Abstract- This paper presents some initial concepts in the design and development of actuating systems based on shape memory alloy for Minimally Invasive Surgery (MIS). Specially the motivation is to design tissue/fluid storage mechanism which can be used to collect samples from the surgical area for further diagnostic procedure. The proposed hybrid design combines passive source of energy with the active source. The passive source is based on the storage of spring energy and the active source is based on utilization of shape memory alloy as a part of switching mechanism. Various design concepts for the switching mechanism are presented combined with the design of their prototypes. Keywords - Minimally Invasive Surgery (MIS), tissue/liquid storage mechanisms, hybrid actuating system, shape memory alloy I. INTRODUCTION Over the last twenty years, minimally invasive surgery (MIS) has become the method of choice for a number of surgical procedures. While open surgery requires the creation of large access wounds in order to expose the relevant anatomy and allow room for manipulation, resulting in a high ratio of access wound trauma to procedure trauma, MIS provides access to the operation site via small wounds, dramatically reducing post-operative pain and shortening recovery times. However, while MIS offers tremendous advantages for the patient, it still suffers from a number of inherent problems that limit its application [1]. Unlike open surgery, MIS requires that all instruments required for the operation pass through a small 5 or 10 mm access port. This constraint has dramatically affected the nature of instrument design and, to some extent; the future of MIS depends on how well this problem is addressed by the engineering community. The capabilities of MIS can only advance so far without a radical redesign of the devices presently being used. With this motivation in mind, we are looking into ways by which we can develop the next generation of surgical tools. The specific area of investigation that interests us at this time is that of tissue and fluid sampling and modeling. One of the most significant capabilities offered by MIS techniques is the ability to examine and diagnose possible afflictions without making any significant access wounds. In some cases, diagnosis requires an examination via endoscope or optical catheter while in other cases it also requires a biopsy of specific body tissue or fluid. Tools previously designed to collect these samples during open surgery must now be redesigned to work in a minimally invasive setting. In order to effectively design tools to interact with body fluids and tissues in particular, engineers must have a thorough understanding of the mechanical behavior of these materials. To model this behavior, however, a large amount of data must be collected from living tissues. Providing access to these tissues in situ is another area where MIS becomes very useful, provided the right tools are available. We are therefore investigating the design of tools not only for practicing minimally invasive surgery, but for measuring the mechanical response of living tissues during minimally invasive surgery. This paper presents some new concepts for designing actuating mechanism, which can be used in the design of fluid sampling and tissue collecting mechanism. The design is based on hybrid actuation concept where both the active and passive sources are combined which can result in an effective approach in MIS application. In the following, first we present some general category of tissue manipulation in MIS, then an overview of actuation concepts and finally various design prototypes that have been developed. II. TISSUE MANIPULATION TASKS A. Tissue Identification During a biopsy tissue sampling procedure, it is often required to remove a sample from a specific organ; therefore, before any sample can be taken the correct organ must be positively identified. This usually requires that the organ be within visual range of the surgeon. It would be useful to have a biopsy sampling tool that can assist the surgeon with the task of identifying the correct tissue either by providing additional visual information (such as by carrying an optical fiber etc.), or perhaps by somehow “pre-sampling” or otherwise testing the tissue by non-visual means. An example would be to use sensors to collect preliminary force/displacement (elasticity) data on the organ in question [2]. B. Tool Guiding and Placement Often a very specific piece of tissue, such as a small potentially cancerous area, must be located and sampled. This requires very precise placement of the biopsy tool during the sample excision. The surgeon needs to know that the sample has been taken from the exact area required and not from the surrounding tissue. This can be challenging, Design and Development of Actuating System for Diagnostics Application in Minimally Invasive Surgery (MIS) Shahram Payandeh, Jason Rothe and Ash Parameswaran Experimental Robotics Laboratoty, School of Engineering Science Simon Fraser University, Burnaby, British Columbia, Canada, V5A 1S6