Implantable sensor and system for measurement and control of blood constituent levels

A device for measuring and controlling the level of blood glucose in a mammal, comprising:

• an implantable source and sensor module adapted for (i) directing radiation at blood within vascular tissue, (ii) sensing the radiation after it has interacted directly with the blood within the tissue, and (iii) generating an output signal representative of the direct interaction of radiation with the blood within the tissue, the source and sensor module comprising at least one implantable source of radiation from infrared through visible light which emits radiation in at least two selected frequency bands, the source and sensor module adapted to be located out of direct contact with the blood, and adapted to be located with respect to the tissue to receive radiation affected by interaction with the blood within the tissue,
• means associated with the implantable source and sensor module for receiving the output signal and deriving therefrom a spectral output signal containing spectral information about the blood within the at least two selected frequency bands,
• a processor responsive to the spectral output signal for performing spectral analysis of the spectral output signal and deriving therefrom a control signal related to the level of the blood glucose, and
• an insulin pump for dispensing doses of insulin in response to the control signal.

A method for sensing in-vivo the level of at least one constituent of blood within mammalian vascular tissue, the method comprising the steps of:

• implanting in mammalian vascular tissue, and out of direct contact with blood to be analyzed, at least one implantable source of radiation from infrared through visible light, the source emitting radiation in at least two selected frequency bands, the at least one implantable source of radiation being arranged to direct the radiation at blood within the tissue, the radiation being affected by interaction with the blood,
• implanting at least one implantable detector located out of direct contact with the blood and being located with respect to the tissue to receive radiation affected directly by interaction with the blood,
• deriving from the detector an output signal containing spectral information about the blood within the at least two selected frequency bands, and
• processing the output signal to derive the level of the blood constituent.

A method for measuring and controlling the level of blood oxygen in a mammal comprising the steps of:

• implanting extravascularly an implantable source and sensor module in the mammal, the source and sensor module including at least one source of radiation from the infrared through visible light,
• directing the radiation through vascular tissue using the at least one source of radiation, the radiation being affected directly by interaction with blood within the tissue,
• sensing the radiation after it has passed through the tissue and generating an output signal representative of the sensed radiation by using the sensor module,
• spectrally analyzing the output signal using a processor module and deriving therefrom a control signal representative of the level of the blood oxygen, and controlling the level of the blood oxygen in response to the control signal.