Prediction Control for Brachytherapy Robotic System

In contemporary brachytherapy procedure, needle placement at desired location is challenging due to a variety of reasons. We have designed and fabricated an image-guided robot-assisted brachytherapy system to improve the needle placement and seed delivery. In this article we have used two different predictive control strategies in order to investigate the needle insertion efficacy and system dynamics during prostate brachytherapy. First, we used neural network predictive control (NNPC) to predict an insertion force. The NNPC uses the linearized state-space model of the robotic system to predict future system performances. Second, we used feedforward model predictive control (MPC) which allows the controller to compensate the influence of a measured disturbance's impact immediately rather than waiting until the effect appears in the system. Feedback control problem for the contact force regulation is considered. The simulation results and experiments for both cases are presented and compared

A pilot study examining the prognostic utility of tumor shrinkage on cone-beam computed tomography (CBCT) for stage III locally advanced non-small cell lung cancer patients treated with definitive chemoradiation

There has been growing interest in utilizing information from cone-beam computed tomography (CBCT) to help guide both treatment delivery and prognosis. In this assessment of locally advanced unresectable stage III non-small cell lung cancer (NSCLC) treated with definitive chemoradiation, we aimed to determine the survival advantage associated with using CBCT to measure tumor regression. Patient, tumor, and treatment characteristics were collected. The serial tumor shrinkage for each patient was determined from tumor volume contours on weekly CBCTs. Survival analysis was performed using the Kaplan-Meier technique and a Cox proportional hazards model. At least two-thirds of patients had a tumor volume reduction of at least 5% after each week of chemoradiation. A weekly reduction in tumor volume of 5% or greater seen on the CBCT images during radiation therapy was significantly associated with improved overall survival, which remained significant when adjusted for age, histology, grade, and T- and N-stages

Robot Assisted Real-time Tumor Manipulation for Breast Biopsy

Abstract—Breast biopsy guided by imaging techniques such as ultrasound is widely used to evaluate suspicious masses within the breast. The current procedure allows the physician to determine the location and extent of a tumor in the patient breast before inserting the needle. However, there are several problems with this procedure: the complex interaction dynamics between the needle force and the breast tissue will likely displace the tumor from its original position necessitating multiple insertions, causing surgeons ’ fatigue, patient’s discomfort, and compromising the integrity of the tissue specimen. In this work, we present a new concept for real-time manipulation of a tumor using a robotic controller that monitors the image of the tumor to generate appropriate external force to position the tumor at a desired location. The idea here is to demonstrate that it is possible to manipulate a tumor in real-time by applying controlled external force in an automated way such that the tumor does not deviate from the path of the needle. A laboratory experiment has been presented on a phantom that demonstrates the essence of this concept. The success of this approach has the potential to reduce the number of attempts a surgeon makes to capture the desired tissue specimen, minimize tissue damage, improve speed of biopsy, and reduce patient discomfort

Reliability growth of autonomous underwater vehicle Dorado

Abstract -Underwater environments are highly unstructured, uncertain, and dynamic. However, over the past three decades many autonomous underwater vehicles (AUVs) have been developed and successfully deployed for various oceanographic applications. There is a growing need for the AUVs to be reliable for collecting useful data and samples for their users. An AUV is a typical one-of-a-kind product for which it is difficult to derive a mathematical/ statistical model for reliability prediction. The failure modes effects and criticality analysis (FM€CA) can produce more effective results. However, the assessment of reliability growth of an AUV is very important for predicting its operational success in challenging underwater environments. In this paper, we present the identification of different types of failures that occurred during the past one and a half years of operation of MBARlk Dorado AUV, classification of those failures, and the reliability growth analysis for the vehicle. Reliability issues of various subsystems and operational procedure of the AUV have also been discussed. A n extensive analysis of operational data and test results are presented in this paper