R. Ahmadi

Publications (2)1.52 Total impact

• Article: Discretely Loaded Beam-Type Optical Fiber Tactile Sensor for Tissue Manipulation and Palpation in Minimally Invasive Robotic Surgery

  R. Ahmadi, M. Packirisamy, J. Dargahi, R. Cecere
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  ABSTRACT: In traditional open surgery, surgeons use their fingertip palpation to investigate the hidden anatomical structures of tissue. However, in the current commercially available minimally invasive robotic surgery (MIRS) systems, while surgical instruments interact with tissues, surgeons do not sense any tactile information. Therefore, tactile sensors are required to be integrated into the tips of surgical instruments to mimic the perception of the surgeon's fingertips. The electrically based tactile sensors that exist at present cannot usually operate under static loading conditions. In addition, they are not compatible with magnetic resonance imaging (MRI) devices. Therefore, this research was aimed at restoring tactile information by developing an MRI compatible optical fiber tactile sensor. The sensor consists of only one single moving part. Thanks to this novel design, the sensor does not require the use of an array of sensors to measure the distributed tactile information. This capability simplifies the integration of the sensor into any suitable space available at the tips of surgical instruments. In addition, the sensor performs under both static and dynamic loading conditions. A theoretical model of the sensor and a finite-element model of the sensor-tissue interaction were developed. To validate the sensor, a prototype of the sensor was fabricated and tested.
  IEEE Sensors Journal 02/2012; · 1.52 Impact Factor
• Conference Proceeding: Design, fabrication, and testing of a piezoresistive hardness sensor in Minimally Invasive Surgery

  M. Kalantari, M. Ramezanifard, R. Ahmadi, J. Dargahi, J. Kovecses
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  ABSTRACT: In the present paper, a novel and reliable tactile sensor is proposed to provide the required tactile feedback to the surgeon allowing the annuloplasty surgery to be performed by Minimally Invasive Surgery (MIS) techniques. The proposed sensor can differentiate between the hardness of different kind of elastomers. The structure of the sensor is very simple and it can easily be microfabricated, and integrated to various surgery devices such as catheters. The paper discusses the design, modeling, and fabrication of the sensor. Several hardness measuring tests are carried out on the sensor and the output is compared to a standard method of hardness measurement by a durometer. Two elastomers with hyperelastic behaviour, representing two different heart tissues were modelled mathematically to verify the sensor's output. It is shown that the output of the sensor is reliable.
  Haptics Symposium, 2010 IEEE; 04/2010