Experimental Evaluation and Analysis of LED Illumination Source for Endoscopy Imaging (original) (raw)
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Development and evaluation of a light-emitting diode endoscopic light source
Advanced Biomedical and Clinical Diagnostic Systems X, 2012
Light-emitting diode (LED) based endoscopic illumination devices have been shown to have several benefits over arclamp systems. LEDs are energy-efficient, small, durable, and inexpensive, however their use in endoscopy has been limited by the difficulty in efficiently coupling enough light into the endoscopic light cable. We have demonstrated a highly homogenised lightpipe LED light source that combines the light from four Luminus LEDs emitting in the red, green, blue and violet using innovative dichroics that maximise light throughput. The light source spectrally combines light from highly divergent incoherent sources that have a Lambertian intensity profile to provide illumination matched to the acceptance numerical aperture of a liquid light guide or fibre bundle. The LED light source was coupled to a standard laparoscope and performance parameters (power, luminance, colour temperature) compared to a xenon lamp. Although the total illuminance from the endoscope was lower, adjustment of the LEDs' relative intensities enabled contrast enhancement in biological tissue imaging. The LED light engine was also evaluated in a minimally invasive surgery (MIS) box trainer and in vivo during a porcine MIS procedure where it was used to generate 'narrowband' images. Future work using the violet LED could enable photodynamic diagnosis of bladder cancer.
Multi-channel LED light source for fluorescent agent aided minimally invasive surgery
2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014
Cancer is one of the most common and deadly diseases around the world. Amongst all the different treatments of cancer such as surgery, chemotherapy and radiation therapy, surgical resection is the most effective. Successful surgeries greatly rely on the detection of the accurate tumor size and location, which can be enhanced by contrast agents. Commercial endoscope light sources, however, offer only white light illumination. In this paper, we present the development of a LED endoscope light source that provides 2 light channels plus white light to help surgeons to detect a clear tumor margin during minimally invasive surgeries. By exciting indocyanine green (ICG) and 5-Aminolaevulinic acid (ALA)-induced protoporphyrin IX (PPIX), the light source is intended to give the user a visible image of the tumor margin. This light source is also portable, easy to use and costs less than $300 to build.
Surgical Endoscopy and Other Interventional Techniques, 2009
Introduction Current arc-lamp illumination systems have a number of technical and ergonomic limitations. White light-emitting diodes (LEDs) are energy-efficient solidstate lighting devices which are small, durable and inexpensive. Their use as an alternative to arc-lamp light sources in minimal access surgery has not been explored. This study aims to develop an LED-based endo-illuminator and to determine its lighting characteristics for use in minimal access surgery. Methods We developed an LED endo-illuminator using a white LED mounted at the tip of a steel rod. Offline image analysis was carried out to compare the illuminated field using the LED endo-illuminator or an arc-lamp based endoscope in terms of uniformity, shadow sharpness and overall image intensity. Direct radiometric power measurements in light intensity and stability were obtained. Visual perception of fine details at the peripheral endoscopic field was assessed by 13 subjects using the different illumination systems. Results Illumination from the LED endo-illuminator was more uniform compared to illumination from an arc-lamp source, especially at the closer distance of 4 cm (0.0006 versus 0.0028 arbitrary units -lower value indicates more uniform illumination). The shadows were also sharper (edge widths of 16 versus 44 pixels for the first edge and 15 versus 61 pixels for the second edge). The overall mean image intensity was higher (127 versus 100 arbitrary units) when using the autoshutter mode despite the lower direct radiometric power, about one tenth of the arc-lamp endoscopic system. The illumination was also more stable with less flickering (0.02% versus 5% of total power in non-DC components). Higher median scores on visual perception was also obtained (237 versus 157, p \ 0.001). Conclusion The LED endo-illuminator provides more uniform illumination with sharper shadows, less flickering and better illumination for visual perception than the arclamp-based system currently used.
Choosing Surgical Lighting in the LED Era
Surgical Innovation, 2009
Background. The aim of this study is to evaluate the illumination characteristics of LED lights objectively to ease the selection of surgical lighting. Methods. The illuminance distributions of 5 main and 4 auxiliary lights were measured in 8 clinically relevant scenarios. For each light and scenario, the maximum illuminance E c (klux) and the size of the light field d 10 (mm) were computed. Results. The results showed: that large variations for both E c (25-160 klux) and d 10 (109-300 mm) existed; that using auxiliary lights reduced both E c and d 10 by up to 80% and 30%; that with segmented lights, uneven light distributions occurred; and that with colored LED lights shadow edges on the surgical field became colored. Conclusions. Objective illuminance measurements show a wide variation between lights and a superiority of main over auxiliary lights. Uneven light distributions and colored shadows indicate that LED lights still need to converge to an optimal design.
Feasibility of using an led-probe in third-space endoscopy: a clinical study
BMC Gastroenterology, 2020
Background Third-space endoscopy is a novel, safe, and effective method for treating different gastrointestinal conditions. However, several failed endoscopic procedures are attributed to incomplete myotomy. Lighting devices are used to prevent organic injuries. We aimed to investigate the feasibility of using a hand-made LED-probe (LP) in third-space procedures. Methods This prospective study was conducted in a tertiary-care center in Mexico between December 2016 and January 2019. We included peroral endoscopic myotomy (POEM) and gastric peroral endoscopic myotomy(G-POEM) procedures. Pseudoachalasia, peptic ulcer, normal gastric emptying scintigraphy (GES) and prepyloric tumors were excluded. LP was used to guide or confirm procedures. Clinical and procedural characteristics were recorded and analyzed. Results Seventy third-space procedures were included (42POEM,28G-POEM), with an average patient age of 46.7 ± 14.3 and 43.7 ± 10.1 years, respectively. For the POEM and G-POEM groups...
