3D SHAPE SENSING FOR MEDICAL APPLICATIONS WHITE PAPER
Overview of 3D shape sensing technology benefits
3D shape sensing – All surgical procedures performed in the medical industry may be classified as being non-invasive, minimally invasive, or invasive. These classifications generally refer to the degree to which medical instruments are introduced into the body.
While a great number of ailments may be treated non-invasively with various medical procedures, physicians must still rely on minimally invasive and invasive procedures to treat some conditions. Doctors and medical researchers are therefore constantly searching for ways to make such procedures safer, repeatable, and more cost-effective.
Some of the greatest breakthroughs in minimally invasive surgery include the development of medical endoscopes and the subsequent introduction of modern imaging methods such as fluoroscopy and intravascular ultrasound (IVUS).
These instruments and techniques give direct and indirect views of the heart, blood vessels, internal organs, and other parts of the anatomy to doctors, thus providing them with a wealth of information to guide their diagnostic and surgical decisions and actions.
In addition, these solutions can be equipped to remove blockages, deliver medicines, obtain samples, remove foreign objects, and in some cases, perform minor surgeries. A key benefit of minimally invasive medical devices is that they require only a small incision, often small enough to be sealed with a simple Band-Aid rather than staples or stitches.
3D shape sensing decreases healing and rehabilitation times
3D shape sensing significantly decreases healing and rehabilitation times, and it minimizes both functional and cosmetic damage to the body. Some such procedures, such as colonoscopies, are even performed on an outpatient basis. While these tools open a new landscape for better diagnosis and treatment, there are several drawbacks which limit their success. First, they can pose a significant risk to the patients as physicians manually guide the instruments through the gastrointestinal, pulmonary, or vascular systems. There is limited technology to aid physicians in this process, and individual experience and knowledge of human anatomy must be heavily relied upon.
While the physicians who perform these procedures are highly- trained, every patient is different and may represent a new challenge. Complications in invasive procedures may include internal bleeding, infections, as well as vessel wall and organ perforations. There are several common devices and techniques used to help mitigate these risks. The first and most familiar is the use of an endoscope featuring a light and lens or camera.
The instrument is guided through known internal tracts until an area or object of interest is discovered visually. However, knowledge of what path the endoscope is following within the body, whether it is sharply bent or obstructed at any point along its length, or even its precise location may be unknown. The physician can only see what is in front of the device and know only the general location of the instrument.
The second most widely used technique is fluoroscopy, which involves the use of x-ray imaging. Coronary catheterization, for example, relies on fluoroscopy to produce images of the cardiac system as the instrument is inserted or retracted. On the way to the target location, the technician or physician must periodically perform and assess X-ray imaging to determine the catheter’s location, whether they are headed in the correct direction, and if they have reached their target location.
This method complicates the procedure and extends its duration. It also increases the doses of radiation a patient and the medical staff must be exposed to. Additionally, in an effort to minimize the radiation exposure of the patient and the physician, they have limited time to determine the position of the instrument and decide whether to proceed or backtrack. These risks and limitations remain undesirable to many.
A third but less utilized method is intravascular ultrasound (IVUS) imaging which provides the location of the entire catheter or endoscope nearly in real-time. However, this method’s reliance on the reflection of high-frequency sound pulses from interfaces within the body has several drawbacks. These interfaces, such as those between blood and vessel or fat and organ, do not produce sufficient reflections to enable consistently clear imaging. The contrast and resolution of the images generated by ultrasonic transducers are therefore often difficult to interpret and unreliable.
There is also an inherent tradeoff between spatial resolution and signal penetration depth. Because endoscopes and imaging catheters are very thin and follow complex paths, multiple transducers, or sensors, must be used and constantly adjusted to obtain a meaningful image of the instrument. This adds to the complexity and duration of the procedure.
The advent and development of linearly-continuous shape sensors based on optical fiber can aid in navigating and positioning endoscopes and catheters by overcoming several of the shortcomings of traditional methods. Optical shape sensors are very small in diameter…
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