard Pennes equation using thermal parameters found in the literature for normal and cancerous breast tissue. An apparent thermal volume and its dependence on blood perfusion have been estimated. The radiometric weighting function has been evaluated as a function of the size of a contacting antenna modeled as an aperture antenna. For comparison with the radiometric resolution, the difference signal between the outputs in the presence of a lesion and in its absence has been evaluated for different tumor sizes and depths. The results of the numerical analysis show that this difference signal depends on the average over-temperature in the lesion times the heating efficiency, given by the fraction of power delivered to the tumor when the antenna radiates onto the breast in active modality. A tumor of 6 mm (10 mm) diameter is visible by a 0.1 K radiometer and a 3 cm aperture antenna when it is not deeper than 1.2 cm (2.8 cm) under the assumption of ideal radiometer and antenna.

Among strategies to reduce surgical site infection (SSI) risk, we concentrate on the optimization of the air quality through the heating, ventilation, and air conditioning (HVAC) system. Current ventilation standards applied by some European countries have been compared and show uncertainty in the criteria for dimensioning the HVAC system. The development of a comprehensive regulation needs further discussion.

A breast tumor is visible by a passive microwave radiometer if it changes the radiometer output of a healthy breast to an extent that overcomes the radiometric resolution. The characteristics of a new dual-band near-field radiometer are exposed. The deformation by an antenna pressed against the breast lowers the distance of a subsurface tumor from the contacted surface improving the tumor radiometric visibility. We show this result by modeling breast deformation, temperature and corresponding radiometer output both in the presence of a tumor and in its absence. For a 25% net breast deformation, a tumor of 10mm diameter is visible by a 0.1°C radiometer and a 3cm aperture antenna when it is 4 cm deep in the undeformed breast.

In microwave radiometry for early detection of breast malignancy a contacting antenna is scanned on the breast surface, while a pressure is exercised along with a deformation. Assuming the antenna at lower temperature than the breast, the results of a numerical modeling show an interesting increase in tumor radiometric visibility.

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