Medical applications represent a unique chance of expansion for the optical fiber sensors (OFS) market that was
confined so far mostly in niche applications where higher technological costs were justified by OFS distinctive
advantages. Single use medical devices integrating OFS could however generate a significant growth for this type of
technology. Thanks to cost reductions derived from the success of optical fiber used in the telecom industry, it is now
possible to produce competitive disposable OFS for clinical environment. Cost reduction is nevertheless not the only
challenge for this type of application: materials bio-compatibility and sterilization resistance, packaging issues, design
considerations for end-user acceptance and operational simplicity, technology reliability including connectivity and
sensor performances, manufacturing process monitoring and outstanding quality control, are among few of the problems
that have to be considered to address correctly the complex medical market with successful disposable OFS devices.
With a clear understanding of the needs and challenges of clinical applications, it is easier to respond to this reality and
to offer commercially suitable solutions.
Although structural health monitoring and patient monitoring may benefit from the unique advantages of optical fiber
sensors (OFS) such as electromagnetic interferences (EMI) immunity, sensor small size and long term reliability, both
applications are facing different realities. This paper presents, with practical examples, several OFS technologies ranging
from single-point to distributed sensors used to address the health monitoring challenges in medical and in civil
OFS for medical applications are single-point, measuring mainly vital parameters such as pressure or temperature. In the
intra-aortic balloon pumping (IABP) therapy, a miniature OFS can monitor in situ aortic blood pressure to trigger
catheter balloon inflation/deflation in counter-pulsation with heartbeats. Similar sensors reliably monitor the intracranial
pressure (ICP) of critical care patients, even during surgical interventions or examinations under medical resonance
imaging (MRI). Temperature OFS are also the ideal monitoring solution for such harsh environments.
Most of OFS for structural health monitoring are distributed or have long gage length, although quasi-distributed short
gage sensors are also used. Those sensors measure mainly strain/load, temperature, pressure and elongation. SOFO type
deformation sensors were used to monitor and secure the Bolshoi Moskvoretskiy Bridge in Moscow. Safety of Plavinu
dam built on clay and sand in Latvia was increased by monitoring bitumen joints displacement and temperature changes
using SMARTape and Temperature Sensitive Cable read with DiTeSt unit. A similar solution was used for monitoring a
pipeline built in an unstable area near Rimini in Italy.
We present how fiber-optic temperature or pressure sensors could be applied to minimally invasive diagnostics and therapies. For instance a miniature pressure sensor based on micro-optical mechanical systems (MOMS) could solve most of the problems associated with fluidic pressure transduction presently used for triggering purposes. These
include intra-aortic balloon pumping (IABP) therapy and other applications requiring detection of fast and/or subtle fluid pressure variations such as for intracranial pressure monitoring or for urology diagnostics. As well, miniature temperature sensors permit minimally invasive direct temperature measurement in diagnostics or therapies requiring energy transfer to living tissues. The extremely small size of fiber-optic sensors that we have developed allows quick and precise in situ measurements exactly where the physical parameters need to be known. Furthermore, their intrinsic immunity to electromagnetic interference (EMI) allows for the safe use of EMI-generating therapeutic or diagnostic equipments without compromising the signal quality. With the trend of ambulatory health care and the increasing EMI noise found in modern hospitals, the use of multi-parameter fiber-optic sensors will improve constant patient monitoring without any concern about the effects of EMI disturbances. The advantages of miniature fiberoptic sensors will offer clinicians new monitoring tools that open the way for improved diagnostic accuracy and new therapeutic technologies.