CONTROL UNIT

The control unit, as shown in Figure 7, consists of sensors, a microcontroller, pumps, reservoirs, a wireless transceiver and power supply and management. Besides the VEGF spectrometer, other sensors such as for temperature, pH and pressure are embedded at the tip of the intratumoral catheter to monitor the physiological condition of the tumor locally. Small signal wires embedded in the catheter permit the microcontroller to acquire information from these sensors. An additional sensor, the Aptamar BioSensor™, which represents an advanced method for detection of VEGF, is currently in development by PKC.

The microcontroller selected is built around a low-power, versatile 16-bit CPU that is widely used in wireless RF, battery powered applications and FDA approved medical devices. The microcontroller is fully supported by its manufacturer with numerous software development and simulation tools for rapid implementation. The versatile microcontroller has several peripheral interfaces, runs a real-time operating system and can execute at various low power modes.

The wireless transceiver is based on MICS, which is an ultra-low power, unlicensed, mobile radio service dedicated to transmitting data to support diagnostic or therapeutic functions associated with implanted medical devices such as pacemakers, implanted cardioverter defibrillators, neurostimulators and drug pumps, operating in FCC approved medical implant wireless band. The transceiver supports high data rate at extremely low power modes. The MICS band permits patients and medical practitioners to interact with the functions of the implant devices without causing interference to other users of the electromagnetic spectrum. Via a wireless connection to a local base station connected to the Internet, the wireless transceiver permits the implant unit to communicate with the care provider’s personal computer or handheld device.

Power charging is accomplished by an inductive method using magnetic coils. The implant unit contains a set of coils that receives power from the magnetic field generated by the primary coils in the charger unit near the patient. This wireless charging technology has been in existence for over one hundred years but was recently popularized by the demand to recharge consumer electronics devices wirelessly. With the wireless charging capability, the implant unit can be designed with a smaller battery, significantly reducing the size of the overall implant unit.