Wednesday, September 18, 2013

Low-cost, small animal thermal ablation system

 The goal of this project was to develop a cheap, simple and robust ablation system for creating small thermal lesions in animals. As soon as biological tissues are exposed to temperatures > 40 degree Celsius for several minutes (~>30) tissue necrosis occurs and introduces cell death. This technique is used in cancer therapy to kill cells and to destroy tumors. 
Schematic of small animal ablation example in a mouse brain to study brain cancer treatments.
The understanding of ablation techniques and the development of heating algorithms/strategies rely on animal research studies. To provide a low cost system for ablation studies in small animals (mice,rats) I developed a simple system including a graphic user interface.

Schematic connection sketch for the micro-controller and electronic board.
The system uses an Arduino-Uno Micro-Controller (MC) board and an ordinary, resistive thermistor. The graphic user interface (GUI) communicates with the MC about 4 times per second. In a first request voltage is read from the thermistor to determine the actual temperature. Then in a second step the GUI/program calculates the necessary voltage to reach the required set-temperature (defined by user) and  sends the info to the MC. On the MC the voltage reaching the thermistor will be set accordingly. An integrated PI (proportional/integral) controller regulates the voltage to keep the temperature at the thermistor constant.
Graphic user interface for the Thermistor control
Total costs of the utilities < $50 (Micro controller board $25, Thermistor $8, Wires, etc $17)


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