Palpation force modulation strategies to identify hard regions in soft tissue organs

Abstract

This paper presents experimental evidence for the existence of a set of unique force modulation strategies during manual soft tissue palpation to locate hard abnormalities such as tumors. We explore the active probing strategies of defined local areas and outline the role of force control. In addition, we investigate whether the applied force depends on the non-homogeneity of the soft tissue. Experimental results on manual palpation of soft silicone phantoms show that humans have a well defined force control pattern of probing that is used independently of the non-homogeneity of the soft tissue. We observed that the modulations of lateral forces are distributed around the mean frequency of 22.3 Hz. Furthermore, we found that the applied normal pressure during probing can be modeled using a second order reactive autoregressive model. These mathematical abstractions were implemented and validated for the autonomous palpation for different stiffness parameters using a robotic probe with a rigid spherical indentation tip. The results show that the autonomous robotic palpation strategy abstracted from human demonstrations is capable of not only detecting the embedded nodules, but also enhancing the stiffness perception compared to static indentation of the probe.

Haptic feedback in the da Vinci Research Kit (dVRK): A user study based on grasping, palpation, and incision tasks

“…Differently, haptic force reflection made a statistically significant difference for palpation, both in terms of inclusion detection rate and inspection time. Incidentally, the recorded indentation forces were consistent with previous studies . Moreover and more importantly, it resulted that users took a longer time to palpate when provided with haptic feedback, yet they were able to detect more hard nodules.…”

“…Incidentally, the recorded indentation forces were consistent with previous studies. 44 Moreover and more importantly, it resulted that users took a longer time to palpate when provided with haptic feedback, yet they were able to detect more hard nodules. Similarly, haptic feedback also significantly reduced tissue damage rate during incision.…”

Design of a Wearable Fingertip Haptic Device for Remote Palpation: Characterisation and Interface with a Virtual Environment

“…The range of normal forces in the "robust" conditions had a mean of 3.7 N (SD of 2.3), which is comparable to the 3.2 N mean of normal forces measured when participants palpated tissue using their index finger directly as reported by Konstantinova et al (2017). The measured forces (of Table 2) are an estimate, as the precise magnitude depends on the thickness of the user's fingertip.…”

Visual and tactile feedback for a direct‐manipulating tactile sensor in laparoscopic palpation

“…Many research groups have tried to achieve intraoperative tumor detection in minimally invasive surgery such as laparoscopic surgery. For instance, automated palpation systems have been developed with Gaussian process adaptive sampling, a force modulation strategy abstracted from human manual palpation, machine learning algorithms and simultaneous estimation of stiffness distribution and registration . Although automated palpation can achieve high accuracy and repeatability, the control scheme might be extremely difficult in a surgical situation.…”

“…The sensory feedback for tumor detection also affects the movement in manipulation. In manual palpation, humans use complex modulation strategies of contact force and scanning speed . These studies imply that humans change their motor control appropriately according to the sensory information and the current sensing environment.…”