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Digital archive of theses discussed at the University of Pisa


Thesis etd-02082011-121053

Thesis type
Tesi di dottorato di ricerca
email address
Thesis title
Image guided robotic assistance for the diagnosis and treatment of tumor
Academic discipline
Course of study
relatore Prof. Pietrabissa, Andrea
tutor Prof. Ferrari, Mauro
relatore Dott. Ferrari, Vincenzo
  • Computer Assisted Surgery
  • Robotic Surgery
  • Ultrasound guided robotic system
Graduation session start date
The aim of this thesis is to demonstrate the feasibility and the potentiality of introduction of robotics and image guidance in the overall oncologic workflow, from the diagnosis to the treatment phase.
The popularity of robotics in the operating room has grown in recent years. Currently the most popular systems is the da Vinci telemanipulator (Intuitive Surgical), it is based on a master-slave control, for minimally invasive surgery and it is used in several surgical fields such us urology, general, gynecology, cardiothoracic. An accurate study of this system, from a technological field of view, has been conducted addressing all drawbacks and advantages of this system. The da Vinci System creates an immersive operating environment for the surgeon by providing both high quality stereo visualization and a human-machine interface that directly connects the surgeon’s hands to the motion of the surgical tool tips inside the patient’s body. It has undoubted advantages for the surgeon work and for the patient health, at least for some interventions, while its very high costs leaves many doubts on its price benefit ratio.
In the robotic surgery field many researchers are working on the optimization and miniaturization robots mechanic, while others are trying to obtain smart functionalities to realize robotic systems, that, “knowing” the patient anatomy from radiological images, can assists the surgeon in an active way.
Regarding the second point, image guided systems can be useful to plan and to control medical robots motion and to provide the surgeon pre-operative and intra-operative images with augmented reality visualization to enhance his/her perceptual capacities and, as a consequence, to improve the quality of treatments.
To demonstrate this thesis some prototypes has been designed, implemented and tested.
The development of image guided medical devices, comprehensive of augmented reality, virtual navigation and robotic surgical features, requires to address several problems. The first ones are the choosing of the robotic platform and of the image source to employ.
An industrial anthropomorphic arm has been used as testing platform. The idea of integrating industrial robot components in the clinical workflow has been supported by the da Vinci technical analysis.
The algorithms and methods developed, regarding in particular robot calibration, based on literature theories and on an easily integration in the clinical scenario, can be adapted to each anthropomorphic arm. In this way this work can be integrated with light-weight robots, for industrial or clinical use, able to work in close contact to humans, which will become numerous in the early future.
Regarding the medical image source, it has been decided to work with ultrasound imaging. Two-dimensional ultrasound imaging is widely used in clinical practice because is not dangerous for the patient, inexpensive, compact and it is a highly flexible imaging that allows users to study many anatomic structures. It is routinely used for diagnosis and as guidance in percutaneous treatments. However the use of 2D ultrasound imaging presents some disadvantages that require great ability of the user: it requires that the clinician mentally integrates many images to reconstruct a complete idea of the anatomy in 3D. Furthermore the freehand control of the probe make it difficult to individuate anatomic positions and orientations and probe repositioning to reach a particular location. To overcome these problems it has been developed an image guided system that fuse 2D US real time images with routinely CT or MRI 3D images, previously acquired from the patient, to enhance clinician orientation and probe guidance.

The implemented algorithms for robot calibration and US image guidance has been used to realize two applications responding to specific clinical needs. The first one to speed up the execution of routinely and very recurrently procedures like percutaneous biopsy or ablation. The second one to improve a new completely non invasive type of treatment for solid tumors, the HIFU (High Intensity Focused Ultrasound).
An ultrasound guided robotic system has been developed to assist the clinician to execute complicated biopsies, or percutaneous ablations, in particular for deep abdominal organs. It was developed an integrated system that provides the clinician two types of assistance: a mixed reality visualization allows accurate and easy planning of needle trajectory and target reaching verification; the robot arm equipped with a six-degree-of-freedom force sensor allows the precise positioning of the needle holder and allows the clinician to adjust, by means of a cooperative control, the planned trajectory to overcome needle deflection and target motion.
The second application consists in an augmented reality navigation system for HIFU treatment. HIFU represents a completely non invasive method for treatment of solid tumors, hemostasis and other vascular features in human tissues. The technology for HIFU treatments is still evolving and the systems available on the market have some limitations and drawbacks. A disadvantage resulting from our experience with the machinery available in our hospital (JC200 therapeutic system Haifu (HIFU) by Tech Co., Ltd, Chongqing), which is similar to other analogous machines, is the long time required to perform the procedure due to the difficulty to find the target, using the remote motion of an ultrasound probe under the patient. This problem has been addressed developing an augmented reality navigation system to enhance US guidance during HIFU treatments allowing an easy target localization. The system was implemented using an additional free hand ultrasound probe coupled with a localizer and CT fused imaging. It offers a simple and an economic solution to an easy HIFU target localization.
This thesis demonstrates the utility and usability of robots for diagnosis and treatment of the tumor, in particular the combination of automatic positioning and cooperative control allows the surgeon and the robot to work in synergy. Further the work demonstrates the feasibility and the potentiality of the use of a mixed reality navigation system to facilitate the target localization and consequently to reduce the times of sittings, to increase the number of possible diagnosis/treatments and to decrease the risk of potential errors. The proposed solutions for the integration of robotics and image guidance in the overall oncologic workflow, take into account current available technologies, traditional clinical procedures and cost minimization.