Characterization of multi-emitter tuneable led source for endoscopic applications
2019
In this paper we describe our own construction of a tuneable light source based on a set of light emitting diodes covering the visible spectrum using a homogenizing rod instead commonly used low energy-efficient integrating spheres. The expected prime application of the source is a medical endoscopic system, however it is possible to use it also for other purposes requiring both multispectral operation and a tuneable white light source. We describe the construction of the source and include precise characterization of the output white light – distribution of CCT, Duv, Δu′ v ′ and colour rendering indexes (Ra, R9, Rf , Rg) of light in several planes located at various distances. The obtained results prove that our source is characterized by very good colour rendition according to the Ra and Rf method for various correlated colour temperatures (2700–6500) K. As an example of application images of the Macbeth colour chart registered with an RGB camera included in the laboratory measure...
Evaluation of a new surgical light source for difficult visibility procedures
Surgical innovation, 2011
A new lighting device for open surgery of difficult access wounds was designed: the Extender add-on. The performance of the Extender is evaluated and compared with the conventional solutions used in the operating room (OR) on illumination quality. A cylindrical setup was built to measure the distribution of light in a simulated pelvic wound. The light was provided by a head-mounted light, an OR light, and a pair of Extender prototypes. The results showed that the Extender prototypes provided 12.2 lumens inside the wound, whereas the head-mounted light gave 5.7 lumens. The Extenders provided smoothly angular distributed light from 0° to 180°, whereas the head-mounted light and OR light only provided light from 115° to 180°. The Extender prototypes had a promising performance in terms of light distribution. It is expected that a more accurately produced Extender will increase performance in terms of illumination quantity and illumination distribution smoothness even further.
Light-Emitting Diode-Assisted Narrow Band Imaging Video Endoscopy System in Head and Neck Cancer
Clinical Endoscopy, 2015
The use of narrow band imaging (NBI) is currently considered of great benefit in detecting superficial mucosal lesions over the pharyngeal mucosa. 3 A literature review revealed that the effectiveness of NBI in the early detection of head and neck squamous cell carcinoma (SCC) of the larynx, 4 mouth floor, 5 nasopharynx, 6 oropharynx, and hypopharynx 7,8 has been documented over time. The NBI system (Olympus Medical Systems, Tokyo, Japan) is a noninvasive optical device that uses reflected light to visualize the superficial structure and enhance vasculature within the mucosal layer. NBI provides a unique image that emphasizes the morphological and structural character of lesions as well as their surface capillary patterns. The first clinical study of the NBI system for the diagnosis of gastrointestinal tumors was reported by Sano et al. 9 in 2001. Unique images are created by the sequential lighting of the tissue through an endoscope, and the sequence of light is produced by a rotation disk with red, green, and blue optical filters placed in front of a high-power white light source, typically a xenon lamp. The physical phenomena are based on the fact that the penetration depth of light is dependent on its wavelength (i.e., Background/Aims: To validate the effectiveness of a newly developed light-emitting diode (LED)-narrow band imaging (NBI) system for detecting early malignant tumors in the oral cavity. Methods: Six men (mean age, 51.5 years) with early oral mucosa lesions were screened using both the conventional white light and LED-NBI systems. Results: Small elevated or ulcerative lesions were found under the white light view, and typical scattered brown spots were identified after shifting to the LED-NBI view for all six patients. Histopathological examination confirmed squamous cell carcinoma. The clinical stage was early malignant lesions (T1), and the patients underwent wide excision for primary cancer. This is the pilot study documenting the utility of a new LED-NBI system as an adjunctive technique to detect early oral cancer using the diagnostic criterion of the presence of typical scattered brown spots in six high-risk patients. Conclusions: Although large-scale screening programs should be established to further verify the accuracy of this technology, its lower power consumption, lower heat emission, and higher luminous efficiency appear promising for future clinical applications.
This article describes the feasibility of using smartphones as an alternative light source in endoscopic procedures by comparing it to conventional light sources. Therefore, we used an adapter designed and printed in 3D, combined with an iPhone 6S, ear endoscope L. 50mm diam. 4mm 0 ° and a cardboard as dark anterior. Tests have shown that the illumination is adequate and sufficient, and the results obtained are satisfactory. As a conclusion, this adapter and method finds its place in clinical emergency situations and when endoscopy tower or portable light source might not be available especially in low-and middle-income countries (LMCIs).
Asian journal of endoscopic surgery, 2014
Organic electroluminescence displays (OELD) use organic materials that self-emit light with the passage of an electric current. OELD provide high contrast, excellent color reproducibility at low brightness, excellent video images, and less restricted viewing angles. OELD are thus promising for medical use. This study compared the utility of an OELD with conventional liquid crystal displays (LCD) for imaging in orthopedic endoscopic surgery. One OELD and two conventional LCD that were indistinguishable in external appearance were used in this study. Images from 18 patients were displayed simultaneously on three monitors and evaluated by six orthopedic surgeons with extensive surgical experience. Images were shown for 2 min, repeated twice, and viewed from the front and side (diagonally). Surgeon rated both clinical utility (12 parameters) and image quality (11 parameters) for each image on a 5-point scale: 1, very good; 2, good; 3, average; 4, poor; and 5, very poor. For clinical uti...