Development of a tendon driven robotic probe for prostate palpation

Abstract

Palpation is a clinical diagnosis method utilized by physicians to acquire valuable information about the pathological condition of an organ using the sense of touch. This method, however, is subjective. The accuracy depends on the physician's experience and skill. Therefore, to make palpation objective and minimize variability in prostate cancer diagnosis among physicians, an automated palpation system is required. This paper describes the design and experimental evaluation of a 2 Degrees of Freedom (2DoF) tendon driven robotic palpation probe. The probe's palpation motion is controlled by actuating driving tendons using a cable-differential pulley transmission system and a return spring. A kinematic model of the robotic probe was derived. Furthermore, a tendon path length model was geometrically determined, and an optimization method for guide arc center placement to minimize change in tendon length was presented. Preliminary experimental and theoretical results were compared to determine the positioning accuracy. The difference between theoretical pitch angles [0 o ,80 o ] and measured values for the yaw angle range of [0 o , 40 o ] was found to be in the range of 0.03 o ~ 5.06 o .Clinical Relevance-Diagnosis based on manual palpation is often subjective and palpation sensitivity depends on the physician's level of experience and skill . Therefore, an objective method for acquiring tactile information is relevant. Robotic palpation system provides objective and quantitative information for better understanding of the pathological and physiological changes in the tissue using mechanical properties as biomarkers.

A cable driven robotic palpation system with contact force sensing based on cable tension observation

“…The wrist also features non movable guide arcs on the yaw part of the wrist to prevent acute bending of the cables when the probe yaws. 19 This ensures durability of the cables, simpler construction of the probe with few moving parts. The probe's dimensions were set to 14 mm outer diameter and 135 mm length.…”

“…The returning wire cable is fixed between the joint pulley and the return spring. The wrist also features non movable guide arcs on the yaw part of the wrist to prevent acute bending of the cables when the probe yaws 19 . This ensures durability of the cables, simpler construction of the probe with few moving parts.…”

Application of the shear wave elastography in the assessment of carotid body tumors: A preliminary study

“…Elasticity is the tendency of tissue to resist deformation with an applied force, or to resume its original shape after removal of the force (4). Manual palpation is a clinical diagnosis method utilized by physicians to acquire elasticity information of an organ using the sense of touch (5). It can be used to check whether there is a mass in lateral neck and evaluate its elasticity.…”