Strain Sensing and 3D Imagery
Most people think of strain testing and sensing in terms of traditional industries like aerospace, automotive and robotics – actually, most people probably don’t think of strain testing very often. When engineers think of strain sensing they might picture stress tests on large aircrafts, cars with crash test dummies, and lines of robots in a factory. However strain sensing can be used throughout many industries. In fact, strain sensing rarely relates to a single change measurement. Structural shape determination, or shape sensing can be calculated by applying specific algorithms to a simple strain measurement.
Fiber Optic Sensing (FOS) technology, using Fiber Bragg Gratings can take measurements in the most minuscule of places by aligning 3 fibers together in a single package. This can be done with traditional fibers organized at 120 degrees, or with a specially developed 3-core fiber. The strain value of each fiber is sent to a processor in the system, and then interpreted by an algorithm so that the 3-dimensional position of the fiber can be correctly rendered on a monitor in real time.
Medical Imaging and FOS Strain Measurement
The industries that can successfully adapt FOS shape sensing to improve current practices are numerous, but one of the most novel applications for this technology is in the biomedical sector. For example, Sensuron’s FOS technology has been utilized with great success to improve the accuracy and effectiveness of medical imaging devices, such as catheters and endoscopes. These instruments give indirect views of the heart, blood vessels and internal organs to doctors. The development of FOS technology in medical imaging has been extraordinary and can change the way physicians practice internal medicine. Using such techniques, patients require only a small incision, which significantly decreases the healing and rehabilitation times for patients, not to mention the minimized damage, both functional and cosmetic to the body.
Unlike techniques using FOS technology, current imaging procedures have some commonly unforeseen drawbacks. They can pose a significant risk as doctors must manually guide the instruments through the body’s very sensitive and complicated systems. There is a limit to the amount of information the devices supply to aid the physician, which unfortunately allows too much room for human error. Complications from these procedures include internal bleeding, adhesions, infections and vessel wall or organ punctures.
Although physicians are highly trained and specialists are very adept at using these current devices, the complexity of the human body proves to be a major challenge in avoiding these complications. There are a few traditional methods used to aid doctors as they guide the technology through the body. Endoscopes today usually feature a light and camera so that the instrument can be guided and medical condition they are searching for is discovered visually. This was an elegant solution for identifying the foreign object or damage to the body itself, but leaves a lot of room for error when then trying to determine, where, in the body the condition is exactly so that surgeons can then go in to fix the problem. Another very common practice for imaging is angiography, which uses catheters to navigate inside the body. Technicians release a small amount of radio contrast agents that will appear on X-rays to produce accurate images of the body’s infinitely complicated systems and vessel ways. This method not only extends the duration of the procedure, as periodic stops are necessary to release the agent, it also introduces and exponentially increases the amount of foreign material and radiation exposure.
FOS and 3D sensing
Both of these methods are effective, but limiting. With the development of FOS to determine shape and space through strain measurement, there is a better way to improve the effectiveness of imaging procedures while reducing human health risk. The optic sensing fibers that make up FOS instruments are extremely small in diameter and chemically inert, which allows easy integration to existing technologies. Once the fibers are connected to an existing endoscope or imaging machine, the data that the sensors generate can provide information about the exact location along the entire length of the instrument. The strain measurement readings can be plotted into 3-D readings in real-time and displayed visually, which improves positional awareness and provides essential guidance of the instrument as it navigates through the body. This is all done with no foreign chemicals or radiation.
Better informed doctors, minimized complexity and better tracking are all results of using strain measurement to improve device accuracy. The FOS solution equates to reduced risk of complication during procedures, quicker recovery, and thus better long-term health for patients. Meanwhile, physicians and technicians will see improvement in the quality of their diagnoses when using optical shape sensing through strain measurement, providing higher fidelity real-time information. New instruments and procedures utilizing fiber optic shape sensors will ensure that skilled physicians have the tools needed to increase the probability of success and lead to safer, repeatable and effective methods.
Sensuron is a leading global provider of fiber optic sensing systems that use light to test, measure, control, inspect, assist with operation and ensure safety of innovations across aerospace, medical and energy industries.