טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentHen Adi
SubjectDevelopment of a minimally invasive, brain-tumor removing
robot
DepartmentDepartment of Design and Manufacturing Management
Supervisor Professor Moshe Shoham
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

This research involves the development of a robot that performs neurosurgical procedures to remove malignant brain tumors. The robot is to be small and relatively light weight, in order to easily mount the robot onto the patient’s head. This allows for minimal discomfort during the surgery or operation. Moreover it is important that the treatment be minimally invasive and minimally damaging to healthy tissue.

Currently common tumor removal treatments are risky and complicated procedures, in which the surgeon creates an opening in the skull that is at least 30mm in diameter (called craniotomy). Surgery is performed under general anesthesia that is followed by a lengthy recovery. The unique structure of the robot allows the removal of tumors through a mere 6mm diameter opening. This significantly decreases the level of risk and leads to a shorter and easier recovery. The robot increases the precision of the operation over all.

The robot that has been developed as part of this thesis is a serial robot that drives two needles- a stiff, hollow external needle and a flexible internal needle. The internal needle protrudes out of the external needle perpendicularly through an opening at the bottom of the external needle. At the tip of the internal needle there is a sensor that allows the robot to locally distinguish between healthy and cancerous cells.  Furthermore, the tip of the internal needle has a device that allows the robot to treat cancerous cells once identified.

The treatment is performed by inserting the external needle through a 5mm hole in the skull until the internal needle senses the tumor tissue.  At which point the internal needle comes out perpendicular to the external needle and begins the process of identifying and treating malignant tissue. The internal needle advances linearly until it reaches the surface of the tumor and senses healthy cells. It then retracts back into the external needle. The external needle then rotates approximately 1° and the internal needle is then advanced until it reaches the surface of the tumor again. The process is repeated until the external needle rotates 360 °. Once a full 360° has been completed, the external needle is advanced into the tumor approximately 1 mm and the aforementioned process described is repeated. The tumor is treated layer by layer over its entire volume using this process.

In order to choose the most suitable method for moving the needles, a variety of different actuators were examined such as: piezoelectric actuators, pneumatic actuators and stepper motor with leading screw.

In addition to these mechanisms, a unique drive mechanism was examined, consisting of two wheels rotating in opposite directions to linearly drive the needle located between them.

After developing and manufacturing the robot, a preliminary test on a rat's brain was conducted. The experiment was conducted at Rambam Hospital in Haifa.  It should be noted the robot's internal needle is still in development. Therefore, only the robot's ability to rotate and advance the external needle within a rat’s brain were proven during the experiment.