1. Rigid Endoscope Stage (1806-1932): Beginning with the candlelight metal tube instrument invented by Philipp Bozzini, it was primarily used for urological examinations, limited by its rigid structure and thermal light source technology;
2. Semi-Flexible Endoscope Stage (1932-1957): The Wolf-Schindler gastroscope, with its lens array and 30° bending angle, enabled gastric visualization for the first time, marking a breakthrough in operability;
3. Fiberscope Stage (1957-1983): Basil Hirschowitz's team developed the first cold-light flexible endoscope based on Hopkins fiber optic technology, resolving the core conflict between image transmission and patient comfort;
4. Electronic Endoscope Stage (1983-Present): Welch Allyn pioneered the use of CCD sensors instead of optical fibers to achieve electronic signal imaging, increasing resolution to 4K and pioneering a new model for digital diagnosis and treatment.
5. Capsule Endoscopy (2000-Present): Given Imaging's wireless capsule endoscope, developed by Given Imaging, overcomes the blind spot of small bowel examinations, allowing a single examination to cover the entire digestive tract, driving innovation in non-invasive diagnostic technology.
In modern medicine, medical endoscopy technology has made significant progress. Endoscope types have greatly expanded to include flexible, semi-flexible, and rigid endoscopes.
In terms of imaging principles, in addition to traditional optical endoscopes that rely on optical lens systems to achieve imaging, electronic endoscopes, leveraging advanced electronic imaging technology, have emerged as a significant component of the endoscopic imaging field. Electronic imaging technology not only provides clearer and more accurate images but also significantly enhances doctors' ability to observe and diagnose lesions.
In terms of application scenarios, medical endoscopes have a wide range of applications, now covering multiple key hospital departments. These include gastroenterology, which focuses on the diagnosis and treatment of digestive system diseases; ENT, which diagnoses and treats diseases of the eyes, ears, nose, and throat; general surgery, which performs general surgery and manages related conditions; and urology, which diagnoses and treats urinary system diseases.
Notably, medical endoscopes are trending toward multifunctionality. This trend aims to further enhance the effectiveness and value of endoscopes in medical diagnosis and treatment by integrating multiple functions, providing patients with more precise and efficient medical services and advancing medical technology to a higher level.
Classification and Application
As an indispensable diagnostic and therapeutic tool in modern medicine, medical endoscopes are categorized in various ways based on their characteristics. The following is a professional explanation of common medical endoscopes based on three key dimensions: number of uses, imaging principle, and the rigidity of the scope:
Classification by Number of Uses
Disposable Medical Endoscopes: These endoscopes are designed to be disposable after a single use, minimizing the risk of cross-infection. Their relatively simple structure and low cost typically provide basic imaging and operating functions, meeting the needs of specific examination scenarios.
Disposable medical endoscopes are primarily used in medical settings with stringent infection control requirements, such as diagnostic examinations of patients with highly infectious diseases, or in resource-limited environments where high-level disinfection is difficult to maintain.
These endoscopes do not require complex cleaning and disinfection procedures after use, preventing the risk of nosocomial infections caused by incomplete disinfection and providing a strong guarantee for medical safety.
Reusable medical endoscopes: These endoscopes feature high durability and sophisticated construction, enabling repeated clinical use after rigorous cleaning and disinfection procedures. While their reusability may result in a relatively high cost, they offer excellent long-term economic benefits. Reusable medical endoscopes are widely used in a variety of routine medical examinations and treatments, including in specialized fields such as gastroenterology, respiratory medicine, and urology, providing physicians with accurate diagnostic evidence and effective treatment options. However, to ensure safety and performance, strict disinfection and sterilization procedures must be followed after each use, as well as regular maintenance and servicing.
Classification by Imaging Principle
Optical endoscopes: As an early product in the development of medical endoscopes, optical endoscopes primarily rely on optical systems to achieve imaging. Through a series of optical components, such as lenses and prisms, they transmit images of the human body's interior directly to the eyepiece, allowing the physician to directly observe the morphology and structure of the target area.
Optical endoscopes offer high resolution and true color reproduction, clearly capturing subtle tissue features. However, their relatively complex structure limits operational flexibility, and imaging quality may be affected in curved areas. Despite this, optical endoscopes still play an important role in certain specific areas, such as simple direct-view examinations of the body surface or cavity.
