Technological enhancements in the medical sector are reaching new heights, from performing remote diagnoses to executing computer-aided and robot-guided surgeries, new feats that have seemed like science fiction in the past are being realized today. For example, it is possible to obtain a close view of human anatomy, including our cells, using powerful microscopes and tiny robots inserted inside the human body.
Obtaining high-resolution images of body organs and parts is also more accessible, thanks to massive advancements in medical science. However, would you want a 3-dimensional view of blood vessels, tiny nerves, and cancerous cells? This is possible.
A team of researchers with the University of Texas Southwestern Medical Center worked with fellow researchers in Australia and England to create and test a unique and advanced optical device. It turns microscopes into projection imaging systems with multiple angles. The invention has been published in Nature Methods.
3D imaging
The project was led by Kevin Dean, Ph.D., and Reto Fiolka, Ph.D. They are cell biology professors in the Bioinformatics Department at the University of Texas Southwestern (UTSW). Dean, who also serves as the UTSW Microscopy Innovation Laboratory director, said: “It is as if you are holding the biological specimen with your hand, rotating it, and inspecting it, which is an incredibly intuitive way to interact with a sample. By rapidly imaging the sample from two different perspectives, we can interactively visualize the sample in virtual reality on the fly.”
Obtaining 3D image information from any microscope is a data-intensive process. First, it requires hundreds of 2D images to be turned into an image stack. Next, the image stack is manipulated through a graphics software program to visualize the collected data. The software then executes lengthy computations to create two-dimensional projections from multiple viewing perspectives on a PC display. These need the usage of a potent and costly PC, and the steps require a considerable amount of time.
The UT Southwestern team figured it was possible to form projections from varying angles through optical means. As a result, they did not have to deploy image stacks and then render these using a PC. Instead, they used two rotating mirrors inserted at the front side of the microscope camera. Fiolka said: “As a result, we can do all this in real-time, without noticeable delay.”
A ‘live’ look
“Surprisingly, we can look ‘live’ at samples of our cells from different angles without rotating the samples or the microscope. We believe this invention may represent a new paradigm for acquiring 3D information via the fluorescence microscope.”
This new method promises fast imaging, in addition, it can work with single camera exposure. At the beginning of the research, the researchers set up a system with a couple of light-sheet microscopes. This required a post-processing step for data analysis known as de-skewing and involves rearranging the individual images to remove 3D-image stack distortions.
The scientists wanted to execute the de-skewing optically. While trying the optical de-skewing process, they fathomed that the projected image rotates when an improper amount of “de-skew” is used. They also realized that the system might work for different types of microscopes and Dean said they tried the method using various types.
Paving the way for future applications
Fiolka said the technology is new, but the theoretical foundations are old. The invention can pave the way for advancing medical research to new levels. For example, physicians and researchers can use the method to obtain very close views of the veins and cells in the human body in 3D. This will not have to invest in costly computer setups given the developed methodology.
The team also used the microscope to visualize calcium ions carrying nerve signals and even imaged a beating zebrafish heart and inspected cancer cells.
