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The sense of touch is a valuable tool for surgeons in open procedures to directly access buried structures and organs, identify their margins, and prevent undesired cuts. Furthermore, as tumors manifest as stiffer than healthy tissues, surgeons rely on touch sensation for their detection. Modern surgical procedures are performed in a minimally invasive way; however, despite the many benefits for patients, it hinders the surgeon's ability to directly interact and manipulate the tissue. Therefore, restoring the sense of touch in Minimally Invasive Surgery (MIS) has been an active research topic, with many novel devices developed by the research community for creating stiffness distribution maps of underlying tissues. We developed in our previous work a Wireless Palpation Probe (WPP) to restore tissue palpation in MIS by creating a real-time stiffness distribution map of the palpated tissue. The WPP takes advantage of a field-based magnetic localization algorithm to measure its position, orientation, and tissue indentation depth in addition to a barometric sensor to measure the indentation tissue pressure. Similarly to other pressure sensors covered by silicone rubber, the deformations of both the tissue and silicone material introduce nonlinearities which detrimentally affect the sensor measurements. In this work, we characterized and calibrated different diameter WPP heads with a new design that allows exchangeability and disposability of the probe head. The benchtop trials showed that this method can effectively reduce the error in the sensor pressure measurements to 5 \% with respect to the reference sensor. This method can be extended to any mechanical tumor probing system where silicone rubber is interposed between the target tissue and the sensing element. Furthermore, we studied the effect of the head diameter on the device spatial resolution to detect different size tumor simulators embedded into different stiffness silicone phantoms. Overall, the results showed a tumor detection rate over 90 %, independent of the head diameter, when an indentation depth of at 5 mm is applied on the tissue simulator. All authors have seen the manuscript and agree to its submission to Sensors and Actuator A: physical. Sincerely, Marco Beccani ----------------------------------------------------------------------- *Manuscript(includes changes marked in red font for revision documents) Click here to view linked ReferencesThe benchtop trials showed that this method can effectively reduce the error in the sensor pressure measurements to 5% with respect to the reference sensor.This method can be extended to any mechanical tumor probing system where silicone rubber is interposed between the target tissue and the sensing element.Furthermore, we studied the effect of the head diameter on the device spatial resolution to detect different size tumor simulators embedded into different stiffness silicone phantoms. Overall, the results showed a tumor detection rate over 90 %, independent of the head diameter, when an indenta...

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