Method of determining a property of a fluid and spectroscopic system

A spectroscopic system for determining a property of a substance comprising:

• an imaging system which monitors a position of a volume of interest,
• an objective having a focal point for performing an optical detection,
• a spectroscopic system including:
• a laser which provides a stationary, incident measurement laser beam that is larger than and encompasses the volume of interest and the objective, and
• a spectrometer which spectroscopically analyzes laser light returned from the volume of interest via the objective;
• an actuator which moves the objective and the focal point transversely relative to the stationary incident measurement laser beam;
• a controller responsive to the imaging system to control the actuator to move the objective such that the focal point is maintained positioned in the volume of interest.

A method of providing an in vivo analysis of blood comprising:

• using an imaging system to locate an objective relative to a blood vessel;
• moving the objective such that a focal point of the objective is aligned with the blood vessel;
• forming a feedback loop such that the position of the objective is compared to the position of the blood vessel after movement of the objective and the objective is moved again until the focal point aligns with the blood vessel;
• using a spectroscopic system to direct a laser light beam through the objective and onto the blood vessel;
• and
• using return light to perform a spectroscopic analysis of the blood in the blood vessel.

An apparatus for providing in vivo analysis of blood, the apparatus comprising:

• an objective having a focal point;
• an imaging system that determines a current position of the objective relative to a target blood vessel;
• a feedback loop which compares the current position of the objective focal point relative to the target blood vessel and moves the objective until the focal point coincides with the target blood vessel;
• a laser that directs laser light through the objective to the focal point;
• and
• a spectrometer which analyzes light returned through the objective to determine one or more properties of blood in the target blood vessel.