Development of a palpation sensor for detection of prostatic cancer and hypertrophy (optimum structural design of sensor)

This paper is concerned with the development of a soft palpation sensor for detection of prostatic cancer and hypertrophy. The sensor is a layered medium with two polyvinylidene fluoride (PVDF) films embedded in the matrix sponge rubber. It is pressed against the prostates and the output voltage signals from the polymer films are measured. The temporal mean values, I1 and I2, of absolute voltage signals from the films are calculated and their ratioI1=I2 is used as the sensor output. First, the fundamental characteristics of a rectangular sensor with a plane surface are examined. Then, the surface geometry of the sensor was designed so that it clearly indicates the nature on the stiffness of the soft material. Finally, a compact cylindrical sensor attached to the doctor's forefinger is described and experimental studies of its performance as a palpation sensor are presented. Some representative clinical data on the normal and hardened prostate glands are also presented.