Electronic endoscopes: With the rapid advancement of electronic technology, electronic endoscopes have gradually become the mainstream type of endoscope in clinical practice. They feature a miniature camera installed at the front of the endoscope, which converts captured image signals into electrical signals and transmits them via wires to image processing equipment. The processed image is clearly displayed on the monitor in the form of a digital signal, providing doctors with an intuitive and accurate perspective.
Electronic endoscopes not only offer high-resolution imaging capabilities but also enable image storage, playback, and transmission, facilitating remote consultations and the accumulation and analysis of case data. Furthermore, electronic endoscopes can be equipped with various functional modules, such as narrowband imaging (NBI) and autofluorescence imaging (AFI), to further enhance the ability to diagnose pathological tissues. Electronic endoscopes are widely used in diverse fields, including digestive endoscopy, bronchoscopy, and laparoscopy, significantly advancing the development of modern medical diagnostic and treatment technologies.
Fiberoptic endoscopes: Fiberoptic endoscopes combine the advantages of optical and electronic technologies, using optical fibers to transmit light and image signals. The excellent flexibility and bendability of optical fibers enable endoscopes to penetrate deeply into complex cavities and organs within the human body.
At the front end of a fiberoptic endoscope, light is transmitted to the target site via a fiber bundle. The reflected light is then transmitted through another fiber bundle to the eyepiece or camera, ultimately forming a clear image. Fiberoptic endoscopes offer high-quality imaging and flexible operation, making them suitable for a variety of examinations and treatments. They offer particular advantages in narrow cavities and areas requiring precise manipulation, such as otolaryngology and dentistry.
Classification by Scope Hardness
Rigid endoscopes: Rigid endoscopes are typically constructed of rigid materials, offering a sturdy, non-bending structure. Their advantage lies in providing a stable operating platform, facilitating complex procedures such as biopsy and electrocoagulation.
Rigid endoscopes typically feature a large working channel that can accommodate a variety of therapeutic instruments and are suitable for procedures requiring precise manipulation. However, their rigid structure can limit access to human cavities, causing some discomfort to the patient, and requires greater caution when navigating curved or narrow areas. Rigid endoscopes are commonly used in urology, including cystoscopy and arthroscopic procedures.
Flexible endoscopes: Flexible endoscopes are constructed of soft, flexible materials, such as specialized polymers and fiber optic bundles. This design allows flexible endoscopes to better conform to the natural curvature of the human body, minimizing damage and discomfort to patients. Flexible endoscopes, with precise control of the bending direction and angle of the front end using a handle, enable in-depth observation and manipulation of complex areas of the human body. They are widely used in gastroenterology, including gastroscopy and colonoscopy, and respiratory medicine, including bronchoscopy, providing physicians with more flexible and convenient diagnostic and treatment options. Furthermore, as flexible endoscopes continue to evolve, their capabilities are becoming increasingly powerful. For example, therapeutic flexible endoscopes can simultaneously perform a variety of interventional procedures.
Semi-flexible endoscopes combine the features of both rigid and flexible endoscopes. Their front section is flexible, while the rear section is relatively rigid, providing both operational stability and flexibility. Semi-flexible endoscopes are suitable for specific examination and treatment scenarios. While maintaining operational flexibility, they offer greater support than flexible endoscopes, facilitating more complex procedures. For example, semi-flexible endoscopes offer unique advantages in certain diagnostic and treatment procedures that require deep access to specific areas and demand precise manipulation.
This multi-dimensional classification helps medical professionals gain a deeper understanding of the characteristics and applicable scopes of different types of medical endoscopes. This allows them to precisely select the most appropriate endoscopic device based on the patient's specific condition and treatment needs, improving diagnostic accuracy and treatment effectiveness.
In modern medicine, medical endoscope systems are crucial diagnostic and treatment tools. They come in a wide variety of types and functions, including but not limited to laparoscopes, arthroscopes, otoscopes, nasopharyngoscopes, hysteroscopes, cystoscopes (rigid endoscopes), gastroscopes, and colonoscopes (flexible endoscopes). These devices play an indispensable role in their respective clinical applications:
Laparoscopes are of great value in the diagnosis and treatment of abdominal organ diseases in general surgery and gynecology.
