Phone camera becomes mini-microscope for diagnostics
HELSINKI, and SOLNA, Sweden – Microscopy is relatively easy to perform and at low cost, which makes it a universal diagnostic method for most globally important parasitic infections. But many methods are limited to well-equipped laboratories and are difficult to maintain at the basic levels of health care due to lack of resources and adequately trained personnel.
Researchers at the Institute for Molecular Medicine Finland (FIMM) at the University of Helsinki and at the Karolinska Institute in Sweden recently showed that new techniques for high-resolution imaging and image transfer over data networks may be utilized to solve these diagnostic problems.
A test sample is placed directly on the exposed surface of the image sensor chip after removal of the optics. The resolution of such mini-microscopes is dependent on the pixel size of the sensor, but sufficient for identification of several pathogenic parasites. Photo by Heli Vilmi; courtesy of Johan Lundin Lab.
A team led by Dr. Johan Lundin of FIMM and Dr. Ewert Linder of the Karolinska Institute modified inexpensive imaging devices – €10 webcams and mobile phone cameras – to turn them into mini-microscopes. They placed test samples directly on the exposed surface of the image sensor chip after removal of the optics. The resolution of the devices depended on the sensor’s pixel size but was sufficient to identify several pathogenic parasites.
In their study, published in PLOS Neglected Tropical Diseases (doi: 10.1371/journal.pntd.0002547), the researchers used the mini-microscopes they constructed to yield images of parasitic worm eggs present in urine and stools of infected individuals. They first used this novel approach to detect urinary schistosomiasis, a severely underdiagnosed infection affecting hundreds of millions, primarily in sub-Saharan Africa. For point-of-care diagnostics, they developed a highly specific pattern-recognition algorithm to analyze the image from the mini-microscope and automatically detect parasite eggs.
“The results can be exploited for constructing simple imaging devices for low-cost diagnostics of urogenital schistosomiasis and other neglected tropical infectious diseases,” Lundin said. “With the proliferation of mobile phones, data transfer networks and digital microscopy applications, the stage is set for alternatives to conventional microscopy in endemic areas.”
- A precisely defined series of steps that describes how a computer performs a task.
- A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture and a shutter of variable speed to precisely control the exposure. In an electronic imaging system, the camera does not use chemical means to store the image, but takes advantage of the sensitivity of various detectors to different bands of the electromagnetic spectrum. These sensors are transducers...
- An instrument consisting essentially of a tube 160 mm long, with an objective lens at the distant end and an eyepiece at the near end. The objective forms a real aerial image of the object in the focal plane of the eyepiece where it is observed by the eye. The overall magnifying power is equal to the linear magnification of the objective multiplied by the magnifying power of the eyepiece. The eyepiece can be replaced by a film to photograph the primary image, or a positive or negative relay...
- Contraction of "picture element." A small element of a scene, often the smallest resolvable area, in which an average brightness value is determined and used to represent that portion of the scene. Pixels are arranged in a rectangular array to form a complete image.
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