A medical device for operation by a physician user, in a patient's lung tissue having a suspected tumor, the medical device comprising: a) a catheter having an elongate catheter body terminating in a proximal handle and extending along an axis to a distal tip , said elongate catheter body adapted for delivery to lung tissue by insertion through a percutaneous needle ; b) a plurality of electromagnetic sensing coils , located within said distal tip ; c) at least one electromagnetic sensing coil in said proximal handle ; said sensing coils operating together to permit navigation through lung tissue and for reporting the location of said catheter distal tip in said lung tissue; d) a cylindrical ultrasound transducer array located within said distal tip for transmitting and receiving ultrasonic energy, wherein said medical device is configured to operate the cylindrical ultrasound transducer array in a first imaging mode to acquire an image of a first target area located in a first target plane and to define a second target area located in said first target plane comprising a reduced second target area smaller than said first target area and further to operate the cylindrical ultrasound transducer array in a second backscatter mode to evaluate the spectral characteristics of acoustic energy reflected from said second target area forming a quantitative ultrasound (QUS) data set, wherein the cylindrical ultrasound transducer array is operable at 20MHz in the first imaging mode and at a different frequency higher than 20MHz in the second backscatter mode, the medical device further comprising: e) a navigation system/ultrasound display to present navigation, location and ultrasound data to said physician user. a) a catheter having an elongate catheter body terminating in a proximal handle and extending along an axis to a distal tip , said elongate catheter body adapted for delivery to lung tissue by insertion through a percutaneous needle ; b) a plurality of electromagnetic sensing coils , located within said distal tip ; c) at least one electromagnetic sensing coil in said proximal handle ; said sensing coils operating together to permit navigation through lung tissue and for reporting the location of said catheter distal tip in said lung tissue; d) a cylindrical ultrasound transducer array located within said distal tip for transmitting and receiving ultrasonic energy, wherein said medical device is configured to operate the cylindrical ultrasound transducer array in a first imaging mode to acquire an image of a first target area located in a first target plane and to define a second target area located in said first target plane comprising a reduced second target area smaller than said first target area and further to operate the cylindrical ultrasound transducer array in a second backscatter mode to evaluate the spectral characteristics of acoustic energy reflected from said second target area forming a quantitative ultrasound (QUS) data set, wherein the cylindrical ultrasound transducer array is operable at 20MHz in the first imaging mode and at a different frequency higher than 20MHz in the second backscatter mode, the medical device further comprising: e) a navigation system/ultrasound display to present navigation, location and ultrasound data to said physician user. <EOS>