Arthroscopy, used in orthopedics, provides solid support for the accurate diagnosis and minimally invasive treatment of joint diseases. Otoscopes specialize in the examination and treatment of ear diseases.
Nasopharyngoscopes are widely used in otolaryngology for the diagnosis and treatment of nasal and throat diseases.
Hysteroscopes offer unique advantages in the diagnosis and treatment of intrauterine diseases in obstetrics and gynecology.
Cystoscopes (rigid endoscopes) are commonly used in urology for the diagnosis and surgical procedures of bladder and urethral diseases.
Flexible endoscopes such as gastroscopes and colonoscopes, with their superior flexibility and maneuverability, can penetrate deep into the complex regions of the digestive tract, enabling intuitive observation, biopsy, and minimally invasive treatment of a variety of diseases, including inflammation, ulcers, and tumors in the esophagus, stomach, small intestine, and large intestine.
The widespread use of these endoscopic devices in clinical practice has significantly improved the accuracy of disease diagnosis and treatment outcomes, providing a stronger guarantee for patient health. In terms of departmental distribution, soft endoscopes are primarily used in gastroenterology and respiratory medicine. Rigid endoscopes are used more widely, particularly in general surgery, urology, thoracic surgery, and gynecology. According to 2020 data, the proportion of rigid endoscopes used in general surgery was approximately 47.8%, in urology approximately 16.8%, in thoracic surgery approximately 13.2%, in gynecology approximately 12.5%, and in orthopedics approximately 2.6%.
Application Scenarios of Medical Endoscopes
In terms of imaging technology, endoscope systems can be primarily categorized into electronic endoscopes and optical endoscopes. The core difference between the two lies in the fundamental nature of the imaging technology used. Optical endoscope systems primarily rely on optical lenses and a specially designed optical path system to form images through the principle of light reflection. The images generated by these endoscopes exhibit a typical honeycomb lattice structure, with a resolution typically around 20,000 pixels.
In contrast, electronic endoscope systems utilize digital signal processing technology for imaging. Their imaging sensors are primarily classified into charge-coupled devices (CCDs) and complementary metal oxide semiconductors (CMOS). Currently, the resolution of electronic endoscopes has generally reached high-definition standards, and some have even launched ultra-high-definition 4K resolution electronic endoscope systems. This significant improvement in image quality has enabled electronic endoscopes to surpass traditional optical endoscopes in terms of imaging performance. Consequently, electronic endoscopes are gradually replacing optical endoscopes and becoming the dominant product in the market.
Comparison of Electronic and Optical Endoscope Parameters
Based on the bending properties of the scope, medical endoscopes can be divided into two categories: flexible endoscopes and rigid endoscopes. Further subdivided into several types: optical rigid endoscopes, optical semi-rigid endoscopes, optical flexible endoscopes, electronic rigid endoscopes, and electronic flexible endoscopes.
Optical rigid endoscopes primarily consist of a stainless steel alloy housing, a cylindrical optical lens assembly, and a fiber optic system. The internal structure utilizes a cylindrical optical lens assembly for image acquisition and transmission, while the external endoscope tube utilizes a stainless steel alloy tube to ensure the stability of the scope.
Optical rigid endoscopes capture images through an optical objective lens, transmit the image through a lens assembly to the eyepiece for magnification, and ultimately transmit the image to the operator through an eyecup. Optical rigid endoscopes are primarily used in dentistry, otolaryngology, neurology, gastroenterology, surgery, urology, gynecology, and orthopedics.
The optical system of a flexible endoscope consists of an objective lens assembly, an image bundle, and an eyepiece. Its internal structure utilizes a flexible fiber image bundle, while the external tube is made of flexible medical materials to facilitate bending and steering within the body.
Optical flexible endoscopes are primarily used in ophthalmology, respiratory medicine, gastroenterology, surgery, urology, gynecology, and breast surgery. These departments utilize the flexibility and clear imaging capabilities of optical flexible endoscopes for diagnosis and treatment.
