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Wednesday, January 30, 2013

Surgeons may use hand gestures to manipulate MRI images in OR

Jan. 10, 2013 — Doctors may soon be using a system in the operating room that recognizes hand gestures as commands to tell a computer to browse and display medical images of the patient during a surgery.

Surgeons routinely need to review medical images and records during surgery, but stepping away from the operating table and touching a keyboard and mouse can delay the procedure and increase the risk of spreading infection-causing bacteria, said Juan Pablo Wachs, an assistant professor of industrial engineering at Purdue University.

"One of the most ubiquitous pieces of equipment in U.S. surgical units is the computer workstation, which allows access to medical images before and during surgery," he said. "However, computers and their peripherals are difficult to sterilize, and keyboards and mice have been found to be a source of contamination. Also, when nurses or assistants operate the keyboard for the surgeon, the process of conveying information accurately has proven cumbersome and inefficient since spoken dialogue can be time-consuming and leads to frustration and delays in the surgery."

Researchers are creating a system that uses depth-sensing cameras and specialized algorithms to recognize hand gestures as commands to manipulate MRI images on a large display. Recent research to develop the algorithms has been led by doctoral student Mithun George Jacob.

Findings from the research were detailed in a paper published in December in the Journal of the American Medical Informatics Association. The paper was written by Jacob, Wachs and Rebecca A. Packer, an associate professor of neurology and neurosurgery in Purdue's College of Veterinary Medicine.

The researchers validated the system, working with veterinary surgeons to collect a set of gestures natural for clinicians and surgeons. The surgeons were asked to specify functions they perform with MRI images in typical surgeries and to suggest gestures for commands. Ten gestures were chosen: rotate clockwise and counterclockwise; browse left and right; up and down; increase and decrease brightness; and zoom in and out.

Critical to the system's accuracy is the use of "contextual information" in the operating room -- cameras observe the surgeon's torso and head -- to determine and continuously monitor what the surgeon wants to do.

"A major challenge is to endow computers with the ability to understand the context in which gestures are made and to discriminate between intended gestures versus unintended gestures," Wachs said. "Surgeons will make many gestures during the course of a surgery to communicate with other doctors and nurses. The main challenge is to create algorithms capable of understanding the difference between these gestures and those specifically intended as commands to browse the image-viewing system. We can determine context by looking at the position of the torso and the orientation of the surgeon's gaze. Based on the direction of the gaze and the torso position we can assess whether the surgeon wants to access medical images."

The hand-gesture recognition system uses a camera developed by Microsoft, called Kinect, which senses three-dimensional space. The camera, found in consumer electronics games that can track a person's hands, maps the surgeon's body in 3-D. Findings showed that integrating context allows the algorithms to accurately distinguish image-browsing commands from unrelated gestures, reducing false positives from 20.8 percent to 2.3 percent.

"If you are getting false alarms 20 percent of the time, that's a big drawback," Wachs said. "So we've been able to greatly improve accuracy in distinguishing commands from other gestures."

The system also has been shown to have a mean accuracy of about 93 percent in translating gestures into specific commands, such as rotating and browsing images.

The algorithm takes into account what phase the surgery is in, which aids in determining the proper context for interpreting the gestures and reducing the browsing time.

"By observing the progress of the surgery we can tell what is the most likely image the surgeon will want to see next," Wachs said.

The researchers also are exploring context using a mock brain biopsy needle that can be tracked in the brain.

"The needle's location provides context, allowing the system to anticipate which images the surgeon will need to see next and reducing the number of gestures needed," Wachs said. "So instead of taking five minutes to browse, the surgeon gets there faster."

Sensors in the surgical needle reveal the position of its tip.

The research was supported by the Agency for Healthcare Research and Quality, grant number R03HS019837.

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The above story is reprinted from materials provided by Purdue University. The original article was written by Emil Venere.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

M. G. Jacob, J. P. Wachs, R. A. Packer. Hand-gesture-based sterile interface for the operating room using contextual cues for the navigation of radiological images. Journal of the American Medical Informatics Association, 2012; DOI: 10.1136/amiajnl-2012-001212

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Monday, June 18, 2012

Scientists develop biological computer to encrypt and decipher images

ScienceDaily (Feb. 7, 2012) — Scientists at The Scripps Research Institute in California and the Technion-Israel Institute of Technology have developed a "biological computer" made entirely from biomolecules that is capable of deciphering images encrypted on DNA chips. Although DNA has been used for encryption in the past, this is the first experimental demonstration of a molecular cryptosystem of images based on DNA computing.

