Several major public health threats, from strokes to tumors, are currently diagnosed and treated under the guidance of x-ray fluoroscopy. While this technique has high spatiotemporal resolution, it only visualizes blood vessels, instead of the organs and tissues which these blood vessels supply. In addition x-ray fluoroscopy uses ionizing radiation, which is harmful to patients and physicians in large doses.
Researchers at UCSF have developed a concept and working prototype of a new catheter for use in an interventional magnetic resonance imaging (MRI) environment. A more robust image can be delivered in this environment, and the long-term radiation risk to the patient and physician is eliminated. The presence of a large constant magnetic field allows the possibility for remote navigation. The goal of this project is to develop a controller to enable safe, precise remote in situ navigation of such a catheter.
The device consists of a controllable current source that delivers current to the implanted coil, a temperature sensor to monitor the temperature of the coil, and a voltage sensor to monitor the voltage drop across the coil. From these measurements the coil resistance and power dissipation can be derived for complete monitoring of all thermal and electric parameters. The latest version of the device also handles footpedal control, bypassing the need for a separate device to handle user input.
The device is controlled by a PC running Labview. The device has a USB microcontroller which emulates a serial port. Labview uses its built in serial communication module to communicate with the device, issuing the amount of current to deliver and receiving current, voltage, temperature, and footpedal status. This cycle occurs every 10 milliseconds, sufficient for real-time perception.