Technical Core Barriers of Medical Endoscopy
We will use optical rigid endoscopes and electronic flexible endoscopes as examples to explain their specific characteristics and differences.
Optical Rigid Endoscopes
Optical Rigid Endoscope System Structure and Imaging Principle: An optical rigid endoscope system integrates three core components: a mechanical system, an optical system, and a light-guiding system, which work together to achieve high-definition imaging. Mechanical System Composition
The mechanical system primarily consists of the following components: a stainless steel alloy outer tube, inner tube, lens body, light cone, eyepiece cavity, and a black eyecup made of a high-temperature-resistant polymer material. Within the internal structure, the lens body, outer tube, inner tube, light cone, and eyepiece cavity are all made of stainless steel alloy, ensuring system stability and durability.
In the external structure, the joints between the outer tube and the lens bodies are seamlessly connected by laser welding, effectively isolating the imaging from the external environment and light, enhancing the sealing performance of the objective lens. Furthermore, the lens body and eyecup are secured using precision sealing technology, while the lens body and objective lens are sealed using adhesive or welding to prevent the risk of detachment during operation and prevent liquid leakage and gas intrusion.
Optical System Design
The optical system, consisting of the objective lens, cylindrical lens assembly, and eyepiece assembly, is the core component of imaging. The objective lens is responsible for capturing the image within the cavity, and its lens parameters determine the viewing angle and field of view of the endoscope. The cylindrical lens assembly transmits the image, while the eyepiece assembly magnifies the image and transmits it to the operator through the eyecup.
How the Light Guide System Works
The light guide system consists of an optical fiber approximately 0.03mm in diameter, responsible for transmitting light. Light is emitted from the objective lens, illuminating the cavity. The image is then transmitted through the objective lens body to the other end of the optical fiber system, where it is formed at the light cone. This system ensures sufficient and uniform illumination during diagnosis and treatment, while also maintaining image clarity and contrast.
During image transmission, a micro-image sensor mounted on the tip of an electronic endoscope captures image information and converts optical signals into electrical signals. These signals are then transmitted through the endoscope's internal transmission circuitry to the camera system, where they are ultimately converted and output as high-definition images.
Compared to rigid endoscopes, electronic endoscopes have deeper detection capabilities. Their compact design allows them to easily access narrow cavities, such as the nasal cavity and ear canal, areas that are difficult for rigid endoscopes to reach. Therefore, electronic endoscopes provide clinicians with more precise information about a patient's condition, helping to improve diagnostic accuracy and efficiency.
The imaging principles of electronic endoscopes differ significantly from those of optical endoscopes. Electronic endoscopes use a CCD/CMOS image sensor chip at the tip to capture images and transmit digital signals through the endoscope body. In contrast, fiber-optic endoscopes rely on optical fiber bundles to transmit optical images, without the use of chip circuitry.
In the field of endoscopic diagnosis and treatment, electronic endoscopes play a vital role in hospital endoscopy rooms. It offers several significant advantages, including superior flexibility, high image resolution, ease of clinical diagnosis, and a narrow tube design. These features collectively enhance the efficiency and accuracy of endoscopic examinations.
From front to back, medical endoscopes include the following components: light source, endoscope body, guidewires, main unit, and display. The following details the main functions and features of each component.
Light Source and Illumination
Traditional electronic endoscopes typically use a xenon lamp (white light) as the illumination source. The broadband spectrum of white light is composed of three wavelengths: R/G/B (red/green/blue), with wavelengths of 605nm, 540nm, and 415nm, respectively. In recent years, LED light sources have become widely used in medical endoscopes.
LED light sources are cold light sources with the advantage of not generating heat and are ready for immediate use, providing a more convenient and efficient illumination method for endoscopic examinations.
Lesion Tissue Detection
Traditional methods for lesion tissue detection primarily rely on white light illumination, often combined with chromoendoscopy. The specific procedure involves spraying different pigment solutions onto the mucosa or administering them orally. The differences in the mucosal surface contour or absorption properties are used to distinguish between cancerous and non-cancerous mucosa.
