A reliable eye on health

It’s essential that rigid endoscopes function perfectly to avoid risks for patients and medical staff. Reliable quality testing is intended to exclude risks from infections and injuries, but also misdiagnoses. In many countries, hospitals are required to regularly check and maintain endoscopes to ensure they function properly and don’t contain germs. In addition, there are European guidelines and standards regulating the quality assurance of rigid endoscopes. These checks are carried out by specially trained staff and include endoscopy tests and sterilization tests, as well as extensive visual inspections.

The Dutch company Dovideq Medical Systems B.V. specializes in measuring instruments for minimally invasive surgery. The current product range is aimed at central sterilization departments in hospitals, endoscope manufacturers, and endoscope repair companies. For the inspection of rigid endoscopes, Dovideq Medical Systems has developed various automated and networked systems. Particularly handy, small, light, cost effective, and fast is the automatic endoscope tester LightControl. Using six test and measurement parameters, detailed data on the condition of the endoscope is recorded and evaluated, ensuring only flawless endoscopes reach the operating theater.

The LightControl system ensures a high degree of efficiency and reliability with the help of IDS cameras from the LE camera family.

Quality defects and the impaired functioning of an endoscope can have various origins. In addition to incorrect handling and lack of maintenance, these include factors such as material fatigue and contamination. Improper transport or unsuitable storage can also lead to damage, as can the simple aging of the medical device. Lenses and other optical components can wear out over time, resulting in blurred or distorted images. To prevent bacteria or other pathogens from settling on the endoscope, impairing the quality of the images and possibly harming the patient, they’re regularly sterilized. However, the sterilization process can also affect quality and accuracy as the high temperatures and chemical substances used in the process can potentially harm the sensitive endoscope components. Heat and steam can trap moisture in the lenses and cause damage while some sterilizing substances, such as formaldehyde, can be corrosive to metal parts.

To efficiently deal with the complexity of the required inspection criteria, Dovideq Medical Systems developed the LightControl visual inspection system.

“With the help of the camera, it sees far more than the human eye of a surgeon, for example dirt particles, lens fractures, impurities, or color deviations,” explains Chielant de Wit, managing director of Dovideq Medical Systems.

LightControl runs the automated visual inspection with the aid of a uEye LE camera from IDS. Price, sensor, and size were decisive factors in the choice of model. The built-in USB3 Vision industrial camera U3-3860LE Rev.1.2 is reduced to essential functions and has a light-sensitive Sony sensor. The integrated IMX290 with back-side-illumination (BSI) technology ensures excellent image quality with clean color separation, and enables true-to-life reproduction of the subject, very important under poor or fluctuating lighting conditions. The camera is small and versatile, making it ideal for integration into small devices and embedded systems in medical technology. For automated quality inspection of endoscopes, Dovideq has identified six test and measurement parameters for the camera to examine and provide detailed feedback in real time:

The lens fracture algorithm measures whether internal lenses have a fracture. The particle detection algorithm determines whether fine dirt particles, moisture, or other contaminants have entered the internal areas of the endoscope. For both measurements, the camera takes several pictures and makes a histogram. The system references the images in relation to previous images and feeds this data into a neural network.

Light fibers are measured in lux, based on light emission. The light fiber measurement uses reference values to ensure the fibers or fiber bundles of the endoscope allow enough light to pass through. This prevents the endoscope from providing unclear images.

Light transmission through the lenses is determined by individual images from the integrated IDS camera. The measuring device uses a calibrated light source on a pixel plane. Each pixel is assigned a specific RGB value of a color spectrum. All pixels are converted into a luminance value and referenced with the help of a specially developed algorithm.

The focus measurement uses the scientific Harr wavelet transformation to check whether the lenses are intact and not contaminated or whether the endoscope provides a clear image. During the measurement, the system takes several pictures to verify the condition of each lens. In the optimal case, the camera looks through the endoscope and shows sharp contours. Color correction detects discoloration due to the sterilization process, with the system warning against misinterpreting images due to color deviations. The unit takes images and measures deviations in color transmission using the hue, saturation, and value (HSV) model, which describes the color of a pixel based on those three values. Color correctness ensures the actual colors of organs or tissues are reproduced to avoid incorrect diagnosis or treatment.

“With the help of the test and measurement details, information about the performance of the tested endoscopes can be evaluated and history and trend analyses can be created,” de Wit explains. LightControl stores all details of the endoscope measurements, together with the test results, in a database called EndoscopeManager for reporting and management purposes, enabling dedicated management and quality reporting. The automated visual inspection of endoscopes serves quality assurance, efficiency, cost-effectiveness, and patient safety in hospitals and medical practices,” de Wit notes. “Systems like LightControl make a significant contribution to this by providing objective results and detecting even the smallest defects, scratches, or wear on endoscopes. They always work with the same accuracy and consistency, regardless of factors such as fatigue or human error, and are much faster. This saves time and costs, leads to higher equipment availability, and improved resource utilization. Potential defects or damage are detected at an early stage, avoiding costly repairs or replacement of endoscopes. The resulting images or videos are available as proof of inspection and can be used for fault analysis and training purposes if required.”

Outlook

“Endoscopes are vital medical devices enabling doctors to diagnose and treat a variety of conditions by providing a clear, internal view of a patient’s body. However, like any medical device, endoscopes are subject to wear and tear, and over time they may need to be repaired or replaced,” de Wit says.

Already now the demand for automated intelligent visual inspection of endoscopes is high and is expected to increase in the coming years. In particular, due to the increasing number of endoscopy procedures and the growing sensitivity to infection risks, the demand for automated inspection technologies will become stronger. In addition, artificial intelligence (AI) will help improve the efficiency and accuracy of inspection processes and minimize human error.

The needs of the health sector are evolving as fast as the technologies used in this field. The use of IDS cameras is increasingly proving its worth here.

“In medical technology, the demand for our products has increased particularly in the past year, which pleases us not only from an economic point of view,” explains IDS Managing Director Jan Hartmann. “More and more IDS cameras are thus making a contribution to health promotion worldwide.”