The study was published in a recent online-before-print edition of the journal Angewandte Chemie.

Instead of using traditional computer hardware, a group led by Professor Ehud Keinan of Scripps Research and the Technion created a computing system using bio-molecules. When suitable software was applied to the biological computer, it could decrypt, separately, fluorescent images of The Scripps Research Institute and Technion logos.

A Union Between Biology and Computer Science

In explaining the work's union of the often-disparate fields of biology and computer science, Keinan notes that a computer is, by definition, a machine made of four components -- hardware, software, input, and output. Traditional computers have always been electronic, machines in which both input and output are electronic signals. The hardware is a complex composition of metallic and plastic components, wires, and transistors, and the software is a sequence of instructions given to the machine in the form of electronic signals.

"In contrast to electronic computers, there are computing machines in which all four components are nothing but molecules," Keinan said. "For example, all biological systems and even entire living organisms are such computers. Every one of us is a biomolecular computer, a machine in which all four components are molecules that 'talk' to one another logically."

The hardware and software in these devices, Keinan notes, are complex biological molecules that activate one another to carry out some predetermined chemical work. The input is a molecule that undergoes specific, predetermined changes, following a specific set of rules (software), and the output of this chemical computation process is another well-defined molecule.

"Building" a Biological Computer

When asked what a biological computer looks like, Keinan laughs.

"Well," he said, "it's not exactly photogenic." This computer is "built" by combining chemical components into a solution in a tube. Various small DNA molecules are mixed in solution with selected DNA enzymes and ATP. The latter is used as the energy source of the device.

"It's a clear solution -- you don't really see anything," Keinan said. "The molecules start interacting upon one another, and we step back and watch what happens." And by tinkering with the type of DNA and enzymes in the mix, scientists can fine-tune the process to a desired result.

"Our biological computing device is based on the 75-year-old design by the English mathematician, cryptanalyst, and computer scientist Alan Turing," Keinan said. "He was highly influential in the development of computer science, providing a formalization of the concepts of algorithm and computation, and he played a significant role in the creation of the modern computer. Turing showed convincingly that using this model you can do all the calculations in the world. The input of the Turing machine is a long tape containing a series of symbols and letters, which is reminiscent of a DNA string. A reading head runs from one letter to another, and on each station it does four actions: 1) reading the letter; 2) replacing that letter with another letter; 3) changing its internal state; and 4) moving to next position. A table of instructions, known as the transitional rules, or software, dictates these actions. Our device is based on the model of a finite state automaton, which is a simplified version of the Turing machine. "

Unique Biological Properties

Now that he has shown the viability of a biological computer, does Keinan hope that this model will compete with its electronic counterpart?

"The ever-increasing interest in biomolecular computing devices has not arisen from the hope that such machines could ever compete with electronic computers, which offer greater speed, fidelity, and power in traditional computing tasks," Keinan said. "The main advantages of biomolecular computing devices over electronic computers have to do with other properties."

As shown in this work, he continues, a wealth of information can be stored and encrypted in DNA molecules. Although each computing step is slower than the flow of electrons in an electronic computer, the fact that trillions of such chemical steps are done in parallel makes the entire computing process fast. "Considering the fact that current microarray technology allows for printing millions of pixels on a single chip, the numbers of possible images that can be encrypted on such chips is astronomically large," he said.

"Also, as shown in our previous work and other projects carried out in our lab, these devices can interact directly with biological systems and even with living organisms," Keinan explained. "No interface is required since all components of molecular computers, including hardware, software, input, and output, are molecules that interact in solution along a cascade of programmable chemical events." He adds that because of DNA's ability to store information, major computer companies have been extremely interested in the development of DNA-based computing systems.

The first author of the study, "A Molecular Cryptosystem for Images by DNA Computing," is graduate student Sivan Shoshani of Technion. In addition to Keinan and Shoshani, authors include postdoctoral fellow Ron Piran of Scripps Research and Yoav Arava of the Technion.

This work was supported by the National Science Foundation, the Israel-US Binational Science Foundation, and the Skaggs Institute for Chemical Biology, as well as graduate fellowships from the Irwin and Joan Jacobs Foundation, the Fine Foundation, the Russell Berrie Nanotechnology Institute, and the Israel Ministry of Science and Technology.