With the advancement of technology, the current method of superimposing fluorescent agents (fluorescence endoscopy) is often used. Specifically, indocyanine green (ICG) is injected into the target blood vessels or tissues. It absorbs near-infrared light and emits fluorescence of varying wavelengths. An image sensor then precisely captures the fluorescence signal, enabling more accurate detection and diagnosis of lesions.
Scope
1. Image Sensor: The color CCD/CMOS image sensor in the scope plays a key role, converting different optical signals into digital electrical signals. By rapidly switching between multiple captured images, dynamic video is ultimately produced, providing the physician with clear, smooth observation.
2. Lens: The lens system is a crucial component of the scope. The standard optical lens offers 10x magnification and a field of view greater than 10mm. On this basis, a zoom lens magnifying endoscope (ME) can be added. By adding a high-magnification zoom lens, mucosal tissue can be optically magnified. Currently, the zoom magnification used by various manufacturers mostly ranges from 80x to 120x, which greatly enhances the ability to observe subtle lesions.
3. Scope Stackability: The scope design offers high flexibility and expandability, allowing for the addition of ultrasound probes to observe tissue structures beneath the surface, providing richer information for disease diagnosis. Furthermore, a confocal microscope (confocal endoscope lens, cytology endoscope) can be added. The confocal probe can be used to obtain histological images at various levels. The application of this technology is expected to significantly reduce the number of biopsies performed, while also improving the positive rate of pathological examinations, providing more accurate and reliable evidence for clinical diagnosis.
Wires
Wires play a crucial role in signal transmission in medical endoscope systems. Encoding circuits accurately transmit signals collected by the image sensor to the image processor via the wires, ensuring stable and accurate signal transmission and providing reliable support for subsequent image processing and analysis.
Host Unit
1. Image Processing: The host unit boasts powerful image processing capabilities, encompassing a variety of advanced processing technologies. These include dual-fluorescence processing and full-color fluorescence processing, enabling precise analysis and processing of fluorescence signals; 4K processing technology, providing high-resolution image display; 3D technology, providing physicians with a three-dimensional viewing perspective; a defog function, effectively resolving endoscope lens fogging issues; a vascular enhancement function, highlighting vascular structures; and specialized image processing features such as high dynamic range processing and exposure correction, further optimizing image quality and providing physicians with clearer, more accurate images.
2. AI Algorithm Processing: The host unit incorporates advanced AI algorithm processing technologies, including AI ISP image processing. This AI algorithm enables in-depth image analysis and processing, enhancing image clarity, contrast, and detail, helping physicians more accurately identify lesion features and improving diagnostic accuracy and efficiency.
Display
As the terminal display device of the medical endoscope system, the display can be configured with either 4K or HD resolution. High-resolution displays can clearly display the image information captured by the endoscope, providing doctors with a more detailed and realistic view, helping them more accurately diagnose the condition and develop appropriate treatment plans.
Among the key components of an endoscope, technical barriers primarily exist in the following core areas:
Imaging System Lens
The image resolution of an endoscope is a key factor in determining image clarity and is directly related to the detection rate and accuracy of clinical disease screening. As the core component for capturing light signals, the optical lens has extremely high technical requirements. Japanese companies have a deep technical foundation in the camera and optics sectors, particularly in zoom lens design and multi-stop optical magnification technology, and hold a rich patent portfolio. In contrast, Chinese manufacturers still lag significantly behind in the accumulation of high-end CNC machine tool processing and technology patents.
Image Sensor
Image sensors convert optical information into electrical signals. Currently, the market primarily consists of two types of sensors: CCD and CMOS. CCD technology has long been monopolized by Japanese companies. In 2019, the top seven global CCD manufacturers were all Japanese, accounting for 98.5% of the market share. Compared to CCDs, CMOS sensors offer advantages such as small size, low power consumption, low cost, and high system integration. They are expected to gradually replace CCDs in endoscopes.
Medical endoscopes are undergoing an accelerated evolution from auxiliary tools to multifunctional platforms. From basic observation and diagnosis to complex minimally invasive treatments, breakthroughs in core technologies and integrated innovation will determine companies' core competitiveness in the future market. With the continued expansion of global demand for minimally invasive medical care and the integration of artificial intelligence, high-definition imaging, and remote collaboration technologies, the endoscopy industry is poised for another round of innovation and rapid growth.
