Abstract: A traceable surgical tool is positioned, monitored and displayed in real-time directly with pre-scanned three dimensional CT/MRI slices of a patient. The tool positioning and inclination is obtained by real time combined ultrasound (US)/RF transmissions between at least four transmitting units (TUs) and a mobile unit (MU) attached to or included in the tool. No more than three of the TUs may be coplanar. In some embodiments, at least one TU includes two US transmitters transmitting at different frequencies. Image space coordinates of the CT/MRI scanned patient are mapped by a one-to- one transformation onto real space coordinates of the patient undergoing a surgical procedure. The mapping is aided by, in the real space environment, touching once each of at least three markers fixedly attached to the patient and pre-scanned with the patient in the image space.

Abstract: A traceable surgical tool is positioned, monitored and displayed in real-time directly with pre-scanned three dimensional CT/MRI slices of a patient. The tool positioning and inclination is obtained by real time combined ultrasound (US)/RF transmissions between at least four transmitting units (TUs) and a mobile unit (MU) attached to or included in the tool. No more than three of the TUs may be coplanar. In some embodiments, at least one TU includes two US transmitters transmitting at different frequencies. Image space coordinates of the CT/MRI scanned patient are mapped by a one-to- one transformation onto real space coordinates of the patient undergoing a surgical procedure. The mapping is aided by, in the real space environment, touching once each of at least three markers fixedly attached to the patient and pre-scanned with the patient in the image space.

Abstract: A method for measuring liquid content of a porous medium such as soil applies a voltage to a plurality of point contacts placed in the porous medium to be measured for liquid content, as well as to a common electrode also inserted into the porous medium to be measured in spaced relation to the point contacts. Liquid content in the soil is determined as a function of the number of the point contacts having electrical continuity with the common electrode through the porous medium to be measured for liquid content. A predetermined electrical resistance is inserted between each of the point contacts and a source of the voltage applied to the point contacts.