Optical microsystem design and fabrication for medical image magnification

Costa, Carlos A. Bana e; Gomes, J. M.; Wolffenbuttel, R.F.; Correia, J. H.

doi:10.1007/s00542-016-2830-6

Cited by 6 publications

(7 citation statements)

References 4 publications

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“…The numerical aperture (NA) and the depth of focus (δz) are given by Equations (5) and (6), respectively [11]. Table 3 presents the calculated PDMS refractive index (n) by Equation (4), focal point (f) by Equation (3), and δz for each LED wavelength (λ), considering the fabricated µ-lens with a 3.9 mm base diameter and a 0.52 mm central height.…”

Section: Resultsmentioning

confidence: 99%

“…This work presents a µ-lens placed on top of LEDs to increase the light intensity at the target area of interest, without increasing the power consumption of the system. The µ-lenses are used in many optical applications, such as optical communications, optical systems for digital imaging, biomedical optical imaging, and optoelectronics [ 11 , 12 , 13 , 14 , 15 ]. There are several reported methods to produce µ-lenses, including dielectrophoresis force [ 16 ], lithography [ 17 ], ink jet printing [ 18 ], RIE (reactive ion etching) [ 19 ], the Litographie, Galvanoformung, and Abformung (LIGA) process [ 20 ], hot embossing [ 21 ], deep proton irradiation [ 22 ], and nanoimprint techniques [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

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PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics

Costa

Pimenta

Ribeiro

et al. 2019

Sensors

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Minimally invasive medical devices can greatly benefit from Narrow Band Imaging (NBI) diagnostic capabilities, as different wavelengths allow penetration of distinct layers of the gastrointestinal tract mucosa, improving diagnostic accuracy and targeting different pathologies. An important performance parameter is the light intensity at a given power consumption of the medical device. A method to increase the illumination intensity in the NBI diagnostic technique was developed and applied to minimally invasive medical devices (e.g., endoscopic capsules), without increasing the size and power consumption of such instruments. Endoscopic capsules are generally equipped with light-emitting diodes (LEDs) operating in the RGB (red, green, and blue) visible light spectrum. A polydimethylsiloxane (PDMS) µ-lens was designed for a maximum light intensity at the target area of interest when placed on top of the LEDs. The PDMS µ-lens was fabricated using a low-cost hanging droplet method. Experiments reveal an increased illumination intensity by a factor of 1.21 for both the blue and green LEDs and 1.18 for the red LED. These promising results can increase the resolution of NBI in endoscopic capsules, which can contribute to early gastric lesions diagnosis.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics

Costa

Pimenta

Ribeiro

et al. 2019

Sensors

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“…Costa et al proposed an integration of an imaging magnification optical microsystem (IMON), including a PDMS lens, which was able to perform in vivo and real-time tissue microscopy (Figure 6). With total length of 12.164 mm and a lateral lens assembly of 3.894 mm, a paraxial magnification of 4-14 times was achieved with great performance [113]. In this sequence of ideas, another similar IMON for ECs can be found in the work developed by Ribeiro et al [117].…”

Section: Laser Endomicroscopymentioning

confidence: 98%

“…This is mainly due to the possibility of increased risk of perforation of the intestine, taking into account its reduced thickness and sinuous structure [12]. On the basis of the above reasons, the endoscopic capsule (EC) becomes a means of excellence to implement a form of photodynamic therapy (PDT) using light emitting diodes (LEDs) with wavelength in the region of red (e.g., from 620nm to750nm) that can be incorporated into EC, as shown in Figure 5(a) [113], allowing this equipment the ability to perform treatment in the GI system. Naturally, it is necessary to carry out preliminary tests on biopsies of the patient's own cells in order to define the doses of both the photosensitizers and light, as well as, the exposure time in the endoscopic capsule to be applied during the treatment itself.…”

Section: Photodybamic Therapymentioning

confidence: 99%

Endoscope Capsules: Present Situation and Future Outlook

Gounella¹,

Ando²,

Carmo³

2023

Preprint

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This paper presents new perspectives of photonic technologies for capsule endoscopy. It is firstly presented a review about conventional endoscopy (upper endoscopy and colonoscopy), followed by capsule endoscopy (CE), as well as their techniques, advantages, and drawbacks. The technologies for CEs presented in this paper have the potential of integration on the existing endoscopic systems commercially available. Such technologies include narrow band imaging (NBI), photodynamic therapy (PDT), confocal laser endomicroscopy (CLE), Optical coherence tomography (OCT) and Spectroscopy in order to improve the performance of the GI tract examination. In the context of NBI, two optical filters were designed and fabricated for integration into endoscopic capsules, allowing the visualization of light centered at the 415 nm and 540 nm. These optical filters are based on the principle of Fabry-Perot and were made of thin-films of titanium dioxide (TiO2) and silicon dioxide (SiO2). Moreover, strategies and aid solutions for the adaptation of ECs for PDT are also discussed.

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“…[7][8][9] Further, these miniature lenses can be used in developing imaging systems for optical microsystem platforms, e.g., endoscopes. 10 Various types of miniature lenses, e.g., ball lens, 11,12 parabolic lens, 9,13 plano-convex spherical lens, 8 and reversed mobile phone camera lens, 14 have been attached to smartphone cameras without hardware modifications. Thermal reflow, 15 inkjet printing, 16 photolithography, 17 glass etching, 18 and water-based molds 19 are some of the established lens fabrication techniques.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control

et al. 2018

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Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with ∼1.4-μm resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance.

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Optical microsystem design and fabrication for medical image magnification

Cited by 6 publications

References 4 publications

PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics

PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics

Endoscope Capsules: Present Situation and Future Outlook

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control

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