The principle of the Luciole System is based on the absorption of certain part of the light spectrum (called Near InfraRed due to its proximity to the red light) by hemoglobin (the oxygen carrier of the blood). The signal propagated within the brain needs to be analyzed. Even though the scientific principle has been known for more than 60 years, the signal treatment and the propagation of the Near Infrared Light was only recently fully understood.


Our neuromonitoring system is based on optical extinction measurements in the near infrared region. The method is based on the well-established near infrared spectroscopy (NIRS) principle. In this region of the spectrum light penetrates biological tissue. Blood, in particular its constituents oxygenated and deoxygenated hemoglobin act as absorbing constituent against the background and therefore allows for quantification of their concentrations.

Using an appropriate tissue model as a basis for the evaluation algorithms allows extracting the absolute concentrations of oxygenated and deoxygenated blood and brain water. The dynamics of these parameters allows to observe changes in integrity of the monitored tissue.

RheoSens probe

Selected Publications

M. Seule, C. Sikorski, O. Sakowitz, G. von Campe, E. Santos, B. Orakcioglu, A. Unterberg, E. Keller, (2016), Evaluation of a New Brain Tissue Probe for Intracranial Pressure, Temperature, and Cerebral Blood Flow Monitoring in Patients with Aneurysmal Subarachnoid Hemorrhage, Neurocritical Care, Volume 25, Issue 2, pp 193–200.

E. Keller, J. Froehlich, D. Baumann, C. Böcklin, C. Sikorski, M. Oberle, M. Muser, (2015), Detection of Delayed Cerebral Ischemia (DCI) in Subarachnoid Haemorrhage Applying Near-Infrared Spectroscopy: Elimination of the Extracerebral Signal by Transcutaneous and Intraparenchymatous Measurements in Parallel, in Neurovascular Events After Subarachnoid Hemorrhage, Acta Neurochirurgica Supplement Volume 120, pp 243-247.

C. Böcklin, D. Baumann, F. Stuker, J. Fröhlich, (2015), Mixing formula for tissue-mimicking silicone phantoms in the near infrared, J. Phys. D: Appl. Phys. 48 (10).

C. Böcklin, D. Baumann, J. Fröhlich, (2014), New approach for absolute fluence distribution calculations in Monte Carlo simulations of light propagation in turbid media, Journal of Applied Physics, Vol. 115, Issue 6, pp.DOI: 10.1063/1.4865171.

E.Keller, J. Fröhlich, C. Muroi, C. Sikorski, M. Muser, (2011), Neuromonitoring in intensive care: A new brain tissue probe for combined monitoring of intracranial pressure (ICP), cerebral blood flow (CBF) and oxygenation, Acta Neurochirurgica (Supplement), Vol. 110, Issue 2, pp.217-20.

N. F. Newman et al., (2001), Longitudinal assessment of neurocognitive function after coronary-artery bypass surgery, The New England Journal of Medicine, Vol. 344, No. 6, pp. 395-402.


Six patent families protect the Rheo System. The first two patents are held by the University and ETH Zurich, who grant an exclusive license to Luciole Medical AG. Two patents owned by Luciole Medical have been approved in different regions already. Furthermore, Luciole Medical has applied for two more patents that are currently in the nationalization phase.

List of selected patents of the different patent families:

Probe and apparatus for measuring cerebral hemodynamics and oxygenation (EP1301119 (B1))

Device for measuring blood-flow in an organ (EP1464276 (B1))

Device for diagnosis and /or therapy of physiological characteristics of a selected portion of the body by optical reflectance or optical transmission (EP2168475 (B1))

Measuring device for measuring cerebral parameters (US9668681 (B2))

Measuring device for determining cerebral parameters, pending

Measurement System and Method for Measuring Parameters in a Body Tissue, pending